rock unit,unit name,age,description,fossil,radiometric age,source,class,quadrangle,rock class,nsaclass,label,nsamod,qclass
Q,Undifferentiated surficial deposits,Quaternary,"The deposits include alluvium, colluvium, talus, landslides, rock glaciers, eolian and paludal deposits, and a variety of lacustrine, morainal, and ice contact.",,,VA002,100,Valdez,Unconsolidated,100,,,1000
Qs,Surficial deposits,Holocene and Pleistocene,"Surficial deposits, undifferentiated",,,GU002,100,Gulkana,Unconsolidated,100,,,1000
Qs,"Surficial deposits, undifferentiated",Holocene,"Surficial deposits, undifferentiated -- Alluvium deposited by nonglacial streams and outwash deposited by glacial meltwater.",,,CV003,110,Cordova,Unconsolidated,100,,,1000
Qu,"Surficial deposits, undivided",Holocene,"Predominantly alluvium deposited by nonglacial streams and outwash deposited by glacial meltwater. Consists of sand and gravel; terminal, lateral, and ground moraine composed of unsorted deposits of boulders, cobbles, gravel, and sand left by the retreat of alpine, valley, and regional glaciers; and talus and landslide deposits from adjacent bedrock. Also includes less extensive deposits consisting mostly of sand that may be locally abundant and form such features as beaches, spits, offshore bars in coastal areas, and dunes on the Copper River delta. Surficial deposits, undivided",,,CV002,100,Cordova,Unconsolidated,100,,,1000
Qu,"Surficial deposits, undivided",Holocene,"Predominantly alluvium deposited by nonglacial streams and outwash deposited by glacial meltwater. Consists of sand and gravel; terminal, lateral, and ground moraine composed of unsorted deposits of boulders, cobbles, gravel, and sand left by the retreat of alpine, valley, and regional glaciers; and talus and landslide deposits from adjacent bedrock. Also includes less extensive deposits consisting mostly of sand that may be locally abundant and form such features as beaches, spits, offshore bars in coastal areas, and dunes on the Copper River delta. Surficial deposits, undivided",,,BG003,100,Bering Glacier,Unconsolidated,100,,,1000
Qu,"Surficial deposits, undivided",Holocene,"Predominantly alluvium deposited by nonglacial streams and outwash deposited by glacial meltwater. Consists of sand and gravel; terminal, lateral, and ground moraine composed of unsorted deposits of boulders, cobbles, gravel, and sand left by the retreat of alpine, valley, and regional glaciers; and talus and landslide deposits from adjacent bedrock. Also includes less extensive deposits consisting mostly of sand that may be locally abundant and form such features as beaches, spits, offshore bars in coastal areas, and dunes on the Copper River delta. Surficial deposits, undivided",,,CV002,100,Cordova,Unconsolidated,100,,,1000
Qu,"Surficial deposits, undivided",Holocene,"Predominantly alluvium deposited by nonglacial streams and outwash deposited by glacial meltwater. Consists of sand and gravel; terminal, lateral, and ground moraine composed of unsorted deposits of boulders, cobbles, gravel, and sand left by the retreat of alpine, valley, and regional glaciers; and talus and landslide deposits from adjacent bedrock. Also includes less extensive deposits consisting mostly of sand that may be locally abundant and form such features as beaches, spits, offshore bars in coastal areas, and dunes on the Copper River delta. Surficial deposits, undivided",,,VA003,6100,Valdez,Unconsolidated,100,,,1000
Qu,Undifferentiated surficial deposits,Quaternary,"Undifferentiated slope deposits, including glacial and alluvial deposits.",,,MC004,410,McCarthy,Unconsolidated,107,,,1070
Qu,Undifferentiated surficial deposits,Quaternary,"Alluvium, older alluvium, colluvium, talus, landslides, rock glaciers, glaciolacustrine deposits, glacial outwash deposits, and a variety of moraines",,,MC002,25,McCarthy,Unconsolidated,100,,,1000
yellow,Recent glacio-fluvial deposits,"Quaternary, Holocene",glacio-fluvial deposits,,,CV005,502,Cordova,Unconsolidated,100,,,1000
yellow,Recent glacio-fluvial deposits,"Quaternary, Holocene",Glacio-fluvial deposits,,,CV006,502,Cordova,Unconsolidated,100,,,1000
Qa,Alluvial deposits,Holocene,"Alluvium of active flood plains and lowest terraces of major streams, and larger alluvial fans. Boulders, gravel, and sand",,,NB002,100,Nabesna,Unconsolidated,105,,,1050
Qau,Alluvial deposits,Holocene and Pleistocene,"Alluvium, undivided",,,NB002,101,Nabesna,Unconsolidated,109,,,1090
Qa,Alluvial deposits,Holocene,Alluvial deposits,,,GU002,106,Gulkana,Unconsolidated,105,,,1050
Qs,Alluvium,Holocene,Primarily well-sorted stratified gravel and sand deposited by nonglacial streams and outwash deposited by glacial meltwater. Locally includes lake and terrace deposits,,,BG002,113,Bering Glacier,Unconsolidated,105,,,1050
Qal,Alluvium along streams and in fans,Holocene,"Mainly in active flood plains and lowermost terraces of major and some minor streams and in larger active fans. Stratified silt, sand, gravel, and boulders.",,,MC003,200,McCarthy,Unconsolidated,105,,,1050
Qa,Active alluvium,Quaternary,Active alluvium in larger streams and fans,,,MC004,400,McCarthy,Unconsolidated,105,,,1050
Qal,Alluvium along streams,Holocene,"Mainly in active flood plains of major and some minor streams. Chiefly stratified boulders, cobbles, gravel, and sand; silt locally common.",,,NB008,801,Nabesna,Unconsolidated,105,,,1050
Qal,Younger alluvium,Holocene,"Alluvium on active flood plains and on lowest terraces of major streams. Chiefly boulders, gravel, and sand.",,,NB004,401,Nabesna,Unconsolidated,105,,,1050
Qa,Alluvium in streams,Holocene and Pleistocene,"Includes alluvium in active flood plains and in principal terraces of major and some minor streams. Chiefly stratified silt, sand, gravel, and boulders.",,,VA007,22,Valdez,Unconsolidated,105,,,1050
Qal,Young alluvial deposits - Alluvium,"Quaternary, Holocene","Alluvium underlying active flood plains and low terraces of major and some minor streams. Chiefly pebble to cobble gravel, and sand. Some small deposits are finer grained and include silt, sand, and gravel",,,GU101,101,Gulkana,Unconsolidated,105,,,1050
Qal,"Alluvium, Modern coarse-grained stream alluvium","Quaternary, Holocene","Active flood plains and lower terraces of larger streams. Chiefly gravel and sand, some boulders; generally stratified",,,NB108,503,Nabesna,Unconsolidated,105,,,1050
Qalf,"Alluvium, Modern fine-grained stream alluvium","Quaternary, Holocene","Restricted to active flood plains. Chiefly sand and silt, some gravel; generally stratified",,,NB108,504,Nabesna,Unconsolidated,105,,,1050
Qal,Alluvium,Quaternary,"Unconsolidated detritus, chiefly silt, sand, and gravel, that generally is poorly sorted and locally is imbricated",,,MC100,101,McCarthy,Unconsolidated,105,,,1050
Qs,Alluvial and outwash deposits,Holocene,"Mainly fluvial and fluvio-glacial gravel, sand, and mud. Includes smaller areas of talus, glacial, and lacustrine sediments",,,YA002,1,Yakutat,Unconsolidated,100,,,1000
Qs,Alluvial and outwash deposits,Holocene,"Mainly fluvial and fluvio-glacial gravel, sand, and mud. Includes smaller areas of talus, glacial, and lacustrine sediments",,,MS002,1,Mount Saint Elias,Unconsolidated,105,,,1050
Qa,Alluvium,"Quaternary, Holocene","Chiefly well-sorted gravel and sand, minor silt, and boulders in higher terraces along larger streams and active alluvial fans",,,IB003,303,Icy Bay,Unconsolidated,105,,,1050
Qa,Alluvium,"Quaternary, Holocene","Chiefly well-sorted gravel and sand, minor silt, and boulders in higher terraces along larger streams and active alluvial fans",,,BG004,303,Bering Glacier,Unconsolidated,105,,,1050
Qa,Alluvium,"Quaternary, Holocene","Alluvium in active streambed and lowest terraces along larger streams and in active alluvial fans. Chiefly well-sorted gravel and sand, minor silt and boulders",,,YA003,201,Yakutat,Unconsolidated,105,,,1050
Qa,Alluvium,"Quaternary, Holocene","Alluvium in active streambed and lowest terraces along larger streams and in active alluvial fans. Chiefly well-sorted gravel and sand, minor silt and boulders",,,GU003,301,Gulkana,Unconsolidated,105,,,1050
Qa,Alluvium,"Quaternary, Holocene","Alluvium in active streambed and lowest terraces along larger streams and in active alluvial fans. Chiefly well-sorted gravel and sand, minor silt and boulders",,,GU004,401,Gulkana,Unconsolidated,105,,,1050
Qal,Alluvium,"Quaternary, Holocene",Alluvium underlying active flood plains and terraces of major streams. Chiefly gravel and sand,,,NB109,301,Nabesna,Unconsolidated,105,,,1050
Qa,Alluvium,"Quaternary, Holocene","Alluvium in active streambed and lowest terraces along larger streams and in active alluvial fans. Chiefly well-sorted gravel and sand, minor silt and boulders",,,NB007,703,Nabesna,Unconsolidated,105,,,1050
Qaf,Alluvium in fans,Holocene,"Mainly large active fans and cones on steep to gentle slopes. Chiefly poorly stratified boulders, cobbles, gravel, and sand.",,,NB008,802,Nabesna,Unconsolidated,106,,,1060
Qaf,Younger alluvium,Holocene,"Alluvial fans and cones. Chiefly boulders, gravel, and sand. Only larger, better defined cones differentiated from unit Qcu.",,,NB004,402,Nabesna,Unconsolidated,106,,,1060
Qaf,Alluvium in fans,Holocene and Pleistocene,"Mainly large, broad, generally active fans and cones on mountain slopes chiefly along major streams. Chiefly sand, gravel, and boulders.",,,VA007,1,Valdez,Unconsolidated,109,,,1090
Qaf,Young alluvial deposits - Alluvium in fans,"Quaternary, Holocene","Alluvium in fans deposited by active, steep-gradient streams. Mostly pebble and cobble gravel, and sand; locally silt and boulder gravel. Includes some glacial outwash from young phase of Alaskan Glaciation",,,GU101,102,Gulkana,Unconsolidated,106,,,1060
Qoaf,Old alluvial deposits - Alluvium in fans,"Quaternary, Holocene","Alluvium in fans and cones that are not graded to present-day stream levels. Chiefly cobble to pebble gravel, and sand; locally silt, boulder gravel, and organic deposits. Commonly overlain by veneer of younger alluvial and colluvial deposits. Includes glacial outwash, mostly from older phases of Alaskan Glaciation. Three sequences of deposition recognized locally",,,GU101,104,Gulkana,Unconsolidated,106,,,1060
Qaf,"Alluvium, Coarse-grained alluvial fans and cones","Quaternary, Holocene",Chiefly gravel and sand that hve been actively water transported.,,,NB108,505,Nabesna,Unconsolidated,106,,,1060
Qaff,"Alluvium, Fine-grained alluvial fans and cones","Quaternary, Holocene",Usually margins of larger fans; chiefly sand and silt,,,NB108,506,Nabesna,Unconsolidated,106,,,1060
Qaf,Alluvial fans,"Quaternary, Holocene","Alluvial fans and cones; only larger, better defined cones differentiated from Qcu. Chiefly gravel and sand",,,NB109,302,Nabesna,Unconsolidated,106,,,1060
Qc,Colluvial deposits,Holocene and Pleistocene,"Colluvium, undivided",,,NB002,109,Nabesna,Unconsolidated,107,,,1070
Qco,Colluvial deposits,Holocene,"Colluvial deposits, river bluff type",,,GU002,107,Gulkana,Unconsolidated,107,,,1070
Qsw,Slope-wash deposits,Quaternary (Holocene),"Slope wash deposits in northeast part of map. Thought to include: Boulder- to pebble-size, angular rock debris derived from mass wasting of bedrock and overlying moraine deposits along walls of the larger valleys. Includes undifferentiated small landslides, and alluvial and glacial deposits",,,BG002,111,Bering Glacier,Unconsolidated,107,,,1070
Qt,Talus deposits,Holocene,Talus deposits,,,BG002,119,Bering Glacier,Unconsolidated,107,,,1071
Qt,Talus,Holocene,"Talus-- Boulder- to pebble-sized, angular rock debris.",,,CV003,140,Cordova,Unconsolidated,107,,,1071
Qca,"Colluvium, undifferentiated",Holocene and Pleistocene,"Talus, but also includes deposits of small landslides, rock glaciers, and other products of mass-wasting processes, and alluvium in small fans and cones. Poorly sorted silt, sand, gravel, and boulders",,,MC003,202,McCarthy,Unconsolidated,107,,,1070
Qcb,Bluff colluvium,Quaternary,Basin bluff colluvium,,,MC004,403,McCarthy,Unconsolidated,107,,,1072
Qc,"Colluvium, undifferentiated",Holocene and Pleistocene,"Chiefly talus but also includes deposits of small landslides, rock glaciers, and other mass-wasting processes. Chiefly unsorted boulders, cobbles, gravel, and sand.",,,NB008,803,Nabesna,Unconsolidated,107,,,1070
Qcu,Colluvial deposits,Holocene,"Undifferentiated colluvium on valley walls and hill slopes. Chiefly rubble, gravel, sand, silt, and diamicton; typically poorly sorted.",,,NB004,406,Nabesna,Unconsolidated,107,,,1070
Qc,"Colluvium, undifferentiated",Holocene and Pleistocene,"Chiefly talus but includes deposits of small landslides, rock glaciers, and other mass-wasting processes. Generally includes a large proportion of alluvium in small fans and cones and reworked glacial deposits. Cheifly poorly sorted silt, sand, gravel, and boulders.",,,VA007,2,Valdez,Unconsolidated,107,,,1070
Qca,Colluvial deposits - Colluvium and alluvium mixed,"Quaternary, Holocene","Predominantly colluvium but includes a large percentage of alluvium from small streams. Mostly diamicton, gravel, and sand",,,GU101,105,Gulkana,Unconsolidated,107,,,1070
Qcu,Colluvial deposits - River bluffs,"Quaternary, Holocene","Colluvium on river bluffs developed in unconsolidated deposits. Mostly diamicton, sand, gravel, and silt",,,GU101,106,Gulkana,Unconsolidated,107,,,1070
Qc,Colluvial deposits - Undivided,"Quaternary, Holocene","Undivided mass-wastage deposits on moderately steep slopes underlain by bedrock or surficial deposits. Chiefly diamicton, silty gravel, silty rubble, and sand. Most deposits originate by downslope movements such as creep, solifluction, and various types of rapid failure of slopes. Also includes talus, small landslides, small rock glaciers, and small alluvial fans",,,GU101,107,Gulkana,Unconsolidated,107,,,1070
Qcvg,Colluvial deposits - Includes volcanic debris flows,"Quaternary, Holocene and Pleistocene",Colluvium underlying gently to moderately steep slopes mostly on northwestern and northern flanks of Mount Drum above about 1200 m. Includes volcanic debris flows and rocks derived from more easily weathered bedrock locally mixed with glacial deposits of pre-Wisconsin age.,,,GU101,108,Gulkana,Unconsolidated,107,,,1070
Qcu,"Colluvial, undifferentiated","Quaternary, Holocene and Pleistocene","Chiefly talus and slope debris that has not been actively water transported. Includes various minor unconsolidated features. Poorly sorted, silt to boulders",,,NB108,509,Nabesna,Unconsolidated,107,,,1070
Qt,Talus,Quaternary,Widespread elongate lobes and coalescing aprons. Mainly angular rock fragments,,,MC100,102,McCarthy,Unconsolidated,107,,,1071
Qt,Talus deposits,Holocene,"Larger areas of poorly sorted, angular deposits forming cones and aprons at the base of steep slopes",,,YA002,15,Yakutat,Unconsolidated,107,,,1071
Qu,"Slope deposits, undifferentiated","Quaternary, Holocene and Pleistocene","Sand, gravel, boulders, diamicton, and rubble colluvium (talus and small landslides), but may also include small glacial, rock glacier, and alluvial deposits",,,BG004,301,Bering Glacier,Unconsolidated,107,,,1070
tan,Talus,"Quaternary, Holocene",Talus,,,CV005,503,Cordova,Unconsolidated,107,,,1071
tan,Talus,"Quaternary, Holocene",Talus,,,CV006,503,Cordova,Unconsolidated,107,,,1071
Qcb,Bluff colluvium,"Quaternary, Holocene","Colluvium along the high steep bluffs of the Copper River and its principal tributaries. Includes numerous local exposures of Copper River deposits (unit Qcr) and drift of older glaciations (unit Qg). Unsorted silt, sand, gravel, and boulders",,,GU003,305,Gulkana,Unconsolidated,107,,,1072
Qcb,Bluff colluvium,"Quaternary, Holocene","Colluvium along the high steep bluffs of the Copper River and its principal tributaries. Includes numerous local exposures of Copper River deposits (unit Qcr) and drift of older glaciations (unit Qg). Unsorted silt, sand, gravel, and boulders",,,GU004,402,Gulkana,Unconsolidated,107,,,1072
Qcu,Colluvium undifferentiated,"Quaternary, Holocene","Undifferentiated colluvium on valley walls and hill slopes. Chiefly talus and other slope debris but includes alluvium of numerous minor streams and locally, glacial, rock glacier, and other mass-wasting deposits. Chiefly rubble, gravel, sand, and silt; usually poorly sorted. May overlie and include extensive glacial deposits (Qwg) in broad valleys",,,NB109,304,Nabesna,Unconsolidated,107,,,1070
Qcb,Bluff colluvium,"Quaternary, Holocene","Colluvium along the high steep bluffs of the Copper River and its principal tributaries. Includes numerous local exposures of Copper River deposits (unit Qcr) and drift of older glaciations (unit Qg). Unsorted silt, sand, gravel, and boulders",,,NB007,715,Nabesna,Unconsolidated,107,,,1072
Ql,Colluvial deposits,Holocene,Landslide deposits,,,NB002,108,Nabesna,Unconsolidated,108,,,1080
Qls,Landslide deposits,Holocene,"Larger deposits of unsorted, angular rock debris derived by massive failure of steep bedrock slopes.",,,BG002,120,Bering Glacier,Unconsolidated,108,,,1080
Qls,Landslides,Holocene,"Landslides-- Unsorted, angular rock debris derived by failure of bedrock slopes.",,,CV003,145,Cordova,Unconsolidated,108,,,1080
Ql,Landslide deposits,Holocene and Pleistocene,Includes large slump and debris avalanche deposits. Particularly common along steep north flank of mountain escarpment south of Beaver Creek. Slump deposits consist chiefly of masses of volcanic rock as much as hundreds of meters wide; deposits are chiefly diamicton and rubble,,,MC003,204,McCarthy,Unconsolidated,108,,,1080
Ql,Landslide deposits,Quaternary,Landslide deposits,,,MC004,404,McCarthy,Unconsolidated,108,,,1080
Qls,Landslide deposits,Holocene,Larger landslides; arrows show downslope movement direction.,,,MS002,17,Mount St. Elias,Unconsolidated,108,,,1080
Qcl,Colluvial deposits,Holocene,Colluvial deposits. Young landslide deposits. Chiefly debris avalanches.,,,NB004,405,Nabesna,Unconsolidated,108,,,1080
Qls,Landslide deposits,"Quaternary, Holocene and Pleistocene","Landslide deposits of all types, including slumps, block glides, earthslides, debris slides and flows, debris avalanches, and rockfalls; includes massive slump deposits within volcanic avalanche deposits (Qva) in Nadina River and nearby valleys. May include some rock-glacier deposits",,,GU101,109,Gulkana,Unconsolidated,108,,,1080
Qcl,"Colluvial, landslide deposits","Quaternary, Holocene and Pleistocene",Yound fresh debris avalanches. Chiefly coarse rubbly diamicton,,,NB108,508,Nabesna,Unconsolidated,108,,,1080
Qls,Landslide deposits,Holocene,Larger landslides; arrows show downslope movement direction.,,,YA002,17,Yakutat,Unconsolidated,108,,,1080
Ql,Landslide deposits ,"Quaternary, Holocene and Pleistocene","Includes slumps, earth-debris flows, block glides, and debris avalanches. Diamicton and rubble",,,GU003,307,Gulkana,Unconsolidated,108,,,1080
Ql,Landslide deposits ,"Quaternary, Holocene and Pleistocene","Includes slumps, earth-debris flows, block glides, and debris avalanches. Diamicton and rubble",,,NB007,701,Nabesna,Unconsolidated,108,,,1080
Qc,Conglomerate,Pleistocene,"Conglomerate, fluvial deposits derived from Wrangell Lava and deposited on unit QTu, undifferentiated volcanic rocks and older, pre-Wrangell rocks",,,GU002,112,Gulkana,Sedimentary,109,,,1090
Qao,Older alluvium,Quaternary,Older alluvium in larger streams and fans,,,MC004,401,McCarthy,Unconsolidated,109,,,1090
Qoa,Older alluvium,Holocene,"Deposits in higher terraces along major streams and in old dissected alluvial fans. Chiefly boulders, gravel, and sand.",,,NB004,407,Nabesna,Unconsolidated,109,,,1090
Qoa,Older alluvium,Pleistocene,"Chiefly sand, gravel, and boulders; may include some diamicton. Maximum thickness about 150m.",,,VA007,28,Valdez,Unconsolidated,109,,,1090
Qoa,Old alluvial deposits,"Quaternary, Holocene","Alluvium underlying intermediate and high terraces near major streams. Chiefly pebble to cobble gravel, and sand. Includes glacial outwash from various phases of Alaskan Glaciation. Four sequences of deposition recognized on outwash flood plains below termini of Nadina, West Drum, and Northwest Drum Glaciers",,,GU101,103,Gulkana,Unconsolidated,109,,,1090
Qao,Old alluvial deposits,"Quaternary, Holocene",Mapped on higher terraces along larger streams; probably related to the older phase of the Alaskan Glaciation. Chiefly gravel and sand,,,NB108,507,Nabesna,Unconsolidated,109,,,1090
Qoa,Older alluvium,Quaternary,"Benches and terraces that support vegetation along ancestral flood plains. Unconsolidated detritus, chiefly silt, sand, and gravel, that generally is poorly sorted and locally is imbricated",,,MC100,103,McCarthy,Unconsolidated,109,,,1090
Qao,Older alluvium,"Quaternary, Holocene and Pleistocene","Chiefly well-sorted gravel and sand, also minor silt, and boulders in higher terraces along larger streams and inactive alluvial fans. Predominantly of Pleistocene age, may include localized Holocene deposits",,,IB003,305,Icy Bay,Unconsolidated,109,,,1090
Qao,Older alluvium,"Quaternary, Holocene and Pleistocene","Chiefly well-sorted gravel and sand, also minor silt, and boulders in higher terraces along larger streams and inactive alluvial fans. Predominantly of Pleistocene age, may include localized Holocene deposits",,,BG004,305,Bering Glacier,Unconsolidated,109,,,1090
Qao,Older alluvium,"Quaternary, Holocene and Pleistocene","Alluvium in higher terraces along larger streams and in inactive alluvial fans. Chiefly well-sorted gravel and sand, minor silt and boulders. Predominantly of Pleistocene age, localized deposits include the Holocene",,,YA003,202,Yakutat,Unconsolidated,109,,,1090
Qao,Older alluvium,"Quaternary, Holocene and Pleistocene","Alluvium in higher terraces along larger streams and in inactive alluvial fans. Chiefly well-sorted gravel and sand, minor silt and boulders. Predominantly of Pleistocene age, localized deposits include the Holocene",,,GU003,303,Gulkana,Unconsolidated,109,,,1090
Qao,Older alluvium,"Quaternary, Holocene and Pleistocene","Alluvium in higher terraces along larger streams and in inactive alluvial fans. Chiefly well-sorted gravel and sand, minor silt and boulders. Predominantly of Pleistocene age, localized deposits include the Holocene",,,GU004,403,Gulkana,Unconsolidated,109,,,1090
Qao,Older alluvium,"Quaternary, Holocene and Pleistocene","Alluvium in higher terraces along larger streams and in inactive alluvial fans. Chiefly well-sorted gravel and sand, minor silt and boulders. Predominantly of Pleistocene age, localized deposits include the Holocene",,,NB007,711,Nabesna,Unconsolidated,109,,,1090
Qfl,Fluviolacustrine deposits,Holocene and Pleistocene,"Deposits of lakes, ponds, and low-gradient streams. Sand, silt, and clay",,,NB002,102,Nabesna,Unconsolidated,112,,,1120
Qgl,Glaciolacustrine deposits,Pleistocene,"Deposits of glacial lakes. Clay, silt, sand, and minor gravel",,,NB002,103,Nabesna,Unconsolidated,112,,,1120
Qfl,Fluviolacustrine and swamp deposits,Quaternary,"Mud, clay and peat",,,MC004,402,McCarthy,Unconsolidated,112,,,1120
Qfl,Fine-grained deposits,"Quaternary, Holocene","Chiefly silt, clay, fine sand, peat, and other organic material in ponds, swamps, lagoons, and along low-gradient streams",,,BG004,311,Bering Glacier,Unconsolidated,112,,,1120
lt green,Recent Lacustrine deposits,"Quaternary, Holocene",Lacustrine deposits,,,CV005,501,Cordova,Unconsolidated,112,,,1120
lt green,Recent Lacustrine deposits,"Quaternary, Holocene",Lacustrine deposits,,,CV006,501,Cordova,Unconsolidated,112,,,1120
Qfl,Fine-grained deposits ,"Quaternary, Holocene","In ponds, swamps, lagoons, and along low-gradient streams. Chiefly silt, clay, fine sand, peat and other organic material ",,,GU003,311,Gulkana,Unconsolidated,112,,,1120
Qfl,Fine-grained deposits ,"Quaternary, Holocene","In ponds, swamps, lagoons, and along low-gradient streams. Chiefly silt, clay, fine sand, peat and other organic material ",,,NB007,707,Nabesna,Unconsolidated,112,,,1120
Qb,Beaches and spits,Holocene,Constructional shoreline deposits of well-sorted gravel and sand formed as spits extending westward or northwestward from headlands and beaches consisting of successive sequences of marshes and ridges extending landward from the present shoreline.,,,BG002,115,Bering Glacier,Unconsolidated,115,,,1150
Qb,"Beaches, spits, and offshore bars",Holocene,"Beaches, spits, and offshore bars -- Constructional shoreline deposits of well-sorted gravel and sand.",,,CV003,115,Cordova,Unconsolidated,115,,,1150
Qb,Beach,Quaternary,Wave deposited sand and gravel.,,,MC004,412,McCarthy,Unconsolidated,115,,,1150
Qb,Marine shoreline deposits,Holocene,"Mainly sand and gravel of present and former beaches, beach ridges, beach bars and spits. Includes smaller sand dunes",,,YA002,7,Yakutat,Unconsolidated,115,,,1150
Qb,Beaches and spits,Holocene,Constructional shoreline deposits of well-sorted gravel and sand formed as spits extending westward or northwestward from headlands and beaches consisting of successive sequences of marshes and ridges extending landward from the present shoreline.,,,IB002,115,Icy Bay,Unconsolidated,115,,,1150
Ql,Lagoonal deposits,Holocene,"Intertidal mud and sand deposited in swamp areas between beach ridges and in tidal embayments, single polygon at toe of Malaspina Glacier",,,IB002,121,Icy Bay,Unconsolidated,116,,,1160
Ql,Lagoonal deposits,Holocene,"Lagoonal deposits--Fine-grained silt rich in organic material, mud, and peat.",,,CV003,120,Cordova,Unconsolidated,116,,,1160
Ql,Lagoonal deposits,Holocene,Intertidal mud and sand deposited in swamp areas between beach ridges and in tidal embayments,,,YA002,3,Yakutat,Unconsolidated,116,,,1160
Qms,Mineral spring and mud volcano deposits,Holocene and Pleistocene,Mineral spring and mud volcano deposits,,,GU002,108,Gulkana,Unconsolidated,118,,,1180
Qme,Mineral spring deposits,Quaternary,Chiefly mud,,,MC004,409,McCarthy,Unconsolidated,118,,,1180
Qsm,Mineral spring and mud volcano deposits,"Quaternary, Holocene and Pleistocene","Upper Klawasi Mud Volcano cone. Chiefly silt and clay deposited by mud-rich, relatively warm Na-Cl-HCO3 springs; includes some glacial drift deposits",,,GU101,122,Gulkana,Unconsolidated,118,,,1180
Qms,Mineral spring deposits ,"Quaternary, Holocene","Chiefly mud (clayey silt) deposited by warm, Na-HCO3-rich saline water charged with CO2 from 3 active springs (Klawasi mud volcanoes) west of Mt. Drum and at least one inactive spring west of Capital Mountain. Unit also includes the Copper Center spring, a methane-charged spring, on the east bank of the Copper River near Copper Center",,,GU003,331,Gulkana,Unconsolidated,118,,,1180
Qe,Eolian deposits,Holocene,"Dune, and remnant sand dune, deposits. Sand and silt",,,NB002,110,Nabesna,Unconsolidated,120,,,1200
Qds,Active cliff-head dune deposits,Holocene,Active cliff-head dune deposits,,,GU002,105,Gulkana,Unconsolidated,120,,,1200
Qd,Dunes,Holocene,Well-sorted fine-to medium-grain sand with abundant driftwood and sparse pebbles along the coast south of Bering Glacier. Dunes are nourished by prevailing southeasterly storm winds that blow across outwash deposits of the Bering Glacier.,,,BG002,114,Bering Glacier,Unconsolidated,120,,,1200
Qd,Dunes,Holocene,"Dunes-- Well sorted, fine grained sand and silt aligned in longitudinal ridges.",,,CV003,125,Cordova,Unconsolidated,120,,,1200
Qe,Eolian/Dune,Quaternary,Sand dunes,,,MC004,411,McCarthy,Unconsolidated,120,,,1200
Qd,Dunes,Holocene,Larger sand dunes associated with present beaches and streams,,,YA002,5,Yakutat,Unconsolidated,120,,,1200
Qd,Dunes,Holocene,Well-sorted fine-to medium-grain sand with abundant driftwood and sparse pebbles along the coast south of Bering Glacier. Dunes are nourished by prevailing southeasterly storm winds that blow across outwash deposits of the Bering Glacier.,,,IB002,114,Icy Bay,Unconsolidated,120,,,1200
Qd,Deltaic deposits,"Quaternary, Holocene",Associated with higher lake levels during the Alaskan Glaciation. Sand and gravel,,,NB108,502,Nabesna,Unconsolidated,123,,,1230
Ql,Lacustrine deposits,Late Pleistocene,Lacustrine deposits,,,GU002,109,Gulkana,Unconsolidated,124,,,1240
Qgl,Glaciolacustrine deposit,Quaternary,Interbedded lake and glacial deposits of the Copper River basin,,,MC004,408,McCarthy,Unconsolidated,124,,,1240
Qgl,Drift of Wisconsin Glaciation - Glaciolacustrine,"Quaternary, Pleistocene","Glaciolacustrine deposits on floor and sloping shore areas of glacial Lake Atna. Mostly clayey silt and silty fine sand; locally pebbly silt. Sand and pebble gravel near shorelines, especially close to 745 m elevation",,,GU101,121,Gulkana,Unconsolidated,124,,,1240
Ql,Lacustrine deposits,"Quaternary, Holocene and Pleistocene",Pond and lake sediments - Deposits associated with high lake levels during the Alaskan Glaciation. Others from small ponds and commonly covered with peat. Chiefly clay and silt,,,NB108,501,Nabesna,Unconsolidated,124,,,1240
Qgf,Glaciofluvial deposits,Quaternary,"The glaciofluvial deposits, broadly distributed below 900 m in elevation, are, in part, products of intermittent deposition in a large periglacial Pleistocene lake that occupied extensive parts of the Chitina Valley and Copper River Basin. Also included are proglacial deltaic and similar lake margin deposits. Most weather to light brown or tan and are poorly consolidated, poorly sorted, and crudely stratified. Boulder-cobble rich gravels, with local dominations of sand and silt.",,,MC100,107,McCarthy,Unconsolidated,124,,,1240
Qcr,"Copper River deposits, undifferentiated ","Quaternary, Pleistocene","Interbedded glaciolacustrine, glacial, and alluvial deposits including those of glacial Lake Atna at the surface. Chiefly clayey to pebbly silt and diamicton, with many local to regional beds of gravel and sand. Locally overlain by fine-grained alluvium and pond deposits (map unit Qfl) in areas too small to show separately ",,,NB007,705,Nabesna,Unconsolidated,124,,,1240
Qlg,"Deposits of the Copper River Basin, undifferentiated",Pleistocene,"Chiefly diamicton interbedded with stratified lacustrine sediments. The diamicton interbedded in the lake sediments ranges from non-sorted till to deposits of poorly sorted material that exhibits graded bedding. The lake sediments, consisting of sand, silt, and clay, locally contain ice-rafted dropstones. Diamiction, gravel, sand, silt, and clay. ",,,VA007,23,Valdez,Unconsolidated,124,,,1240
Qm,Moraines,Quaternary,"Lateral, end, and a few ground moraines that are relics of extensive glaciation. They consist of jumbled boulders with broad ranges in size and composition. Older moraines are weathered and support vegetation",,,MC100,104,McCarthy,Unconsolidated,125,,,1250
lime,Older glacial deposits,"Quaternary, Holocene and Pleistocene",Glacial deposits,,,CV006,511,Cordova,Unconsolidated,125,,,1250
Qsm,Supraglacial moraine,Holocene,"Unweathered, poorly sorted, pebble- to boulder sized rock debris on surfaces of alpine and valley glaciers.",,,BG002,116,Bering Glacier,Unconsolidated,126,,,1260
Qsm,Supraglacial moraine,Holocene,"Supraglacial moraine-- Unweathered, poorly sorted, debris on surfaces of glaciers.",,,CV003,130,Cordova,Unconsolidated,126,,,1260
Qsm,Supraglacial deposits,Holocene,Unsorted angular debris ranging in size from silt to blocks on surfaces of the present glaciers.,,,MS002,9,Mount Saint Elias,Unconsolidated,126,,,1260
Qaga,Drift of Alaskan Glaciation - Ablation moraines,"Quaternary, Holocene",Chiefly ablation moraine on existing glaciers. Largely rubble and diamicton underlain by glacier ice,,,GU101,111,Gulkana,Unconsolidated,126,,,1260
Qmi,Moraines on ice,Quaternary,Moraines on ice that mantle active glaciers. Dominantly fresh boulders and form veneers,,,MC100,105,McCarthy,Unconsolidated,126,,,1260
Qsm,Supraglacial deposits,Holocene,Unsorted angular debris ranging in size from silt to blocks on surfaces of the present glaciers.,,,YA002,9,Yakutat,Unconsolidated,126,,,1260
Qsm,Supraglacial moraine,Holocene,"Unweathered, poorly sorted, pebble- to boulder sized rock debris on surfaces of alpine and valley glaciers.",,,IB002,116,Icy Bay,Unconsolidated,126,,,1260
Stipple,Superglacial drift,Quaternary,Rock debris on existing glaciers,,,GU003,319,Gulkana,Unconsolidated,126,,,1260
Qsg,Superglacial Drift,Quaternary,Superglacial Drift,,,NB007,717,Nabesna,Unconsolidated,126,,,1260
Qr,Rock glacier deposits,Holocene,"Tallis and deposits from recently active, and recently active, rock glaciers. Rubble and diamicton",,,NB002,107,Nabesna,Unconsolidated,127,,,1270
Qrg,Rock glaciers,Holocene,"Unweathered, poorly sorted, pebble- to boulder sized rock debris and ice",,,BG002,112,Bering Glacier,Unconsolidated,127,,,1270
Qrg,Rock glacier deposits,Holocene,Deposits of active rock glaciers exhibiting well-defined lobate form. Chiefly angular blocks and diamicton,,,MC003,205,McCarthy,Unconsolidated,127,,,1270
Qrg,Rock glacier deposit,Quaternary,Rock glacier deposit,,,MC004,407,McCarthy,Unconsolidated,127,,,1270
Qrg,Rock glacier deposits,Holocene and Pleistocene,Deposits in bith active rock glaciers and inactive rock glaciers. Chiefly angular blocks and diamicton.,,,NB008,804,Nabesna,Unconsolidated,127,,,1270
Qrg,Rock glacier deposits,Holocene,Active and recently active rock glaciers. Chiefly rubble and diamiction.,,,NB004,404,Nabesna,Unconsolidated,127,,,1270
Qr,Rock glacier deposits,Holocene,Chiefly angular blocks and diamicton.,,,VA007,11,Valdez,Unconsolidated,127,,,1270
Qrg,Rock glacier deposits,"Quaternary, Holocene","Includes deposits that are active or were recently active in generally well defined lobate forms, and deposits of old, generally inactive, rock glaciers with less well defined and commonly smooth margins. Chiefly rubble and diamicton",,,GU101,110,Gulkana,Unconsolidated,127,,,1270
Qrg,Rock glaciers,"Quaternary, Holocene",Diamicton of active rock glaciers,,,NB108,510,Nabesna,Unconsolidated,127,,,1270
Qrg,Rock glaciers,Quaternary,Hummocky lobate masses consisting of disarrayed angular and blocky boulders and smaller rocks that are partly cemented by ice,,,MC100,106,McCarthy,Unconsolidated,127,,,1270
Qrg,Rock glacier deposits,"Quaternary, Holocene",Chiefly blocks of rubble lying on buried glaciers exhibiting well-defined lobate forms. May or may not include glacier cores at depth,,,BG004,307,Bering Glacier,Unconsolidated,127,,,1270
Qrg,Rock Glacier deposits,"Quaternary, Holocene","Includes deposits of active, recently active, and formerly active rock glaciers. Chiefly rubble and diamicton",,,NB109,303,Nabesna,Unconsolidated,127,,,1270
Qs,Solifluction deposits,Holocene and Pleistocene,"Deposits on low-angle, low-relief slopes at relatively high elevations. Mostly bedrock rubble but may include some Wisconsin and older glacial drift",,,MC003,203,McCarthy,Unconsolidated,128,,,1280
Qs,Solifluction and older glacial deposits,"Quaternary, Holocene and Pleistocene","Deposits on low-angle, low-relief slopes, at high elevation. Mostly bedrock rubble, but includes some glacial drift. Some of Qs was probably covered by Wisconsin ice, whereas all of Qs was covered by pre-Wisconsin ice",,,NB108,511,Nabesna,Unconsolidated,128,,,1280
Qu,"Slope deposits, undifferentiated ","Quaternary, Holocene and Pleistocene","Chiefly colluvium (talus and small landslides) but may include local glacial, rock glacier, and alluvial deposits. Sand, gravel, boulders, diamicton, and rubble",,,GU003,313,Gulkana,Unconsolidated,107,,,1070
Qs,Colluvial - Solifluction,"Quaternary, Holocene",Solifluction and creep surfaces on high-level low-gradient slopes. Chiefly bedrock rubble but may include older glacial drift deposits,,,NB109,305,Nabesna,Unconsolidated,128,,,1280
Qu,"Slope deposits, undifferentiated ","Quaternary, Holocene and Pleistocene","Chiefly colluvium (talus and small landslides) but may include local glacial, rock glacier, and alluvial deposits. Sand, gravel, boulders, diamicton, and rubble",,,NB007,713,Nabesna,Unconsolidated,107,,,1070
Qwfe,Drift of Wisconsin Glaciation - Eskers,"Quaternary, Pleistocene",Prominent eskers. Chiefly gravel and some sand,,,GU101,116,Gulkana,Unconsolidated,129,,,1290
Qag,Glacial deposits,Holocene,Drift of Alaskan Glaciation. End and lateral moraine deposits of receding glaciers. Rubble and diamicton,,,NB002,106,Nabesna,Unconsolidated,130,,,1300
Qm,Younger glacial moraine,Holocene,"Undifferentiated terminal, lateral, and ground moraine. Locally includes and kame and esker deposits of Guyot Glacier around Icy Bay.",,,BG002,117,Bering Glacier,Unconsolidated,130,,,1300
Qm,"Terminal, lateral, and ground moraine",Holocene,"Terminal, lateral and ground moraine-- Unsorted boulders, cobbles, gravel and sand deposited during retreat of glaciers.",,,CV003,135,Cordova,Unconsolidated,130,,,1300
Qag,Alaskan glaciation deposits,Holocene,Terminal and lateral moraine at base of small ice field. Chiefly diamicton,,,MC003,199,McCarthy,Unconsolidated,130,,,1300
Qag,Alaskan glaciation deposits,Quaternary,Drift of Alaska glaciation ,,,MC004,405,McCarthy,Unconsolidated,130,,,1300
Qm,"Younger end, ground, and lateral moraine deposits",Holocene,"Mainly till, but locally includes lacustrine and glaciofluvial deposits. Arrow indicates direction of ice movement as inferred from trend of elongate trenches and ridges. Advance of Hubbard Glacier culminated in Yakutat Bay between 1700 and 1791 A.D.",,,MS002,11,Mount Saint Elias,Unconsolidated,130,,,1300
Qag,Drift of Alaskan glaciation,Holocene,"End, lateral, and ground moraine of the Alaskan glaciations which were deposited during the recession of existing glaciers. Diamicton and rubble; local gravel and sand.",,,NB008,805,Nabesna,Unconsolidated,130,,,1300
Qam,Drift of the Alaskan Glaciation,Holocene,Drift of the Alaskan GlaciationChiefly rubble and diamicton.,,,NB004,403,Nabesna,Unconsolidated,130,,,1300
Qag,Drift of Alaskan glaciation,Holocene,"Includes end and lateral moraines of the younger and older phases of Alaska glaciation, deposited after recession of existing glaciers. Diamiction, local gravel, and sand.",,,VA007,15,Valdez,Unconsolidated,130,,,1300
Qag,Drift of Alaskan Glaciation - Younger phase,"Quaternary, Holocene","Mostly end and lateral moraines, including some ground moraine, generally in front of existing glaciers. Rubble, diamicton, and some gravel and sand. May include some rock glaciers and drift of the old phase of Alaskan Glaciation",,,GU101,112,Gulkana,Unconsolidated,130,,,1300
Qoag,Drift of Alaskan Glaciation - Older phase,"Quaternary, Holocene","Mostly end and lateral moraines, locally in front of rock glaciers. Chiefly diamicton and rubble; some gravel and sand. Covered in places by colluvial deposits",,,GU101,113,Gulkana,Unconsolidated,130,,,1300
Qam,Glacial deposits of the Alaskan Glaciation,"Quaternary, Holocene",Ablation and termianl moraines directly related to existing glaciers; may include some older deposits. Mostly rubbly till,,,NB108,512,Nabesna,Unconsolidated,130,,,1300
Qm,"Younger end, ground, and lateral moraine deposits",Holocene,"Mainly till, but locally includes lacustrine and glaciofluvial deposits. Arrow indicates direction of ice movement as inferred from trend of elongate trenches and ridges. Advance of Hubbard Glacier culminated in Yakutat Bay between 1700 and 1791 A.D.",,,YA002,11,Yakutat,Unconsolidated,130,,,1300
Qmo,"Older end, ground, and lateral moraine deposits",Holocene,Glaciomarine till and till associated with a neoglacial advance of the Hubbard Glacier system which culminated in Yakutat Bay between 970 and 1290 A.D.,,,YA002,13,Yakutat,Unconsolidated,130,,,1301
Qm,Younger glacial moraine,Holocene,"Undifferentiated terminal, lateral, and ground moraine. Locally includes and kame and esker deposits of Guyot Glacier around Icy Bay.",,,IB002,117,Icy Bay,Unconsolidated,130,,,1300
Qmo,Older glacial moraine,Holocene,"Undifferentiated terminal, lateral, and ground moraine of Guyot Glacier around Icy Bay.",,,IB002,118,Icy Bay,Unconsolidated,130,,,1300
Qag,Drift of Alaskan (Neoglacial) glaciation,"Quaternary, Holocene","Diamicton, local gravel, and sand in end, lateral, and ground moraines, kames, and outwash proximal to present glaciers; includes small rock glaciers",,,BG004,309,Bering Glacier,Unconsolidated,130,,,1300
tan,"Glacial deposits, undivided","Quaternary, Holocene",Glacial deposits,,,CV005,504,Cordova,Unconsolidated,130,,,1300
tan,"Younger glacial deposits, undivided","Quaternary, Holocene",glacial deposits ,,,CV006,510,Cordova,Unconsolidated,130,,,1300
Qag,Drift of Alaskan (Neoglacial) glaciation ,"Quaternary, Holocene","End, lateral, and ground moraine and kames and outwash proximal to present glaciers. Includes rock glaciers too small to map. Diamicton, local gravel and sand",,,GU003,309,Gulkana,Unconsolidated,130,,,1300
Qam,Drift of Alaskan Glaciation,"Quaternary, Holocene",Chiefly end and lateral moraines of the stade of the Alaskan Glaciation. Diamicton and rubble; local gravel,,,NB109,306,Nabesna,Unconsolidated,130,,,1300
Qag,Drift of Alaskan (neoglacial) glaciation ,"Quaternary, Holocene (neoglacial)","End, lateral, and ground moraine and kames and outwash proximal to present glaciers. Includes rock glaciers too small to map. Diamicton, local gravel and sand",,,NB007,722,Nabesna,Unconsolidated,130,,,1300
Qoal,Older alluvium,Holocene and Pleistocene,"Mainly outwash related to Alaskan glaciation and possibly younger phase of Wisconsin glaciation. Stratified silt, sand, gravel, and boulders.",,,MC003,201,McCarthy,Unconsolidated,131,,,1310
Qwg,Glacial deposits,Pleistocene,"Drift of Wisconsin glaciation. End, lateral, and ground moraine and fluvialglacial deposits.",,,NB002,104,Nabesna,Unconsolidated,135,,,1350
Qwl,Younger Wisconsin glaciation deposits,Pleistocene,Terminal and lateral moraines of late(?) phase of Wisconsin glaciation. Chiefly diamicton and rubble,,,MC003,206,McCarthy,Unconsolidated,135,,,1350
Qog,Older glaciation deposits,Quaternary,Drift of older glaciations. Includes lake deposits in the Chitina River valley.,,,MC004,406,McCarthy,Unconsolidated,135,,,1350
Qwg,Drift of Wisconsin glaciation,Pleistocene,Drift of Wisconsin glaciation. Chiefly lateral and ground moraine of both younger and older stages of Wisconsin glaciation. Diamicton and rubble; local gravel and sand.,,,NB008,806,Nabesna,Unconsolidated,135,,,1350
Qog,Drift of older glaciations,Pleistocene,"Drift of Wisconsin glaciation. Chiefly diamicton; local sand, gravel and boulders.",,,NB008,807,Nabesna,Unconsolidated,135,,,1350
Qlo,Drift of Late Wisconsin age,Pleistocene,Drift of Late Wisconsin ageWell-defined outwash fan. Chiefly gravel and sand.,,,NB004,408,Nabesna,Unconsolidated,135,,,1350
Qld,Drift of Late Wisconsin age,Pleistocene,"Drift of Late Wisconsin ageGround moraine, chiefly diamiction. Includes minor fluvioglacial deposits of gravel and sand and scattered pond and fine-grained alluvial deposits of sand, silt, and clay.",,,NB004,409,Nabesna,Unconsolidated,135,,,1350
Qmd,Drift of Main Wisconsin age,Pleistocene,"Drift of Main Wisconsin ageGround moraine, chiefly diamicton.",,,NB004,410,Nabesna,Unconsolidated,135,,,1350
Qog,Drift of Older Glaciations,Pleistocene,Drift of Older GlaciationsChiefly diamicton and boulder deposits.,,,NB004,411,Nabesna,Unconsolidated,135,,,1350
Qyg,Drift of younger (Wisconsin) glaciation,Pleistocene,"Well defined lateral moraines high on the valley walls of the Dadina, Chetaslina, and East Fork of the Chetaslina Rivers. Diamicton.",,,VA007,21,Valdez,Unconsolidated,135,,,1350
Qwmc,Drift of Wisconsin Glaciation - Channeled ground moraine,"Quaternary, Pleistocene","Area of drift deposits, mainly ground moraine, extensively channeled and eroded by glacier melt-water streams. Channels contain some gravel and sand, overlain in many places by silty organic deposits",,,GU101,117,Gulkana,Unconsolidated,135,,,1350
Qwm,Drift of Wisconsin Glaciation - Ground moraine,"Quaternary, Pleistocene","Drift, mostly gently rolling to undulating ground moraine exhibiting some linear and few drumlinoidal ridges. Includes outwash in channels cut into drift by glacier melt-water streams and some ice-contact deposits, lateral moraines, and colluvial deposits. Ponds numerous locally. Chiefly diamicton. In channels, swales and some ridges, gravel and sand; near ponds, silty organic deposits",,,GU101,118,Gulkana,Unconsolidated,135,,,1350
Qwml,Drift of Wisconsin Glaciation - Lateral moraines,"Quaternary, Pleistocene",Mostly lateral moraines perched along valley walls. Chiefly diamicton and rubble.,,,GU101,119,Gulkana,Unconsolidated,135,,,1350
Qwme,Drift of Wisconsin Glaciation - End moraines,"Quaternary, Pleistocene","Principally complexes of end with some lateral moraines; includes some ground-moraine and ice-contact deposits. Chiefly diamicton, with some gravel, sand, and silty organic deposits",,,GU101,120,Gulkana,Unconsolidated,135,,,1350
Qlm,Glacial deposits of the late Wisconsin,"Quaternary, Pleistocene","Old terminal, lateral, and ground moraines. Chiefly till",,,NB108,513,Nabesna,Unconsolidated,135,,,1350
Qmm,Glacial deposits of the main Wisconsin Glaciation,"Quaternary, Pleistocene",Chiefly ground and lateral moraines. Includes drumlinoid features. Chiefly till,,,NB108,514,Nabesna,Unconsolidated,135,,,1350
Qg,Drift of older glaciations,"Quaternary, Pleistocene","Chiefly diamicton, local gravel, and sand in end, lateral, and ground moraines of Wisconsin and older glaciations. Locally includes kames, kame-like deposits and outwash. Also includes glaciolacustrine deposits (Qcr) near the complex interface with Glacial Lake Atna in the lower Chitna River valley",,,BG004,313,Bering Glacier,Unconsolidated,135,,,1350
Qg,Drift of older glaciations,"Quaternary, Pleistocene","Chiefly diamicton, local gravel, and sand in end, lateral, and ground moreanie of Wisconsin and older glaciations. Locally includes kames, kame-like deposits, and outwash.",,,YA003,14,Yakutat,Unconsolidated,135,,,1350
Qg,Drift of older glaciations ,"Quaternary, Pleistocene","End, lateral, and ground moraine of Wisconsin and older glaciations. Locally includes kame and kame-like deposits and outwash. The Chitina River valley includes glaciolacustrine deposits near the complex interface with glacial Lake Atna. Chiefly diamicton, local gravel and sand",,,GU003,321,Gulkana,Unconsolidated,135,,,1350
Qwm ,Drift of Wisconsin Age - Moraines,"Quaternary, Pleistocene",Well-defined lateral moraines of the late Wisconsin age. Chiefly diamicton,,,NB109,307,Nabesna,Unconsolidated,135,,,1350
Qwg,Drift of Wisconsin Age - Undifferentiated,"Quaternary, Pleistocene","Undifferentiated glacial, fluvioglacial, and volcanoglacial deposits. Probably represent more than one episode of Wisconsin Glaciation. Chiefly diamicton and sand and gravel",,,NB109,308,Nabesna,Unconsolidated,135,,,1350
Qg,Drift of older glaciations ,"Quaternary, Pleistocene","End, lateral, and ground moraine of Wisconsin and older glaciations. Locally includes kame and kame-like deposits and outwash. The Chitina River valley includes glaciolacustrine deposits near the complex interface with glacial Lake Atna. Chiefly diamicton, local gravel and sand",,,NB007,709,Nabesna,Unconsolidated,135,,,1350
Qwg,Older Wisconsin glaciation deposits,Pleistocene,"Ground moraine of main(?) phase of Wisconisin glaciation. Diamicton, local gravel and sand",,,MC003,209,McCarthy,Unconsolidated,138,,,1380
Qwo,Fluvio-glacial deposits,"Quaternary, Pleistocene","Outwash related to main(?) phase of Wisconsin glaciation. Silt, sand, gravel, and boulders",,,MC003,208,McCarthy,Unconsolidated,140,,,1400
Qwo,Drift of Wisconsin Glaciation - Outwash,"Quaternary, Pleistocene","Outwash probably of main phase of glaciation. Located in well-defined plains and broad channels; surface pitted in places. Chiefly well bedded gravel and sand, mantled locally by organic silt",,,GU101,114,Gulkana,Unconsolidated,140,,,1400
Qwf,Drift of Wisconsin Glaciation - Fluvioglacial,"Quaternary, Pleistocene",Fluvioglacial ice-contact deposits mainly in kames and small eskers. Includes some small outwash and ground-moraine deposits. Typically silt-laden pebble and some cobble gravel; locally short beds of sand and silt,,,GU101,115,Gulkana,Unconsolidated,140,,,1400
Qog,Glacial deposits,Pleistocene,Glacial drift deposits older than Wisconsin glaciation; probably of Illinoian age,,,NB002,105,Nabesna,Unconsolidated,190,,,1900
Qog,Drift of older (Wisconsin and older?) glaciation,Pleistocene,"Chiefly ground moraine extensively modified by alluvial and colluvial processes. Diamiction; locally alluvial sand, gravel, and boulders.",,,VA007,18,Valdez,Unconsolidated,190,,,1900
Qig,Drift of intermediate glaciation,"Quaternary, Pleistocene",Drift deposits mostly on moderately steep slopes. Chiefly ground with some lateral moraines; a few ponds. Mostly diamicton and some gravel. Locally mixed with and overlain by colluvial and alluvial deposits,,,GU101,123,Gulkana,Unconsolidated,190,,,1900
Qigl,Drift of intermediate glaciation - lateral moraines,"Quaternary, Pleistocene","Lateral moraines, some of which have gently sloping ridge crests. Chiefly diamicton and rubble",,,GU101,124,Gulkana,Unconsolidated,190,,,1900
Qog,Drift of Older Glaciations,"Quaternary, Pleistocene","Undifferentiated glacial and fluvioglacial deposits interlayered with occasional thin volcanic flows. Observed only in north wall of Jacksina Glacier valley where unit is overlain by a dacitic andesite agglutinate flow (Qdaa) approximately 1.3 my old. Chiefly diamicton and sand, gravel, and boulders. Probably older than most of basaltic cinder cones (Qbc)",,,NB109,309,Nabesna,Unconsolidated,190,,,1900
Qog,Drift of older glaciation,"Quaternary, Pleistocene","Chiefly ground-moraine and fluvial (?) deposits on a few gently sloping plateaus and ridge crests about about 1500 m elevation on northern parts of Mt. Drum. Diamicton and accumulations of subrounded to rounded pebbles, cobbles and boulders. Pre-Wisconsin, in large part possibly Illinoian in age",,,GU101,125,Gulkana,Unconsolidated,200,,,2000
Tg,"Glacial, fluvioglacial, and boulder deposits",Tertiary,"Weakly consolidated, poorly sorted, fluvioglacial deposits, glacial volcanic boulder deposits, and localized tillite",Lignitized wood,,NB002,115,Nabesna,Sedimentary,220,,,2200
Qcg,Conglomerate,Pleistocene,"Weakly indurated pebble to boulder conglomerate and interbedded lenses of sandstone. Conglomerate is continuation of more extensive sedimentary rock unit mapped in the contiguous Gulkana A-1 quadrangle (Richter and others, 1994).",,,VA007,6,Valdez,Sedimentary,455,,,4550
Qw,Wrangell Lava (younger part),Quaternary,"Andesite and dacite flows, dacite domes, and interbedded breccias and pyroclastic rocks (near Mount Shields stratovolcanoes). basalt, andesite, and dacite flows and basaltic lapilli tuff (near Icefields Plateau area), dacite flow (near Drop Glacier and Copper River). Basalt and andesite flows (near West Glacier)",,,NB002,111,Nabesna,Igneous,455,,,4550
Qcc,Volcanic rocks-Capital Volcano,Pleistocene,Caldera lavas,,,GU002,130,Gulkana,Igneous,301,,,3015
Qcs,Volcanic rocks-Capital Volcano,Pleistocene,Shield lavas,,,GU002,131,Gulkana,Igneous,301,,,3015
Qdf,Volcanic rocks-Drum Volcano,Pleistocene,Cone building flows,,,GU002,118,Gulkana,Igneous,301,,,3013
Qsf,Volcanic rocks-Sanford Volcano,Pleistocene,"Basalt, andesite, and dacite lava, undifferentiated",,,GU002,123,Gulkana,Igneous,301,,,3014
Qwf,Volcanic rocks-Wrangell Volcano,Holocene (?) and Pleistocene,Andesite flows and fragmental rocks,,,GU002,115,Gulkana,Igneous,455,,,4550
Qwc,Wrangell Volcano -- East Crater deposits,Holocene and Pleistocene,"Wrangell Volcano -- East Crater deposits. Altered flows, breccias, and tuffs.",,,NB008,808,Nabesna,Igneous,301,,,3011
Qwa,Wrangell Volcano -- Two-pyroxene high-silica andesite flows,Pleistocene,"Wrangell Volcano, two-pyroxene high-silica andesite flows.Medium- to dark-gray, thin to thick (5-30 m) lava flows that generally exhibit oxidized and slightly scoriaceous tops and bottoms.",,,NB008,809,Nabesna,Igneous,301,,,3011
Qwbf,Wrangell Volcano -- Olivine basalt flow and breccia,Pleistocene,"Wrangell Volcano, olivine basalt flow and breccia.",,,NB008,810,Nabesna,Igneous,301,,,3011
Qwbc,Wrangell Volcano -- Cinder cone,Pleistocene,"Wrangell Volcano, cinder cone. All rocks probably of basalt or basaltic andesite composition.",,,NB008,811,Nabesna,Igneous,301,,,3011
Qsd,Mount Sanford volcano -- Low-silica dacite flows,Pleistocene,"Mount Sanford volcano, low-silica dacite flows",,,NB008,813,Nabesna,Igneous,301,,,3014
Qsy,"Mount Sanford volcano -- Young basaltic andesite, andesite, and dacite lavas, undifferentiated",Pleistocene,"Mount Sanford volcano, young basaltic andesite, andesite, and dacite lavas, undifferentiated",,,NB008,814,Nabesna,Igneous,301,,,3014
Qso,Mount Sanford volcano -- Older volcanic rocks,Pleistocene,"Mount Sanford volcano, older volcanic rocks. Chiefly interlayered thick lava flows, flow breccias, and debris and mudflow deposits that are mostly of andesitic or basaltic andesitic composition.",,,NB008,816,Nabesna,Igneous,301,,,3014
Qbf,Flows,Pleistocene,"Flows are equivalent to the olivine andesite flows (unit Qf) mapped in the contiguous Nabesna B-6 quadrangle (Richter and others, 1993).",,,NB008,832,Nabesna,Igneous,301,,,3010
Qaa,Andesite agglutinate,Pleistocene,"Andesite agglutinate, local source probably derived from the collapse of a large cinder/spatter cone in the area now covered by a younger dacitic center in the adjacent Nabesna A-5 quadrangle.",,,NB008,835,Nabesna,Igneous,355,,,3551
Qdv,Andesite flows,Pleistocene,"Mt. Drum volcano. Medium to dark gray, porphyritic olivine-bearing andesite lava flows containing phenocrysts of plagioclase, olivine, and orthopyroxene in a cryptocrystalline groundmass.",,,VA007,3,Valdez,Igneous,301,,,3013
Qwc,Mt. Wrangell west summit crater,Holocene,"Altered flows, breccias, and tuffs.",,,VA007,30,Valdez,Igneous,301,,ALT,3011
Qw,Mt. Wrangell shield lava,Quaternary,"Mt. Wrangell shield lava. Medium to dark gray, moderately to highly porphyritic two-pyroxene high-silica andesite flows.",,Whole rock K/Ar ages range from 282 ka to 516 ka,VA007,13,Valdez,Igneous,301,,,3011
Qwv,Mt. Wrangell valley-fill and basin lavas,Quaternary,"Moderately to highly porphyritic, two-pyroxene high-silica andesite flows mineralogically and chemically identical to Mt. Wrangell shield lavas.",,Whole rock K/Ar ages range from 25 ka to 270 ka,VA007,17,Valdez,Igneous,301,,,3012
Qwu,"Mt. Wrangell shield and valley fill lavas, undifferentiated",Quaternary,"Mt. Wrangell shield and valley fill lavas, undifferentiated. Restricted to exposures in nunataks that were not visited on the upper slopes of Mt. Wrangell.",,,VA007,16,Valdez,Igneous,301,,,3011
Qah,Andesite flows,Pleistocene,"Medium gray, slightly to moderately porphyritic andesite flows containing phenocrysts of plagioclase, orthopyroxene, hornblende, and traces of clinopyroxene and olivine in a cryptocrystalline to plagioclase rich groundmass.",,,VA007,25,Valdez,Igneous,455,,,4550
Qba,Basaltic andesite flows,Pleistocene,"Dark gray, slightly porphyritic basaltic andesite flows containing phenocrysts of olivine, and a trace of clinopyroxene in a groundmass consisting of plagioclase laths.",,,VA007,7,Valdez,Igneous,455,,,4550
Qcl,"Lava flows, pyroclastic deposits, and breccias, undifferentiated",Pleistocene,"Lava flows, pyroclastic deposits, and breccias, undifferentiated. Chiefly a variety of dark brownish gray andesite lava flows.",,Whole rock K/Ar ages of 1580 ka and 980 ka from andesitic lava flows,VA007,9,Valdez,Igneous,455,,,4550
Qwlf,Flow and pyroclastic rocks from Mt. Wrangell - Dacite / andesite flows,"Quaternary, Pleistocene","Flows of dacite and andesite (?). Rock is medium gray, locally vesicular, and contains phenocrysts",,,GU101,141,Gulkana,Igneous,301,,,3011
Qsl,Lava flows from Mt. Sanford,"Quaternary, Pleistocene",Lava flows exposed beneath glacial deposits,,,GU101,144,Gulkana,Igneous,301,,,3014
Qbf,Wrangell Lava - Basalt and basaltic andesite flows,"Quaternary, Pleistocene",Dense flows with localized columnar jointing. Gray olivine basalt. Originated from vents in s.e. corner of map area.,,K-Ar date of equivalent rocks in A-5 is 0.89 +/- 0.21 m.y.,NB108,517,Nabesna,Igneous,301,,,3010
Qabf,Wrangell Lava - Andesite and basaltic andesite flows,"Quaternary, Pleistocene","Thin to medium flows with oxidized dark-red scoraceous tops and bottoms. Gray in color, with sparse olivine, hypersthene, and plagioclase phenocrysts. Apparently related to an extensive sequence of flows in Nabesna A-5 quadrangle, where presumed local sources are presently ice-covered",,,NB108,519,Nabesna,Igneous,301,,,3010
Qwws,Wrangell volcano - Shield lavas ,"Quaternary, Holocene and Pleistocene",Chiefly andesite,,,GU003,334,Gulkana,Igneous,301,,,3011
Qdad,Wrangell Lava - Dacite and Andesite Domes and Flows,"Quaternary, Pleistocene","Broad, irregular-topped piles of massive columnar-jointed lavas. Rocks are chiefly dark-gray to black andesites and dacites containing small phenocrysts. Source local, probably in part extruded beneath ice cover",,,NB109,314,Nabesna,Igneous,301,,,3010
Qgbf,Wrangell Lava - Mt. Gordon Basalt and Andesite Flows,"Quaternary, Pleistocene",Thin flows with oxidized dark-red scoriaceous tops and bottoms. Fresh rocks are dark gray and contain abundant phenocrysts,,,NB109,316,Nabesna,Igneous,301,,,3010
Qpaf,Wrangell Lava - Porphyritic Andesite and Dacitic Andesite Flows,"Quaternary, Pleistocene","Medium, dark-gray to black vesicular flows chiefly of two-pyroxene andesite. Rocks contain abundant, large conspicuous phenocrysts. Source unknown, probably local",,,NB109,317,Nabesna,Igneous,301,,,3010
Qbf,Wrangell Lava - Basalt and Basaltic Andesite Flows,"Quaternary, Pleistocene","Dense thin to thick extensive flows, locally exhibiting pronounced columnar jointing. Rocks are chiefly gray to dark-gray olivine basalts containing abundant phenocrysts. Indicated source areas are the Ice Fields Plateau, Jaeger Mesa, and an eruptive center in B-5",,K-Ar date on whole rock indicates age of 0.89 +/- 0.21 my,NB109,318,Nabesna,Igneous,301,,,3010
Qa,Wrangell Lava - Andesite Flows,"Quaternary, Pleistocene",A variety of medium to thick andesite flows apparently from a number of local but largely unknown source areas. Rocks range from light to dark gray and are not conspicuously porphyritic,,K-Ar date on plagioclase indicates age of 1.46 +/- 0.03 my,NB109,320,Nabesna,Igneous,301,,,3010
Qbt,Wrangell Lava - Basalt Tuff,"Quaternary, Pleistocene","Chiefly palogonitized air-fall lapilli tuff and ash and accretionary lapilli in beds and massive structureless tuff and block breccia. Rocks are semi-indurated and characteristically buff to yellow orange. Block, lapilli, and ash fragments consist wholly of glassy scoria containing phenocrysts. Apparently erupted from sub-ice vent(s) of the Ice Fields Plateau. Other basalt tuff deposits may not be contemporaneous",,,NB109,321,Nabesna,Igneous,301,,,3010
Qmbf,Wrangell Lava - Massive Basaltic Andesite Flow,"Quaternary, Pleistocene",Massive flow(s) of dense to vesicular basaltic andesite exhibiting pronounced columnar jointing. Rocks are dark gray to black and contain abundant phenocrysts. Unit caps north end of Lakes Plateau. Source is probably local,,,NB109,324,Nabesna,Igneous,301,,,3010
Qb,Wrangell Lava - Basalt,"Quaternary, Pleistocene","Short flows and small irregular masses intimately associated with, and probably the extrusive equivalent of the palagonitic basalt tuffs (Qbt) in the Ice Fields Plateau area. Rocks are dark gray to black and contain abundant olivine phenocrysts",,,NB109,325,Nabesna,Igneous,301,,,3010
Qabf,Wrangell Lava - Andesite and Basaltic Andesite Flows,"Quaternary, Pleistocene","Flows with dark-red scoriaceous tops and bottoms. Consists chiefly of gray to dark-gray flows containing sparse phenocrysts. Source is local, apparently under the present ice cover in the n.e. part of the Ice Fields Plateau",,,NB109,326,Nabesna,Igneous,301,,,3010
Qtbf,Wrangell Lava - Thin Basalt and Basaltic Andesite Flows,"Quaternary, Pleistocene","Three eruptive flow centers recognized. Similar to Mt. Gordon (Qgbf) and the young cinder cones (Qbc), but significantly older",,,NB109,327,Nabesna,Igneous,301,,,3010
Qws,Sanford volcano - Lava flows ,"Quaternary, Pleistocene",Chiefly andesite ,,,NB007,725,Nabesna,Igneous,301,,,3014
Qwc,Capitol volcano - Shield and intracaldera lavas ,"Quaternary, Pleistocene",Chiefly andesite,,,NB007,726,Nabesna,Igneous,301,,,3015
Qsp,Mount Sanford volcano -- Dacite pyroclastic flow,Pleistocene,"Mount Sanford volcano, dacite pyroclastic flow",,,NB008,815,Nabesna,Igneous,310,,,3100
Qdb,Dacite block and ash deposit,Pleistocene,"Contains blocks chiefly of light gray, porphyritic dacite as much as 2 m in diameter in a matrix of light gray to very light gray ash.",,,VA007,8,Valdez,Igneous,455,,,4550
Qpf,Pyroclastic flow,Pleistocene,"Pale yellowish brown to moderate yellowish brown pyroclastic flow containing abundant bombs, scoria, and pumice.",,Whole rock K/Ar age of 342 ka from a scoria bomb,VA007,27,Valdez,Igneous,314,,,3140
Qht,Ho-Hum dome complex -- Dacite tephra,Pleistocene,Ho-Hum dome complex. Dacite tephra,,,NB008,824,Nabesna,Igneous,311,,,3110
Qbt,Tuff,Pleistocene,"Chiefly palagonitized air-fall lapilli tuff, accretionaly lapilli, and ash.",,,NB008,834,Nabesna,Igneous,311,,,3110
Qwp,Flow and pyroclastic rocks from Mt. Wrangell - tuff and ash,"Quaternary, Pleistocene",Light-buff to light-gray deposits of tuff and probably ash flows,,,GU101,142,Gulkana,Igneous,311,,,3110
Qafp,Ash flow and pumice deposits from Mt. Wrangell or Mt. Drum,"Quaternary, Pleistocene","Semi-indurated rocks are light gray and consist of unsorted blocks, pumice, and ash of hornblende dacite generally overlying finer grained and stratified airfall beds of same composition. Upper 20 m. form bold light-gray cliffs with weakly developed columnar joints",,,GU101,143,Gulkana,Igneous,311,,,3110
Qbt,Wrangell Lava - Basalt tuff,"Quaternary, Pleistocene","Palagonitized air-fall lapilli tuff and ash, and accretionary lapilli in beds from 1 cm to 1 m in thickness. Rocks are semi-indurated and characteristically buff to yellow orange. Block, lapilli, and ash consist wholly of glassy scoria. Source is probably from sub-ice eruptive activity to the south.",,,NB108,518,Nabesna,Igneous,311,,,3110
Qsdf,Sanford debris flow deposits,Quaternary,Debris derived from collapse of a dome on Sanford Volcano. Flow traveled a great distance down the Sanford Glacier/River valley to confluence with the Copper River,,,GU002,180,Gulkana,Unconsolidated,312,,,3120
QTa,"Andesite mudflows, hyaloclastites, tephra, and flows",Pleistocene or Pliocene,"Andesite mudflows, hyaloclastites, tephra, and flows",,,NB008,838,Nabesna,Unconsolidated,312,,,3120
Qdc,Dacite debris apron,Pleistocene,Blocks and smaller fragments of hornblende dacite in crudely layered deposits.,,,VA007,14,Valdez,Igneous,465,,,4650
Qcf,Chetaslina volcanic debris flow,Pleistocene,"Multi-colored, voluminous debris avalanche deposit containing megablocks of both porphyritic and aphanitic andesite lava, hydrothermally altered lava, volcanic breccia, pyroclastic flow deposits, lacustrine sediments, and glacial deposits.",,,VA007,26,Valdez,Igneous,312,,,3120
Qvd,Volcaniclastic deposits - Volcanic debris flows,"Quaternary, Pleistocene",Includes the Chetaslina volcanic mass-flow deposit exposed along the Chetaslina and Copper Rivers and the Sanford volcanic debris flow exposed along the Sanford and Copper Rivers,,,GU003,332,Gulkana,Igneous,312,,,3120
Qvd,Volcanic debris flow,"Quaternary, Pleistocene",Includes the Chetaslina volcanic mass-flow deposit exposed along the Chetaslina and Copper Rivers and the Sanford volcanic debris flow exposed along the Sanford and Copper Rivers,,,GU003,337,Gulkana,Igneous,312,,,3120
Qda,Volcanic rocks-Drum Volcano,Pleistocene,Volcanic avalanche deposits,,,GU002,117,Gulkana,Unconsolidated,314,,,3140
Qda,"Nadina volcanic avalanche, landslide, and glacial deposits, undifferentiated",Pleistocene,"Mt. Drum volcano. Chiefly varigated, crudely stratified and poorly sorted juvenile bombs, pumice, and ash and blocks of andesite and dacite. Deposits are locally covered by, and mixed with, glacial drift.",,,VA007,12,Valdez,Igneous,314,,,3140
Qva,Volcanic avalanche deposits of Nadina Valley,"Quaternary, Pleistocene","Semiconsolidated and crudely stratified deposits of unsorted volcanic rock debris. Deposits range from light gray to buff to light shades of pinkish gray, green, and lavender and consist chiefly of fresh-appearing gray to buff blocks, pumice and ash of hornblende dacite or rhyodacite, and blocks",,,GU101,126,Gulkana,Igneous,314,,,3140
Qpf,Volcaniclastic deposits - Pyroclastic flows,"Quaternary, Pleistocene","Includes the extensive Nadina hot avalanche deposit from Mt. Drum and a pyroclastic flow (0.3 Ma), probably from Mt. Drum, at the junction of the two forks of the Chetaslina River",,,GU003,317,Gulkana,Igneous,314,,,3140
Qsh,Volcanic rocks-Sanford Volcano,Pleistocene,Hyaloclastite,,,GU002,122,Gulkana,Igneous,316,,,3160
QTvg,Wrangell Lava - Volcanic gravel,"Quaternary and Tertiary, Pleistocene, Pliocene, and Miocene","Unconsolidated to poorly consolidated. Totally unsorted diamicton, with boulders of lava and basement rocks as much as 1 m in diameter to well-bedded, locally sorted volcaniclastic debris that may have been fluvially reworked. Where semi-consolidated, locally eroded to form distinct pillars.",,,NB108,530,Nabesna,Igneous,317,,,3170
Qbc,Cinder cones and associated flows,Pleistocene,Cinder cones and associated flows,,,GU002,111,Gulkana,Igneous,320,,,3200
Qbc,Cinder cones,Pleistocene,Cinder cones,,,NB008,833,Nabesna,Igneous,320,,,3200
Qabv,Wrangell Lava - Andesite and basalt scoria,"Quaternary, Pleistocene","Red to black cinder cones, less than 500 m in diameter. Usually identifiable from air photographs",,,NB108,515,Nabesna,Igneous,320,,,3200
Qbc,"Cinder cones, flows, and tuffs ","Quaternary, Pleistocene",Chiefly olivine basalt and basaltic andesite,,,GU003,315,Gulkana,Igneous,320,,,3200
Qbc,Wrangell Lava - Basalt Cinder Cones,"Quaternary, Pleistocene","Basalt and basaltic andesite cinder cones. Chiefly scoria, blocks, spindle bombs, and lapilli intermixed with spatter debris, agglutinates, and minor thin flows. Many cones still retain original form",,,NB109,310,Nabesna,Igneous,320,,,3200
Qdac,Wrangell Lava - Dacite Cinder Cone,"Quaternary, Pleistocene",Chiefly dense glassy scoria. Rocks are dark gray and contain phenocrysts,,K-Ar on plagioclase indicates age of 1.34 +/- 0.20 my,NB109,312,Nabesna,Igneous,320,,,3200
Qrc,Wrangell Lava - Rhyolite Cinder Cone and Nuee Ardente Deposits,"Quaternary, Pleistocene","Cinder cone consists chiefly of unconsolidated rubble of dense glassy blocks, pumiceous scoria, and lapilli. Nuee andente deposits composed largely of bread-crust blocks in a matrix of unconsolidated ash and lapilli. Rocks are buff to light gray and contain rare small phenocrysts",,,NB109,319,Nabesna,Igneous,320,,,3200
Qbc,"Cinder cones, flows, and tuffs ","Quaternary, Pleistocene",Chiefly olivine basalt and basaltic andesite,,,NB007,720,Nabesna,Igneous,320,,,3200
Qzaf,Second-cycle cone-building flows - Two-pyroxene andesite,"Quaternary, Pleistocene","Two-pyroxene andesite and minor two-pyroxene dacite flows. Flows are from 1 to 20 m thick, with scoriaceous tops and bottoms, and are locally highly vesicular. Rocks are dark gray to meduim brownish gray. They contain small phenocrysts",,,GU101,131,Gulkana,Igneous,335,,,3350
Qzuf,Second-cycle cone-building flows - Undivided,"Quaternary, Pleistocene",Undivided andesite and dacite flows,,,GU101,134,Gulkana,Igneous,335,,,3350
Qafb,"Flows, flow breccias, and tuff","Quaternary, Pleistocene","Thin to thick flows, chiefly of andesite and dacite composition, interlayered with massive breccias, palagonitized airfall beds, and probably lahars. Deposits of buff-colored crystal-lithic tuff and breccia containing clasts of plagioclase and hornblende dacite porphyry in a tan trubid matrix. Flows are two-pyroxene andesites, olivine andesites, and two-pyroxene dacites. They are dark greenish gray, fine grained, and generally porphyritic, but locally equigranular and gabbroic in appearance. Porphyritic rocks contain small phenocrysts",,,GU101,140,Gulkana,Igneous,335,,,3350
Qa,Wrangell Lava - Andesite flows,"Quaternary, Pleistocene",Medium to thick augite-hypersthene-olivine-bearing andesite flows from local but unknown sources. Light to dark gray rock; not conspicuously porphyritic.,,K-Ar date of similar rocks indicates age of 1.46 +/- 0.03 m.y.,NB108,516,Nabesna,Igneous,335,,,3350
Qadf,Wrangell Lava - Andesite and dacite (?) flows,"Quaternary, Pleistocene","Thick, often glassy porphyritic flows with plagioclase the most common phenocryst. Flows exhibit small-scale but pronounced columnar jointing. Sources unknown, probably local",,,NB108,520,Nabesna,Igneous,335,,,3350
Qsdf,Dacite flows of Snider Peak,"Quaternary, Pleistocene",Massive dark-gray-weathering hornblende-rich flows that radiate from the general area of Snider Peak dome. Flows appear to consist of complex multiple-flow cooling units suggesting possibility of more than one source. They locally contain abumdant xenoliths and exhibit conspicuous columnar jointing. Rocks are light gray to pinkish meduim gray,,,GU101,128,Gulkana,Igneous,336,,,3360
Qzdf,Second-cycle cone-building flows - Thick lobate flows of dacite,"Quaternary, Pleistocene","Thick lobate flows of dacite and minor rhyodacite that form massive piles. Rocks are light to pinkish medium gray, weather dark reddish brown, and are porphyritic with phenocrysts",,,GU101,132,Gulkana,Igneous,336,,,3360
Qzof,Second-cycle cone-building flows - Olivine-bearing two-pyroxene dacite,"Quaternary, Pleistocene",Olivine-bearing two-pyroxene dacite and minor two-pyroxene andesite flows. Source unknown. Flows are thick and massive with locally pronounced columnar jointing. Rocks are medium to dark gray and contain small phenocrysts,,,GU101,133,Gulkana,Igneous,336,,,3360
Qdaa,Wrangell Lava - Dacite Andesite Agglutinate Flow,"Quaternary, Pleistocene","Extensive single flow with well-formed columnar joints and black glassy base. Rocks are gray to black and are mineralogically similar to unit Qdac, but contain abundant inclusions of both vitric and lithic volcanic debris.",,,NB109,311,Nabesna,Igneous,336,,,3360
Qdaf,Wrangell Lava - Dacite and Dacitic Andesite Flows,"Quaternary, Pleistocene","Massive, thick flows of dense black glassy lava",,,NB109,313,Nabesna,Igneous,336,,,3360
Qd,Wrangell Lava - Dacite Flow,"Quaternary, Pleistocene","Massive single flow unit, with dark-gray glassy base, light-gray crystalline interior, and vapor-phase vesicular top. Rocks contain small phenocrysts",,,NB109,315,Nabesna,Igneous,336,,,3360
Qr,Wrangell Lava - Rhyodacite,"Quaternary, Pleistocene","Thick, massive flows and irregular domelike masses locally exhibiting highly contorted columnar jointing. Rocks are light gray to pinkish gray and contain altered hornblende",,,NB109,322,Nabesna,Igneous,336,,,3360
Qrb,Wrangell Lava - Rhyodacite Tuff Brecia,"Quaternary, Pleistocene","Massive, structureless palagonitized breccia containing blocks and smaller fragments of rhyodacite. Breccia probably represents an ice-flow contact deposit",,,NB109,323,Nabesna,Igneous,336,,,3360
Qrf,Rhyolite flow,"Quaternary, Pleistocene",Remnant of flow-banded massive and glassy rhyolite flow that apparently was extruded from rhyolite dome (Qrd). Rock is light gray with small phenocrysts,,,GU101,139,Gulkana,Igneous,337,,,3370
QTb,Basalt dikes and sills,Quaternary or Tertiary,"Basalt dikes and sills, possibly related to Wrangell Lavas",,,BG002,161,Bering Glacier,Igneous,350,,,3500
Qja,Jarvis volcanic complex -- Andesite flows,Pleistocene,Jarvis volcanic complex. Andesite flows; undifferentiated lava flows and minor lahars and flow breccias.,,,NB008,827,Nabesna,Igneous,355,,,3551
Qjb,Jarvis volcanic complex -- Basalt flows,Pleistocene,Jarvis volcanic complex. Basalt flows,,,NB008,828,Nabesna,Igneous,355,,,3551
Qwj,Jarvis volcanoes - Shield and intracaldera lavas ,"Quaternary, Pleistocene",Chiefly andesite,,,NB007,721,Nabesna,Igneous,355,,,3551
Qwr,Wrangell Lava (rhyolite cinder cone),Quaternary,Rhyolite cinder cone and associated nuee ardente deposits,,,NB002,112,Nabesna,Igneous,401,,,4012
Qdc,Volcanic rocks-Drum Volcano,Pleistocene,Collapsed dome,,,GU002,121,Gulkana,Igneous,401,,,4011
Qsi,Volcanic rocks-Sanford Volcano,Pleistocene,Shallow plutons,,,GU002,124,Gulkana,Igneous,401,,,4012
Qdd,Volcanic rocks-Drum Volcano,Pleistocene,Dacite domes,,,GU002,119,Gulkana,Igneous,401,,,4011
Qdr,Volcanic rocks-Drum Volcano,Pleistocene,Rhyolite domes,,,GU002,120,Gulkana,Igneous,401,,,4011
Qsr,Volcanic rocks-Sanford Volcano,Pleistocene,Rhyodacite dome and flow,,,GU002,125,Gulkana,Igneous,401,,,4012
Qsi,"Mount Sanford volcano -- Dikes, undifferentiated",Pleistocene,"Mount Sanford volcano, dikes, undifferentiated",,,NB008,812,Nabesna,Igneous,401,,,4012
Qh,Ho-Hum Creek dome complex,Pleistocene,"Ho-Hum dome complex. An andesite-dacite dome-flow center northeast of the north Jarvis eruptive center. Complex consists chiefly of an older, central dome and flows of hornblende dacite and younger flows of andesite and dacite that exhibit mixed magma characteristics.",,,NB008,817,Nabesna,Igneous,401,,,4013
Qha,Ho-Hum dome complex -- Quartz-bearing high silica andesite flow,Pleistocene,Ho-Hum dome complex. Quartz-bearing high silica andesite flow,,,NB008,818,Nabesna,Igneous,401,,,4013
Qhad,Ho-Hum dome complex -- High silica andesite and dacite flows,Pleistocene,Ho-Hum dome complex. High silica andesite and dacite flows,,,NB008,819,Nabesna,Igneous,401,,,4013
Qhdd,Ho-Hum dome complex -- Dacite dikes,Pleistocene,Ho-Hum dome complex. Chiefly northerly trending dikes apparently restricted to central part of dome complex.,,,NB008,820,Nabesna,Igneous,401,,,4013
Qhp,Ho-Hum dome complex -- Dacite central plug,Pleistocene,Ho-Hum dome complex. Dacite central plug,,,NB008,821,Nabesna,Igneous,401,,,4013
Qhdi,Ho-Hum dome complex -- Dacite shallow intrusion (?),Pleistocene,Ho-Hum dome complex. Dacite shallow intrusion (?),,,NB008,822,Nabesna,Igneous,401,,,4013
Qhd,Ho-Hum dome complex -- Dacite dome and flows,Pleistocene,Ho-Hum dome complex. Undifferentiated dome rock and flows in central part of complex.,,,NB008,823,Nabesna,Igneous,401,,,4013
Qjdf,Jarvis volcanic complex -- Dacite flows,Pleistocene,Jarvis volcanic complex. Dacite flows,,,NB008,825,Nabesna,Igneous,401,,,4013
Qjd,Jarvis volcanic complex -- Dikes and plugs,Pleistocene,"Jarvis volcanic complex. Dikes and plugs; dikes examined were dark gray, porphyritic, olivine-bearing two pyroxene andesites.",,,NB008,826,Nabesna,Igneous,401,,,4013
Qdi,Dacite plugs,Pleistocene,"Light gray, moderately porphyritic hornblende dacite containing phenocrysts of plagioclase, hornblende, and traces of orthopyroxene in a cryptocrystalline to microcrystalline groundmass.",,,VA007,5,Valdez,Igneous,465,,,4650
Qd,Dacite flow dome,Pleistocene,Light gray porphyritic hornblende dacite containing phenocrysts of plagioclase and hornblende that is locally rimmed with black oxides in a cryptocrystalline groundmass.,,,VA007,4,Valdez,Igneous,465,,,4650
Qod,Dacite intrusion,Pleistocene,"Light olive-gray to greenish-gray porphyritic, containing phenocrysts of plagioclase, hornblende, and biotite in a cryptocrystalline groundmass locally flooded by calcite. Description from principal exposure to the north in the Gulkana A-1 quadrangle where unit intrudes older andesite flows of the Chetaslina lavas (Richter and others, 1994). ",,K-Ar age of 1.35 Ma,VA007,10,Valdez,Igneous,465,,,4650
Qsrd,Rhyodacite dome of Snider Peak,"Quaternary, Pleistocene","Remnant core of rhyodacite dome representing one of the latest stages of eruptive activity of Mt. Drum volcano. Rocks are light gray to light buff gray, have a sugary texture, and are locally vesicular",,,GU101,127,Gulkana,Igneous,401,,,4011
Qldd,Late dacite domes and associated flows,"Quaternary, Pleistocene",Six distinctive hornblende-biotite dacite domes and associated short massive flows mark climax of second cycle of eruptive activity of Mt. Drum volcano. Dacites are light to medium gray and conspicuously porphyritic with abundant phenocrysts,,,GU101,129,Gulkana,Igneous,401,,,4011
Qedd,Early dacite domes and associated flows,"Quaternary, Pleistocene",Three hornblende-dacite domes. Rocks of domes 1 and 2 are light to dark gray and porphyritic with abundant phenocrysts. Dome-3 rocks are generally coarser grained with common to abundant biotite.,,,GU101,130,Gulkana,Igneous,401,,,4011
Qui,Undifferentiated plugs and small intrusive bodies - Dacite,"Quaternary, Pleistocene",Chiefly light to medium gray dacite rocks with phenocrysts. One intrusive rhyodacite is light gray and contains phenocrysts,,,GU101,135,Gulkana,Igneous,401,,,4010
Qdd,Dacite dikes,"Quaternary, Pleistocene",Generally associated with rhyolite and rhyodacite domes. All dikes sampled are medium to dark gray and sparsely porphyritic with small phenocrysts,,,GU101,136,Gulkana,Igneous,401,,,4010
Qrd,Rhyolite domes,"Quaternary, Pleistocene","Four conspicuously light-colored rhyolite domes that are deeply dissected by erosion and expose light-colored cores cut by numerous dark-colored dacite dikes. Rocks are light gray, pink, and buff, and weakly porphyritic with small phenocrysts",,,GU101,137,Gulkana,Igneous,401,,,4010
Qrdd,Rhyodacite dome,"Quaternary, Pleistocene",Dissected hornblende rhyodacite dome probably related in age to rhyolite domes (Qrd). Rock is light gray with small phenocrysts,,,GU101,138,Gulkana,Igneous,401,,,4010
Qwsr,Sanford volcano - Dome,"Quaternary, Pleistocene",Rhyolite dome and flow,,,GU003,338,Gulkana,Igneous,401,,,4012
Qjd,Wrangell Lava - Dacitic Andesite and Dacite Flows,"Quaternary, Pleistocene",Flows with minor interbedded tuffs and breccias representing the main cone-building stage of Jarvis volcanoes. Rocks are dark gray to pinkish gray. Cut by numerous dark-colored andesite dikes,,K-Ar date on plagioclase indicates age of 1.63 +/- 0.42 my,NB109,329,Nabesna,Igneous,401,,,4013
Qwsr,Sanford volcano - Dome,"Quaternary, Pleistocene",Rhyolite dome and flow,,,NB007,727,Nabesna,Igneous,401,,,4012
Qwjd,Jarvis volcanoes - Dome ,"Quaternary, Pleistocene",Chiefly dacite,,,NB007,729,Nabesna,Igneous,401,,,4013
Qcr,Volcanic rocks-Capital Volcano,Pleistocene,Rhyolite dikes and laccoliths,,,GU002,128,Gulkana,Igneous,402,,,4020
Qtp,Andesite plug,Pleistocene,"Medium gray, plagioclase-rich andesite porphyry containing phenocrysts of fresh, euhedral plagioclase, clinopyroxene, and orthopyroxene in a cryptocrystalline groundmass.",,Whole rock K/Ar age of 529 ka,VA007,36,Valdez,Igneous,301,,,3011
Qcd,Andesite-dacite domes (?) and breccias,Pleistocene,"Andesite-dacite domes (?) and breccias. Light gray domes ranging from andesite containing plagioclase, orthopyroxene, clinopyroxene, and olivine to porphyritic dacite containing phenocrysts of plagioclase, clinopyroxene, orthopyroxene, and hornblende in a cryptocrystalline groundmass.",,Whole rock K/Ar age of 874 ka,VA007,20,Valdez,Igneous,465,,,4650
Qcd,Volcanic rocks-Capital Volcano,Pleistocene,Radial dike swarm and plugs,,,GU002,129,Gulkana,Igneous,403,,,4030
Qci,Andesite dikes,Pleistocene,"Two dikes, of the five observed were accessible and sampled. Both are dark gray slightly porphyritic andesite.",,,VA007,37,Valdez,Igneous,455,,,4550
QTma,"Wrangell Lava - Massive andesite, dacitic andesite flows and agglutinates","Quaternary and Tertiary, Pleistocene, Pliocene, and Miocene",100 m thick flows with pronounced columnar jointing exposed in s.w. corner of map. This is the same unit that makes up all the high Tanada peaks in B-6. Flow rocks are gray. Agglutinates are green with clasts of gray glassy dacitic andesite. Rocks locally altered to chlorite and clay minerals. Source(s) unknown.,,,NB108,521,Nabesna,Igneous,451,,ALT,4511
QTwi,Older volcanic and sedimentary rocks - Icefield flows ,"Quaternary and Tertiary, Pleistocene, Pliocene, and Miocene",Massive flows of high silica andesite capping the Icefields Plateau,,,NB007,724,Nabesna,Igneous,452,,,4520
QTwt,Tanada volcano ,"Quaternary and Tertiary, Pleistocene and Pliocene","Shield and intracaldera lavas, chiefly andesite",,,NB007,728,Nabesna,Igneous,451,,,4510
QTw,Wrangell Lava,Quaternary and Tertiary?,"At least 2,000 m of flows, tephra, and minor sedimentary rocks in northeastern Valdez quadrangle. Consists of mainly pyroxene andesite but ranges from basalt to dacite.",,"Dates as old as 10 Ma in adjacent Nabesna quadrangle, thought to be largely Quaternary in Valdez quadrangle.",VA002,455,Valdez,Igneous,301,,,3012
QTw,Wrangell Lava,Quaternary and Tertiary,"Calc-alkaline volcanic province including flows, tephra, and sedimentary units. Derived from shield or composite stratovolcano flows, or their satellite centers. Flows mainly andesite, also range from basalt to rhyolite, and less abundant dacite. Local sedimentary units include tuff and tillite. Wrangell Lava includes Tertiary tillite and the Frederika Formation which is mainly composed diverse conglomerate and sandstone, with lesser siltstone, shale, impure limestone, and lignite. Coextensive with counterparts in Nabesna Quad. Correlatives in Talkeetna Mountains, Alaska Peninsula, and the Aleutian Islands.",Fossil leaves from Frederika Formation indicate a Miocene age,K-Ar dates of tillite of 2.7 and 10 m.y.,MC002,24,McCarthy,Igneous,455,,,4550
QTw,Wrangell Lava (older part),Quaternary and Tertiary,"Undivided andesite and basaltic andesite flows, dacite flows anddacite domes, tuffs and breccias, and dacitic andesite agglutinate flows.",,K-Ar dates suggest a minimum of 10 m.y.,NB002,113,Nabesna,Igneous,455,,,4550
Qnf,Volcanic rocks-Nathlie Mountain eruptive center,Pleistocene,"Flows, breccias, and sedimentary rocks",,,GU002,127,Gulkana,Igneous,455,,,4550
QTu,Volcanic rocks,Pleistocene and Pliocene (?),"Volcanic rocks, undifferentiated",,,GU002,110,Gulkana,Igneous,455,,,4550
QTtd,Lavas of Tumble Creek -- Dacite flows?,Pleistocene or Pliocene,Lavas of Tumble Creek. Dacite flows?,,,NB008,829,Nabesna,Igneous,455,,,4550
QTta,"Lavas of Tumble Creek -- Andesite and basaltic andesite flows, lahars, and hyaloclastites",Pleistocene or Pliocene,"Lavas of Tumble Creek. Andesite and basaltic andesite flows, lahars, and hyaloclastites",,,NB008,830,Nabesna,Igneous,455,,,4550
Qwe,Early Mt. Wrangell lavas,Quaternary,"Early Mt. Wrangell lavas. The flows north of the Chetaslina Glacier are porphyritic, olivine-bearing, two-pyroxene andesites exhibiting magma mixing features. The isolated flows are also olivine-bearing tow-pyroxene porphyritic to seriate andesites.",,K/Ar age of 690 ka,VA007,19,Valdez,Igneous,301,,,3011
QTaf,Wrangell Lava - Andesite and basaltic andesite flows,"Quaternary and Tertiary, Pleistocene, Pliocene, and Miocene","Extensive flows with oxidized scoriaceous tops and bottoms. May include younger thin basalt flows from local eruptive centers. Locally, rocks are altered to chlorite and clay minerals. Distiguishing characteristics to QTau include a predominance of olivine over hypersthene and by the absense of pyroclastic beds",,,NB108,525,Nabesna,Igneous,455,,ALT,4550
QTad,Wrangell Lava - Andesite and acitic andesite dome,"Quaternary and Tertiary, Pleistocene, Pliocene, and Miocene",Gray rocks with plagioclase phenocrysts in a fine grained glassy matrix. May be associated with younger rocks of QTau and/or QTaf,,,NB108,526,Nabesna,Igneous,455,,,4550
QTav,Wrangell Lava - Old andesite and basaltic (?) scoria,"Quaternary and Tertiary, Pleistocene, Pliocene, and Miocene",Zones of bright-red breccia and bomb fragments. No topographic expression of small cone,,,NB108,527,Nabesna,Igneous,455,,,4550
QTau,"Wrangell Lava - Andesite flows, flow breccias, and volcaniclastic rocks, undifferentiated","Quaternary and Tertiary, Pleistocene and Pliocene","Gray hypersthene andesite flows with red scoriaceous tops and bottoms. Holocrystalline rocks with labradorite phenocrysts in a trachytic groundmass of plagioclase, minor clinopyroxene, and traces of olivine. Collective package of flows (< 5m) may exceed 1000 m. Massive lenses of breccia.",,K-Ar age of 2.77 +/- 0.10 m.y. Similar rocks in C-5 yielded an age of 1.97 +/- 0.15 m.y.,NB108,528,Nabesna,Igneous,455,,,4550
QTdb,Wrangell Lava - Basalt and andesite dikes,"Quaternary and Tertiary, Pleistocene, Pliocene, and Miocene","Small, nearly vertical fine-grained nonporphyritic olivine basalt and hypersthene andesite dikes. Glassy with local columnar jointing. Dikes almost certainly represent more than one episode of intrusion, perhaps widely separate in time",,,NB108,529,Nabesna,Igneous,455,,,4550
Tb,Wrangell Lava - Basalt flows,"Tertiary, Miocene","Vesicular, f. - m.g., locally porphyritic flows. Rocks locally chloritized and altered to clay minerals",,K-Ar date yielded 13.9 +/- 0.8 m.y.,NB108,535,Nabesna,Igneous,455,,ALT,4550
QTw,Wrangell Lava,"Quaternary and Tertiary, Holocene, Pleistocene, Pliocene, and Miocene","Differentiated calc-alkaline lava flows of andesite, basaltic andesite, and olivine andesite with minor volcanic conglomerate locally near the base. The lavas are dark gray and weather medium brown to dark yellowish brown",,,MC100,108,McCarthy,Igneous,455,,,4550
Qbb,Wrangell Lava - Basalt and Basaltic Andesite Breccias,"Quaternary, Pleistocene",Oxidized basaltic breccias apparently from old cinder cones. Fresh rocks are dark gray to black and contain phenocrysts,,,NB109,328,Nabesna,Igneous,455,,,4550
QTab,Wrangell Lava - Andesite Breccia,"Quaternary and Tertiary, Pleistocene, Pliocene, and older?",Massive sequence of light-gray to drab-brown fine to coarse structureless breccia,,,NB109,332,Nabesna,Igneous,455,,,4550
QTbf,Wrangell Lava - Basalt and Basaltic Andesite Flows,"Quaternary and Tertiary, Pleistocene, Pliocene, and older?",Extensive flows with oxidized dark-red scoriaceous tops and bottoms. Rocks are gray and contain small phenocrysts. Locally matrix is altered to chlorite and clay minerals,,,NB109,333,Nabesna,Igneous,455,,ALT,4550
QTuf,"Wrangell Lava - Undifferentiated Flows, Tuffs, and Breccias","Quaternary and Tertiary, Pleistocene, Pliocene, and older?","Chiefly flows of andesite, basaltic andesite, and basalt interbedded with a variety of pyroclastic deposits, volcanic mud flow deposits, and probably some volcano-glacial deposits. Rocks are locally altered to chlorite and clay. Sources from a number of poorly defined and covered older eruptive centers. Abundant andesite dikes",,K-Ar from correlative volcanic strata in B-5 suggest an age apan of 1.0 to 2.5 my,NB109,335,Nabesna,Igneous,455,,ALT,4550
QTw,Older volcanic and sedimentary rocks - Lava flows,"Quaternary and Tertiary, Pleistocene, Pliocene, and Miocene",Chiefly andesite and dacite. Includes the sedimentary non-marine Frederika Formation that occurs locally at the base of the Wrangell volcanic field in the southern Wrangell Mountains,,,NB007,719,Nabesna,Igneous,455,,,4550
QTi,Intrusive rocks,Pleistocene and Pliocene (?),Intrusive rocks,,,VA002,460,Valdez,Igneous,460,,,4600
Qbp,Plug,Pleistocene,"Small plug of olivine-bearing, sparsely porphyritic basaltic andesite.",,,NB008,831,Nabesna,Igneous,463,,,4630
QTai,Andesite dikes,Pleistocene or Pliocene,Andesite dikes,,,NB008,837,Nabesna,Igneous,463,,,4630
QTwr,Wrangell Lava (rhyodacite and rhyolite),Quaternary and Tertiary,"Rhyodacite and rhyolite domes, associated, nuee ardente and air-fall deposits (both locallized), local mudflow and tillite (?) deposits, and pumice lapilli tuff",,,NB002,114,Nabesna,Igneous,465,,,4650
Qni,Volcanic rocks-Nathlie Mountain eruptive center,Pleistocene,Dacite pluton,,,GU002,126,Gulkana,Igneous,465,,,4650
QTi,Intrusive rocks,Pleistocene and Pliocene (?),Intrusive rocks,,,GU002,113,Gulkana,Igneous,465,,,4650
Qwd,Volcanic rocks-Wrangell Volcano,Holocene (?) and Pleistocene,Dacite flows,,,GU002,116,Gulkana,Igneous,465,,,4650
QTrd,Rhyolite dome,Pleistocene or Pliocene,Rhyolite dome exposed chiefly in adjacent Nabesna A-5 quadrangle.,,,NB008,836,Nabesna,Igneous,465,,,4650
QTda,Undifferentiated intrusive dacite and associated breccias,"Quaternary and Tertiary, Pleistocene, Pliocene, and Miocene","Intrusive bodies consist of light- to medium-gray porphyritic dacite containing phenocrysts. Associated breccias are massive, brownish-gray, reddish-brown, and mauve rocks containing angular clasts of porphyritic dacite",,,GU101,145,Gulkana,Igneous,465,,,4650
QTrv,Wrangell Lava - Rhyodacite breccia,"Quaternary and Tertiary, Pleistocene, Pliocene, and Miocene","Strongly brecciated zones, probably representing vent areas, less than 100 m in diameter. Consists of rocks probably related to QTr. Minor dacite to rhyolitic rocks. Locally contains small glassy plugs and scoria. No topographic expression of cone",,,NB108,522,Nabesna,Igneous,465,,,4650
QTr,Wrangell Lava - Rhyodacite domes and associated flows,"Quaternary and Tertiary, Pleistocene and Pliocene","Massive gray rocks that weather pink-gray tan. Commonly porphyritic with abundant phenocrysts of plagioclase (60%), hypersthene, and minor oxyhornblende and altered biotite. Locally devitrified and altered to chlorite and clay minerals.",,Plagioclase K-Ar date is 3.74 m.y.,NB108,523,Nabesna,Igneous,465,,ALT-BIO,4650
QTdr,Wrangell Lava - Rhyodacite dikes,"Quaternary and Tertiary, Pleistocene, Pliocene, and Miocene","Medium-grained, locally pophyritic rocks with phenocrysts. Dikes range from 1 to 29 m in width and often occur in subparallel sets. Apparently associated with rhyodacite domes (QTr). Host andesites (QTau) locally contain sufides, chiefly pyrite, near contact",,,NB108,524,Nabesna,Igneous,465,,,4650
QTru,"Wrangell Lava - Rhyolite breccia and flows, undifferentiated","Quaternary and Tertiary, Pleistocene, Pliocene, and Miocene",Presumably formed from debris shed from domes (QTrd). Occur in poorly exposed dome margins,,,NB108,531,Nabesna,Igneous,465,,,4650
QTrt,Wrangell Lava - Rhyolite and rhyodacite pyroclastic deposits,"Quaternary and Tertiary, Pleistocene, Pliocene, and Miocene","Buff to light gray air-fall and nuee ardente deposits, locally reworked by water. Presumably associated with rhyolite domes (QTrd).",,,NB108,532,Nabesna,Igneous,465,,,4650
QTrf,Wrangell Lava - Rhyolite flow,"Quaternary and Tertiary, Pleistocene, Pliocene, and Miocene","Massive, light-gray, devitrified, microcrystalline rocks with red and black vitrophyre phases exhibiting pronounced flow banding. Presumably from rhyolite domes (QTrd)",,,NB108,533,Nabesna,Igneous,465,,,4650
QTrd,Wrangell Lava - Rhyolite domes,"Quaternary and Tertiary, Pleistocene, Pliocene, and Miocene","Light gray to buff, massive rocks with small phenocrysts of potassium feldspar, oxyhornblende, and altered biotite in a cryptocrystalline groundmass",,,NB108,534,Nabesna,Igneous,465,,ALT-BIO,4650
QTwr,Older volcanic and sedimentary rocks - Domes and intrusive rocks ,Quaternary (Pleistocene) and Tertiary (Pliocene and Miocene),Chiefly dacite and rhyolite,,,GU003,335,Gulkana,Igneous,465,,,4650
QTrd,Wrangell Lava - Rhyolite Dome,"Quaternary and Tertiary, Pleistocene, Pliocene, and older?",Light-colored dome with rubble carapace. Rocks are light gray to buff and fine-grained containing sparse altered hornblende,,,NB109,330,Nabesna,Igneous,465,,,4650
QTr,Wrangell Lava - Rhyodacite Dome,"Quaternary and Tertiary, Pleistocene, Pliocene, and older?","Gray, rubble-covered dome. Relation to other volcanic units is not certain. Rocks are light gray to gray and contain small altered hornblende",,,NB109,331,Nabesna,Igneous,465,,,4650
QTrf,Wrangell Lava - Rhyolite Flows and Domes,"Quaternary and Tertiary, Pleistocene, Pliocene, and older?",Extensive flows and domes of gray to pinkish-gray devitrified rhyolite with black porphyritic glassy base. Devitrified rock contains sparse phenocrysts. Glassy base contains abundant plagioclase,,K-Ar date on plagioclase indicates age of 2.85 +/- 0.05 my,NB109,334,Nabesna,Igneous,465,,,4650
QTwr,Older volcanic and sedimentary rocks - Domes and intrusive rocks ,"Quaternary and Tertiary, Pleistocene, Pliocene, and Miocene",Chiefly dacite and rhyolite,,,NB007,723,Nabesna,Igneous,465,,,4650
Ts,Sedimentary rocks,Cenozoic,Sedimentary rocks,,,GU002,135,Gulkana,Sedimentary,500,,,
QTy,Yakataga Formation,Pleistocene to Miocene,"Interbedded gray to dark-gray and greenish-gray siltstone, mudstone, and sandstone predominate in lower third of formation. Till-like diamictite is interbedded with siltstone and sandstone in all but lowest part of formation and is the dominant rock type in upper part of formation, particularly on Middleton Island. Conglomerate is a minor lithology throughout the formation, and scattered clasts-presumably dropstones-are present in all lithologies. Consists of diverse marine and glaciomarine clastic rocks along the Gulf of Alaska margin more than (?) m thick onshore and is widely distributed on the adjacent continental shelf where it is as much as (?) m thick in exploratory wells (Plafker and Addicott, 1976; Plafker and others, 1975). ",Contains an abundant marine megafauna and microfauna,,BG002,131,Bering Glacier,Sedimentary,565,,,
QTy,Yakataga Formation,Pleistocene to Miocene,"Consists of diverse marine and glaciomarine clastic rocks. Interbedded gray to dark-gray and greenish-gray siltstone, mudstone, and sandstone predominate in lower third of formation. Till-like diamictite dominant rock type in upper part of formation.",,,CV003,215,Cordova,Sedimentary,565,,,
QTy,Yakataga Formation,"Pleistocene(?), Pliocene and Miocene","More than 4,000 m of gray to dark-gray siltstone and mudstone, interbedded with massive subquartzose sandstone, diamictite (conglomeratic sandy mudstone or tillite), and conglomerate. Sandstone less than 25 to 30 percent of surface sections. ",Contains a moderately abundant molluscan megafauna and foraminiferal microfauna. Also rare fossil leaves and vetebrates.,,MS002,27,Mount Saint Elias,Sedimentary,565,,,
QTy,Yakataga Formation,Pleistocene to Miocene,"Interbedded gray to dark-gray and greenish-gray siltstone, mudstone, and sandstone predominate in lower third of formation. Till-like diamictite is interbedded with siltstone and sandstone in all but lowest part of formation and is the dominant rock type in upper part of formation, particularly on Middleton Island. Conglomerate is a minor lithology throughout the formation, and scattered clasts-presumably dropstones-are present in all lithologies. Consists of diverse marine and glaciomarine clastic rocks along the Gulf of Alaska margin more than (?) m thick onshore and is widely distributed on the adjacent continental shelf where it is as much as (?) m thick in exploratory wells (Plafker and Addicott, 1976; Plafker and others, 1975). ",Contains an abundant marine megafauna and microfauna,,IB002,131,Icy Bay,Sedimentary,565,,,
Tk,Kulthieth formation,Eocene,"Unit consists of massive to thin-bedded coal-bearing, arkosic sandstone, dark-gray to black carbonaceous siltstone and shale, and minor coal. Sandstone and shale ratios in measured sections average about 1:1. The sandstone varies from massive intervals as much as 492 ft thick to thin bedded and shaly. Bituminous to semianthracite coal in beds as much as 10 ft thick is a conspicuous, but minor part of the sequence. Commonly intensely deformed into imbricated stacks of fault-bounded chevron folds with shearing and structural thinning and thickening of coal beds. Mostly nonmarine and has minor tongues of transitional marine strata lithologically similar to the underlying Stillwater Formation and overlying Tokun Formation. Kulthieth formation","plants, and mollusks ",,CV002,250,Cordova,Sedimentary,640,,,
Tr,Redwood Formation,Pliocene to Oligocene?,"Lower sandstone member: about two-thirds thick-bedded sandstone and one-third silty sandstone and siltstone. Upper member: about one-half siltstone, mudstone and claystone, the rest is conglomerate and sandstone.",,,CV003,230,Cordova,Sedimentary,675,,,
Tr,Redwood Formation,Oligocene (?) and Miocene,"Marine siltstone, sandstone, and conglomerate. The sandstone member consists of about two-thirds thick-bedded sandstone and one-third silty sandstone and siltstone. The characteristic conglomeratic beds show complete gradation from coarse, clast-supported conglomerate to matrix-supported conglomeratic mudstone and sandstone in which coarse clasts are suspended in the matrix. The siltstone, mudstone, and claystone are similar in appearance to parts of the underlying Poul Creek Formation, but they contain few or no concretions, no glauconitic or volcanic beds, and are sandier and more resistant to erosion","mollusks, and foraminifera",,CV002,230,Cordova,Sedimentary,675
Tr,Redwood Formation,Oligocene (?) and Miocene,"Marine siltstone, sandstone, and conglomerate. The sandstone member consists of about two-thirds thick-bedded sandstone and one-third silty sandstone and siltstone. The characteristic conglomeratic beds show complete gradation from coarse, clast-supported conglomerate to matrix-supported conglomeratic mudstone and sandstone in which coarse clasts are suspended in the matrix. The siltstone, mudstone, and claystone are similar in appearance to parts of the underlying Poul Creek Formation, but they contain few or no concretions, no glauconitic or volcanic beds, and are sandier and more resistant to erosion.","mollusks, and foraminifera",,BG003,230,Bering Glacier,Sedimentary,675
Tr,Redwood Formation,Oligocene (?) and Miocene,"Marine siltstone, sandstone, and conglomerate. The sandstone member consists of about two-thirds thick-bedded sandstone and one-third silty sandstone and siltstone. The characteristic conglomeratic beds show complete gradation from coarse, clast-supported conglomerate to matrix-supported conglomeratic mudstone and sandstone in which coarse clasts are suspended in the matrix. The siltstone, mudstone, and claystone are similar in appearance to parts of the underlying Poul Creek Formation, but they contain few or no concretions, no glauconitic or volcanic beds, and are sandier and more resistant to erosion.","mollusks, and foraminifera",,CV002,230,Cordova,Sedimentary,675
Tp,Poul Creek Formation,Miocene to Eocene,"Shale and minor sandstone that is, in part, glauconitic, rich in organic material, and intercalated with intrabasinal, water-laid alkalic basaltic tuff, breccia, and pillow lava.",,,BG002,133,Bering Glacier,Sedimentary,680
Tps,"Sedimentary rocks, undivided","Tertiary, Oligocene and early Eocene","Concretionary, pyritic, glauconitic, reddish weathering, dark-gray to greenish-gray siltstone, claystone, and sandstone; subordinate dark-brown, laminated shale that is rich in organic material, silty shale, and gray calcareous sandstone; locally includes thin interbeds of basaltic tuff. ",Contains an abundant marine megafauna and microfauna,,BG002,134,Bering Glacier,Sedimentary,680
Tps,"Poul Creek Formation: Sedimentary rocks, undivided","Miocene, Oligocene, and Eocene","Concretionary, pyritic, glauconitic, reddish-weathering, dark-gray to greenish-gray siltstone, claystone, and sandstone; shale that is rich in organic material; gray calcareous sandstone; local thin interbeds of basaltic tuff.",,,CV003,235,Cordova,Sedimentary,680
Tps,"Poul Creek Formation: Sedimentary rocks, undivided","Miocene, Oligocene, and Eocene","Concretionary pyritic, and glauconitic reddish-weathering, ark-gray to greenish-gray siltstone, claystone, and sandstone with subordinate dark-brown, laminated organic-rich shale, and gray calcareous sandstone; also includes thin interbeds of basaltic tuff locally. Occurrence of shales as much as 800 ft thick that have high organic-carbon contents (as much as 7.57 percent), extractable petroleum (0.8 gallons per ton), abundant glauconite, and common pyrite are suggestive of deposition in part under conditions of restricted bottom circulation. Intercalated basaltic fragmental rocks and less common pillow basalt (unit Tpv) indicate episodic submarine mafic volcanism in the basin.","mollusks, and foraminifera",,CV002,235,Cordova,Sedimentary,680
Tps,"Sedimentary rocks, undivided (Poul Creek Formation)","Miocene, Oligocene, and Eocene","Concretionary pyritic, and glauconitic reddish-weathering, ark-gray to greenish-gray siltstone, claystone, and sandstone with subordinate dark-brown, laminated organic-rich shale, and gray calcareous sandstone; also includes thin interbeds of basaltic tuff locally. Occurrence of shales as much as 800 ft thick that have high organic-carbon contents (as much as 7.57 percent), extractable petroleum (0.8 gallons per ton), abundant glauconite, and common pyrite are suggestive of deposition in part under conditions of restricted bottom circulation. Intercalated basaltic fragmental rocks and less common pillow basalt (unit Tpv) indicate episodic submarine mafic volcanism in the basin.","mollusks, and foraminifera",,BG003,235,Bering Glacier,Sedimentary,680
Tps,"Sedimentary rocks, undivided (Poul Creek Formation)","Miocene, Oligocene, and Eocene","Concretionary pyritic, and glauconitic reddish-weathering, ark-gray to greenish-gray siltstone, claystone, and sandstone with subordinate dark-brown, laminated organic-rich shale, and gray calcareous sandstone; also includes thin interbeds of basaltic tuff locally. Occurrence of shales as much as 800 ft thick that have high organic-carbon contents (as much as 7.57 percent), extractable petroleum (0.8 gallons per ton), abundant glauconite, and common pyrite are suggestive of deposition in part under conditions of restricted bottom circulation. Intercalated basaltic fragmental rocks and less common pillow basalt (unit Tpv) indicate episodic submarine mafic volcanism in the basin.","mollusks, and foraminifera",,CV002,235,Cordova,Sedimentary,680
Tp,Poul Creek Formation,Oligocene,"Single outcrop consisting of 10 m of intensely sheared, reddish-brown weathering, dark-greenish-black glauconitic and pebbly sandstone containing abundant mafic volcanic detritus. Thought to be correlative with Poul Creek Formation",,,MS002,33,Mount Saint Elias,Sedimentary,680
Tps,"Sedimentary rocks, undivided","Tertiary, Oligocene and early Eocene","Concretionary, pyritic, glauconitic, reddish weathering, dark-gray to greenish-gray siltstone, claystone, and sandstone; subordinate dark-brown, laminated shale that is rich in organic material, silty shale, and gray calcareous sandstone; locally includes thin interbeds of basaltic tuff. ",Contains an abundant marine megafauna and microfauna,,IB002,134,Icy Bay,Sedimentary,680
Tpv,"Volcanic rocks, undivided","Tertiary, Oligocene and early Eocene","Basaltic pyroclastic and flow rocks, including minor pillowed lava flows; locally interbedded with marine sedimentary rocks, including tuffaceous or glauconitic strata. Probably related genetically to mafic dikes, sills, and plugs unit (Tm). [Note similarity to Meshik Volcanics]",,,IB002,135,Icy Bay,Igneous,680
Tt,Tokun Formation,"Tertiary, Eocene","Consists predominantly of concretionary siltstone and lesser, variable amount of interbedded sandstone, chiefly in lower part of formation. Siltstone generally is medium to dark gray and nearly massive; locally, thin beds and lenses of lighter gray, brown-weathering calcareous siltstone and silty limestone are found within darker siltstone. Spheroidal calcareous concretions as much as 1 m in maximum dimension are distributed randomly or along bedding surfaces in the siltstone. Thin beds of glauconitic sandstone occur near top of formation. Interbedded sandstone generally is lighter gray than the siltstone, is micaceous, feldspathic, and brown weathering. Occurs only east of Steller Glacier.",Contains a very sparse marine megafauna,,BG002,138,Bering Glacier,Sedimentary,810
Tt,Tokun Formation,Eocene,"Consists predominantly of concretionary siltstone and lesser, variable amount of interbedded sandstone. Siltstone is medium to dark gray and nearly massive. Spheroidal calcareous concretions as much as 1 m in maximum dimension are distributed randomly or along bedding surfaces in the siltstone.",,,CV003,240,Cordova,Sedimentary,810
Tt,Tokun Formation,Oligocene and Eocene,"A transgressive marine sequence. Consists predominantly of concretionary siltstone with a lesser and variable amount of interbedded sandstone, chiefly in the lower part of the formation. The siltstone generally is medium to dark gray and nearly massive; in places, thin beds and lenses of lighter gray brown-weathering calcareous siltstone and silty limestone occur within the darker siltstone. Interbedded sandstone in the Tokun, which generally is lighter gray than the siltstone, is micaceous, feldspathic, and brown-weathering.","crabs, and mollusks",,CV002,240,Cordova,Sedimentary,810
Tt,Tokun Formation,Oligocene and Eocene,"A transgressive marine sequence. Consists predominantly of concretionary siltstone with a lesser and variable amount of interbedded sandstone, chiefly in the lower part of the formation. The siltstone generally is medium to dark gray and nearly massive; in places, thin beds and lenses of lighter gray brown-weathering calcareous siltstone and silty limestone occur within the darker siltstone. Interbedded sandstone in the Tokun, which generally is lighter gray than the siltstone, is micaceous, feldspathic, and brown-weathering","crabs, and mollusks",,BG003,240,Bering Glacier,Sedimentary,810
Tt,Tokun Formation,Oligocene and Eocene,"A transgressive marine sequence. Consists predominantly of concretionary siltstone with a lesser and variable amount of interbedded sandstone, chiefly in the lower part of the formation. The siltstone generally is medium to dark gray and nearly massive; in places, thin beds and lenses of lighter gray brown-weathering calcareous siltstone and silty limestone occur within the darker siltstone. Interbedded sandstone in the Tokun, which generally is lighter gray than the siltstone, is micaceous, feldspathic, and brown-weathering","crabs, and mollusks",,CV002,240,Cordova,Sedimentary,810
Ts,Stillwater Formation,"Tertiary, Eocene","Primarily consists of dense hard dark-gray siltstone. Where siltstone is carbonaceous, it has a coal-like appearance; where it is calcareous, it may be variegated from reddish brown to pale green and usually contains foraminifers. Occurs in limited outcrop area east of Steller Glacier",foraminifers,,BG002,137,Bering Glacier,Sedimentary,820
Ts,Stillwater Formation,Eocene,"Dense hard dark-gray siltstone. Where siltstone is carbonaceous, it has a coalike appearance; where its calcareous, it may be variegated from reddish brown to pale green",foraminifers,,CV003,256,Cordova,Sedimentary,820
Ts,Stillwater Formation,Eocene,"The dominant lithology is dense hard dark-gray siltstone. Where the siltstone is carbonaceous, it has a coaly appearance; where it is calcareous, the siltstone may be variegated in shades of reddish brown to pale green and usually contains foraminifers. The upper part of the formation indicates regressive shallow marine deposition. In this area the Stillwater intertongues with, and grades upward into, the shallow marine and nonmarine Kulthieth Formation. The Stillwater Formation is complexly deformed and is characterized by tight folds and shearing in incompetent strata; hence, its thickness can be only estimated to be at least 4,918 ft. ","foraminifers, and mollusks",,CV002,255,Cordova,Sedimentary,820
Ts,Stillwater Formation,Eocene,"The dominant lithology is dense hard dark-gray siltstone. Where the siltstone is carbonaceous, it has a coaly appearance; where it is calcareous, the siltstone may be variegated in shades of reddish brown to pale green and usually contains foraminifers. The upper part of the formation indicates regressive shallow marine deposition. In this area the Stillwater intertongues with, and grades upward into, the shallow marine and nonmarine Kulthieth Formation. The Stillwater Formation is complexly deformed and is characterized by tight folds and shearing in incompetent strata; hence, its thickness can be only estimated to be at least 4,918 ft. ","foraminifers, and mollusks",,BG003,255,Bering Glacier,Sedimentary,820
Tk,Kulthieth Formation,"Tertiary, Eocene","lncludes at least 1,500 m of interbedded, massive to thin-bedded, coal-bearing arkosic sandstone, dark-gray to black carbonaceous siltstone and shale, and minor coal. Sandstone:shale ratios in measured sections (Martin, 1908) average about 1:1. Sandstone varies from massive intervals as much as 150 m thick to thin-bedded and shaly intervals. Sub-bituminous to semi-anthracite coal in beds as much as 3 m thick is a conspicuous, but minor part of sequence. Commonly intensely deformed into imbricated stacks of fault-bounded chevron folds displaying shearing and structural thinning and thickening of coal beds. ",Contains a sparse marine megafauna and locally abundant plant fossils,,BG002,136,Bering Glacier,Sedimentary,860
Tk,Kulthieth Formation,Eocene,"Includes at least 1,500 m of interbedded, massive to thin-bedded, coal-bearing arkosic sandstone, dark-gray to black carbonaceous siltstone and shale, and minor coal. Commonly intensely deformed into imbricated stacks of fault-bounded chevron folds.",,,CV003,250,Cordova,Sedimentary,860
Tk,Kulthieth Formation,Eocene,"Consists of massive to thin-bedded coal-bearing, arkosic sandstone, dark-gray to black carbonaceous siltstone and shale, and minor coal. Sandstone and shale ratios in measured sections average about 1:1. The sandstone varies from massive intervals as much as 492 ft thick to thin bedded and shaly. Bituminous to semianthracite coal in beds as much as 10 ft thick is a conspicuous, but minor part of the sequence. Commonly intensely deformed into imbricated stacks of fault-bounded chevron folds with shearing and structural thinning and thickening of coal beds. Mostly nonmarine and has minor tongues of transitional marine strata lithologically similar to the underlying Stillwater Formation and overlying Tokun Formation.","plants, and mollusks ",,CV002,250,Cordova,Sedimentary,860
Tk,Kulthieth Formation,Eocene,"Consists of massive to thin-bedded coal-bearing, arkosic sandstone, dark-gray to black carbonaceous siltstone and shale, and minor coal. Sandstone and shale ratios in measured sections average about 1:1. The sandstone varies from massive intervals as much as 492 ft thick to thin bedded and shaly. Bituminous to semianthracite coal in beds as much as 10 ft thick is a conspicuous, but minor part of the sequence. Commonly intensely deformed into imbricated stacks of fault-bounded chevron folds with shearing and structural thinning and thickening of coal beds. Mostly nonmarine and has minor tongues of transitional marine strata lithologically similar to the underlying Stillwater Formation and overlying Tokun Formation.","plants, and mollusks ",,BG003,250,Bering Glacier,Sedimentary,860
Tk,Kulthieth Formation,"Tertiary, Eocene and late Paleocene","At least 3,000 m of orange weathering light-gray feldspathic to lithofeldspathic sandstone and calcareous sandstone interbedded with dark-gray siltstone, pebble conglomerate, and many thin beds of coal. Commonly well-indurated with bituminous rank coal. Complexly deformed into tight fault-bounded chevron folds overturned to south with bedding plane thrusts tending to be localized in coal beds.",Contains a sparse warm water molluscan megafauna and locally abundant sub-tropical plant fossils,,MS002,35,Mount Saint Elias,Sedimentary,860
Tk?,Kulthieth Formation(?),"Tertiary, Eocene and late Paleocene","At least 3,000 m of orange weathering light-gray feldspathic to lithofeldspathic sandstone and calcareous sandstone interbedded with dark-gray siltstone, pebble conglomerate, and many thin beds of coal. Commonly well-indurated with bituminous rank coal. Complexly deformed into tight fault-bounded chevron folds overturned to south with bedding plane thrusts tending to be localized in coal beds. ",Contains a sparse marine megafauna and locally abundant plant fossils,,MS002,36,Mount Saint Elias,Sedimentary,860
Tk,Kulthieth Formation,"Tertiary, Eocene and late Paleocene","At least 3,000 m of orange weathering light-gray feldspathic to lithofeldspathic sandstone and calcareous sandstone interbedded with dark-gray siltstone, pebble conglomerate, and many thin beds of coal. Commonly well-indurated with bituminous rank coal. Complexly deformed into tight fault-bounded chevron folds overturned to south with bedding plane thrusts tending to be localized in coal beds. ",Contains a sparse warm water molluscan megafauna and locally abundant sub-tropical plant fossils,,YA002,35,Yakutat,Sedimentary,860
Ts,Siltstone of Oily Lake,Eocene,"Dark-gray, siliciceous, organic-rich siltstone. Exposed only near Oily Lake in the Samovar Hills",,,MS002,37,Mount Saint Elias,Sedimentary,875
Tos,"Orca Group -- sedimentary rocks, undivided",Paleocene and Eocene?,"Marine argillite, siltstone, sandstone, and conglomerate. Argillite and siltstone are more abundant than the coarser-grained rocks. Well-bedded, repetitive finer-grained and coarser-grained strata; primary sedimentary features are diagnostic of deposition by sediment-gravity flow. Finer-grained facies dominate west of Valdez Arm. Conglomerate clasts are of diverse extrabasinal lithologies.",,,VA002,950,Valdez,Sedimentary,950
Tos,"Orca Group -- Sedimentary rocks, undivided","Tertiary, Eocene and Paleocene","Very thick, complexly deformed, monotonous sequence of thin- to thick-bedded turbidites consisting of sandstone, siltstone, and mudstone; metamorphosed to zeolite or prehnite-pumpellyite facies. Sandstone is feldspathic to litho-feldspathic. Abundant primary sedimentary features indicate deposition from sediment gravity flows, chiefly turbidity currents, in a submarine-fan complex. ","In Prince William Sound area to the west, contains sparse planktonic foraminifers, fossil crabs, pelecypods, and gastropods",,BG002,139,Bering Glacier,Sedimentary,950
Tos,"Orca Group -- Sedimentary rocks, undivided",Eocene and Paleocene,"Very thick, complexly deformed monotonous sequence of thin- to thick-bedded turbidites consisting of sandstone, siltstone, and mudstone; metamorphosed to zeolite or prehnite-pumpellyite facies. Abundant sedimentary features indicate deposition from sediment gravity flows on submarine-fan complex. Lenticular matrix-supported conglomerate, and pebbly mudstone and sandstone are widespread.","planktonic foraminifers, fossil crabs, pelecypods and gastropods",,CV003,271,Cordova,Sedimentary,950
Tos,"Orca Group -- Sedimentary rocks, undivided",Eocene (?) and Paleocene,"A sequence of thin- to thick-bedded sandstone, siltstone, and mudstone. Abundant sedimentary structures, such as graded bedding, crossbedding, and ripple marks, along with flute, groove, and load casts, indicate deposition from turbidity currents. Sandstone is more abundant than finer-grained rocks. Limestone lenses or concretions are found locally, and these, along with the earlier mentioned conglomerates, are characteristic of sedimentary rocks belonging to the Orca Group. Thin-section petrography indicates that most of the sandstones are feldspathic to feldspatholithic.","Pollen: Alnus (Alder) Foraminifers: Globogerina sp., G. senni, Globogerina sp. (hispid), Globorotalia sp. Echinoids: Holaster sp. ?Hypsopygaster sp., Nucleopygus",,CV002,271,Cordova,Sedimentary,950,,
Tots,Orca Group -- Tuffaceous sedimentary rocks,Eocene (?) and Paleocene,"Tuffaceous sedimentary rocks, volcaniclastic sandstone, and minor chert. Locally, these rocks contain abundant radiolarians and diatoms of probable Tertiary age (table 2). South of the Martin fault, this unit also includes minor pillow basalt and abundant volcanic breccia. The rocks are altered to a bright orange-weathering gossan and are intruded by numerous porphyritic dikes for a distance of 10 mi along the south side of the Martin fault.","Diatoms: Arachinodiscus cf., A. ehrenbergii, Trinacria ef., T. pileclus Silicoflagellates: ?Corbisema geometrica, ?Corbisema hastata, ?Corbisema triacontha, Dictyocha aspera, Navoculopgis constricta",,CV002,272,Cordova,Sedimentary,950,,
Tos,"Orca Group -- Sedimentary rocks, undivided",Eocene (?) and Paleocene,"ORCA GROUP: A sequence of thin- to thick-bedded sandstone, siltstone, and mudstone. Abundant sedimentary structures, such as graded bedding, crossbedding, and ripple marks, along with flute, groove, and load casts, indicate deposition from turbidity currents. Sandstone is more abundant than finer-grained rocks. Limestone lenses or concretions are found locally, and these, along with the earlier mentioned conglomerates, are characteristic of sedimentary rocks belonging to the Orca Group. Thin-section petrography indicates that most of the sandstones are feldspathic to feldspatholithic.","Pollen: Alnus (Alder) Foraminifers: Globogerina sp., G. senni, Globogerina sp. (hispid), Globorotalia sp. Echinoids: Holaster sp. ?Hypsopygaster sp., Nucleopygus",,BG003,271,Bering Glacier,Sedimentary,950,,
Tots,Orca Group -- Tuffaceous sedimentary rocks,Eocene (?) and Paleocene,"ORCA GROUP: Tuffaceous sedimentary rocks, volcaniclastic sandstone, and minor chert. Locally, these rocks contain abundant radiolarians and diatoms of probable Tertiary age (table 2). South of the Martin fault, this unit also includes minor pillow basalt and abundant volcanic breccia. The rocks are altered to a bright orange-weathering gossan and are intruded by numerous porphyritic dikes for a distance of 10 mi along the south side of the Martin fault.","Diatoms: Arachinodiscus cf., A. ehrenbergii, Trinacria ef., T. pileclus Silicoflagellates: ?Corbisema geometrica, ?Corbisema hastata, ?Corbisema triacontha, Dictyocha aspera, Navoculopgis constricta",,BG003,272,Bering Glacier,Sedimentary,950,,
Tos,"Orca Group -- Sedimentary rocks, undivided",Eocene (?) and Paleocene,"ORCA GROUP: A sequence of thin- to thick-bedded sandstone, siltstone, and mudstone. Abundant sedimentary structures, such as graded bedding, crossbedding, and ripple marks, along with flute, groove, and load casts, indicate deposition from turbidity currents. Sandstone is more abundant than finer-grained rocks. Limestone lenses or concretions are found locally, and these, along with the earlier mentioned conglomerates, are characteristic of sedimentary rocks belonging to the Orca Group. Thin-section petrography indicates that most of the sandstones are feldspathic to feldspatholithic.","Pollen: Alnus (Alder) Foraminifers: Globogerina sp., G. senni, Globogerina sp. (hispid), Globorotalia sp. Echinoids: Holaster sp. ?Hypsopygaster sp., Nucleopygus",,CV002,271,Cordova,Sedimentary,950,,
Tots,Orca Group: --Tuffaceous sedimentary rocks,Eocene (?) and Paleocene,"ORCA GROUP: Tuffaceous sedimentary rocks, volcaniclastic sandstone, and minor chert. Locally, these rocks contain abundant radiolarians and diatoms of probable Tertiary age (table 2). South of the Martin fault, this unit also includes minor pillow basalt and abundant volcanic breccia. The rocks are altered to a bright orange-weathering gossan and are intruded by numerous porphyritic dikes for a distance of 10 mi along the south side of the Martin fault.","Diatoms: Arachinodiscus cf., A. ehrenbergii, Trinacria ef., T. pileclus Silicoflagellates: ?Corbisema geometrica, ?Corbisema hastata, ?Corbisema triacontha, Dictyocha aspera, Navoculopgis constricta",,CV002,272,Cordova,Sedimentary,950,,
Tos,"Orca Group -- Sedimentary rocks, undivided",Eocene (?) and Paleocene,"ORCA GROUP: A sequence of thin- to thick-bedded sandstone, siltstone, and mudstone. Abundant sedimentary structures, such as graded bedding, crossbedding, and ripple marks, along with flute, groove, and load casts, indicate deposition from turbidity currents. Sandstone is more abundant than finer-grained rocks. Limestone lenses or concretions are found locally, and these, along with the earlier mentioned conglomerates, are characteristic of sedimentary rocks belonging to the Orca Group. Thin-section petrography indicates that most of the sandstones are feldspathic to feldspatholithic.","Pollen: Alnus (Alder) Foraminifers: Globogerina sp., G. senni, Globogerina sp. (hispid), Globorotalia sp. Echinoids: Holaster sp. ?Hypsopygaster sp., Nucleopygus",,VA003,6271,Valdez,Sedimentary,950,,
Tovs,Orca Group -- Interbedded sedimentary and volcanic rocks,"Tertiary, Eocene and Paleocene","Variable proportions of interbedded, tholeiitic basalt (Tov) and turbidites (Tos).",,,BG002,141,Bering Glacier,Sedimentary,951,,
Tovs,Orca Group -- Interbedded sedimentary and volcanic rocks,Eocene and Paleocene,"Variable proportions of interbedded, tholeiitic basalt and turbidites. Basalt--pillowed and massive flows, pillow breccia, and tuff. Turbitdites--mudstone, siltstone, and fossiliferous volcanogenic sandstone. Metamorphosed to zeolite or prehnite-pumpellyite facies.",,,CV003,335,Cordova,Sedimentary,951,,
Tosv,Orca Group -- Interbedded sedimentary and mafic volcanic rocks,Eocene (?) and Paleocene,"Unit consists of locally variable amounts of volcanic and sedimentary rocks. In some cases unit is marginal to thicker sequences composed of pillowed and massive basalt flows. The lithologies are quite variable throughout the study area. In Ragged mountains volcaniclastic and tuffaceous sedimentary rocks are abundant, and pillow basalt is rare. These rocks are typically metamorphosed to zeolite or prehnite-pumpellyite facies and on Knight Island they have been converted to a hard hornfels by the abundant sills(?). Interbedded sedimentary and mafic volcanic rocks","Foraminifers: Globigerina or Subbotina; Globigerina sp. (?) Globorotalia sp.; Globigerina cf. G. senni, Globorotalia sp., ?Eoconuloides parvulus, Globigerina sp. (high spired), Globigerina sp. (hispid)",,CV002,332,Cordova,Sedimentary,951,,HFS
Tosv,Orca Group -- Interbedded sedimentary and mafic volcanic rocks,Eocene (?) and Paleocene,"ORCA GROUP: Unit consists of locally variable amounts of volcanic and sedimentary rocks. In some cases unit is marginal to thicker sequences composed of pillowed and massive basalt flows. The lithologies are quite variable throughout the study area. In Ragged mountains volcaniclastic and tuffaceous sedimentary rocks are abundant, and pillow basalt is rare. These rocks are typically metamorphosed to zeolite or prehnite-pumpellyite facies and on Knight Island they have been converted to a hard hornfels by the abundant sills(?). Interbedded sedimentary and mafic volcanic rocks","Foraminifers: Globigerina or Subbotina; Globigerina sp. (?) Globorotalia sp.; Globigerina cf. G. senni, Globorotalia sp., ?Eoconuloides parvulus, Globigerina sp. (high spired), Globigerina sp. (hispid)",,BG003,332,Bering Glacier,Sedimentary,951,,HFS
Tops,Orca Group -- Pillow basalt and sedimentary rocks,Eocene (?) and Paleocene,"ORCA GROUP: Pillow basalt, massive basalt flows, minor volcanic breccia interbedded with sandstone, siltstone, and shale. Distinguished from the interbedded sedimentary and mafic volcanics rocks unit on the basis of the predominance of pillow basalt in the section. Probably gradational with the pillow basalt unit. Two measured sections on Ellamar Mountain show significant differences in the percent of interbedded volcanic and sedimentary rocks that reflect rapid lensing out of units probably due to the presence of an irregular paleosurface. One section contains 92 percent volcanic rocks and 8 percent sedimentary rocks, and the other section about 1,200 ft laterally distant contains 75 percent volcanic rocks and 25 percent sedimentary rocks.",,,CV002,331,Cordova,Igneous,951,,
Tosv,Orca Group -- Interbedded sedimentary and mafic volcanic rocks,Eocene (?) and Paleocene,"ORCA GROUP: Unit consists of locally variable amounts of volcanic and sedimentary rocks. In some cases unit is marginal to thicker sequences composed of pillowed and massive basalt flows. The lithologies are quite variable throughout the study area. In Ragged mountains volcaniclastic and tuffaceous sedimentary rocks are abundant, and pillow basalt is rare. These rocks are typically metamorphosed to zeolite or prehnite-pumpellyite facies and on Knight Island they have been converted to a hard hornfels by the abundant sills(?). Interbedded sedimentary and mafic volcanic rocks","Foraminifers: Globigerina or Subbotina; Globigerina sp. (?) Globorotalia sp.; Globigerina cf. G. senni, Globorotalia sp., ?Eoconuloides parvulus, Globigerina sp. (high spired), Globigerina sp. (hispid)",,CV002,332,Cordova,Sedimentary,951,,HFS
Tos,"Orca Group, turbidites","Tertiary, early Eocene and late Paleocene","Mudstone to sandstone, locally fossiliferous submarine gravity flows",,,BG004,315,Bering Glacier,Sedimentary,951,,
Toc,Orca Group -- Conglomeratic sedimentary rocks,Paleocene and Eocene?,"Very poorly bedded conglomeratic sandstone and argillite mantle the tops of volcanic sequences. Conglomeratic rocks are very poorly sorted; clasts vary in size from granules to boulders and are supported by matrix. Basal parts of conglomeratic frequently contain angular to partly rounded clasts of basalt identical to substrate. Gradationally upward, the conglomeratic strata contain fewer volcanic clasts, but all other clasts are of lithologies that may be intrabasinal, in contrast to other conglomeratic beds in the Orca Group.",,,VA002,952,Valdez,Sedimentary,952,,
Toc,Orca Group: Conglomerate,Eocene and Paleocene,"Massive, clast-supported, well-rounded pebble, cobble, and boulder conglomerate. Variable clast composition.",,,CV003,270,Cordova,Sedimentary,952,,
Toc,Orca Group: Conglomerate,Eocene (?) and Paleocene,"Ranges from matrix-supported pebbly mudstone and sandstone to massive clast-supported pebble, cobble, and boulder conglomerate. The generally well-rounded clasts consist of various lithologies that have locally predominant types as follows: greenstone, sandstone, argillite, and limestone; felsic porphyry and tuff, granite, and sandstone; felsic tuff and porphyry; white quartz, felsic porphyry, and argillite; sandstone and siltstone. The conglomerates usually occur as lenses 300-700 ft thick within flyschoid rocks. The matrix-supported conglomerates and pebbly mudstones may have been formed by sub-marine landslides on unstable slopes.",Crab: Branchioplax washingtoniana Pelecypod: Acila decisa,,CV002,270,Cordova,Sedimentary,952
Toc,Orca Group: Conglomerate,Eocene (?) and Paleocene,"ORCA GROUP: Ranges from matrix-supported pebbly mudstone and sandstone to massive clast-supported pebble, cobble, and boulder conglomerate. The generally well-rounded clasts consist of various lithologies that have locally predominant types as follows: greenstone, sandstone, argillite, and limestone; felsic porphyry and tuff, granite, and sandstone; felsic tuff and porphyry; white quartz, felsic porphyry, and argillite; sandstone and siltstone. The conglomerates usually occur as lenses 300-700 ft thick within flyschoid rocks. The matrix-supported conglomerates and pebbly mudstones may have been formed by sub-marine landslides on unstable slopes.",Crab: Branchioplax washingtoniana Pelecypod: Acila decisa,,CV002,270,Cordova,Sedimentary,952
Toc,Orca Group: Conglomerate,Eocene (?) and Paleocene,"ORCA GROUP: Ranges from matrix-supported pebbly mudstone and sandstone to massive clast-supported pebble, cobble, and boulder conglomerate. The generally well-rounded clasts consist of various lithologies that have locally predominant types as follows: greenstone, sandstone, argillite, and limestone; felsic porphyry and tuff, granite, and sandstone; felsic tuff and porphyry; white quartz, felsic porphyry, and argillite; sandstone and siltstone. The conglomerates usually occur as lenses 300-700 ft thick within flyschoid rocks. The matrix-supported conglomerates and pebbly mudstones may have been formed by sub-marine landslides on unstable slopes.",Crab: Branchioplax washingtoniana Pelecypod: Acila decisa,,VA003,6270,Valdez,Sedimentary,952
Czab,Olivine basalt and andesite,Cenozoic,Olivine basalt and andesite,,,GU002,114,Gulkana,Igneous,1000
Ta,Andesite flows; Metamorphic Complex of Gulkana River,Tertiary (?),Andesite flows,,,GU002,158,Gulkana,Igneous,1000
Tif,Felsic to intermediate hypabyssal intrusive rocks,Tertiary,"Dikes, sills, and small stocks, compositionally diverse, dacite predominates but rocks range from rhyodacite to quartz latite and andesite.",,K-Ar age of 47 and 52 Ma reported as well as numerous 40 to 50 Ma ages and some as young as Pliocene.,VA002,1011,Valdez,Igneous,1011
Tsp,Andesite and basalt plugs(?),Tertiary,"Dark, generally aphanitic, dense andesite and basalt rock masses contained within breccias of unit Tsb. Wrangell lava; Sonya Creek Shield volcano; ring fracture(?) related rocks",,,MC003,313,McCarthy,Igneous,1040
Tsf,Andesite flows and tephra,Tertiary,"Dark, aphanitic lava flows and interlayered lapilli tuffs that overlie fragmental rocks of unit Tsb. May include some basalt flows. Wrangell lava; Sonya Creek Shield volcano; ring fracture(?) related rocks",,,MC003,315,McCarthy,Igneous,1040
Tsb,Andesite and basalt fragmental rocks,Tertiary,"Dark volcanic breccias and agglomerates, all generally welded and minor mudflows that are locally palagonitized. Breccias contain clasts as much as 5 m in diameter; agglomerates contain round and spindle bombs as much as 1 m long. Aphanitic to locally sparsely porphyritic. Unit appears to form the base of the sequence of lava flows and tephra in unit Tsf",,,MC003,314,McCarthy,Igneous,1040
Tcc,Andesite cinder cones,Tertiary,"Reddish, oxidized cinder and scoria. West of Sonya Creek, unit may include thin andesite flows. Wrangell lava; Sonya Creek Shield volcano; ring fracture(?) related rocks",,,MC003,300,McCarthy,Igneous,1040
Twl,Lavas of Wiki Peak,Tertiary,"Extensive, thin to locally thick (as much as 35 m), lava flows and subordinate interlayered lahars and lapilli tuffs that show an aggregate thickness of more than 1000 m. Basalt to dacite, but predominantly basaltic andesite and andesite. Wrangell lava; Sonya Creek Shield volcano; intracaldera(?) rocks",,"20.0 +/- 0.6 my, K/Ar, whole rock from a flow high in intracaldera section",MC003,219,McCarthy,Igneous,1040
Tbc,Basalt cinder cone and flow,Tertiary,"Red cinder cone and dark basalt flow. Flow contains aligned microphocrysts of plagioclase, clinopyroxene, and olivine. Wrangell lava; Sonya Creek Shield volcano; intracaldera(?) rocks",,,MC003,308,McCarthy,Igneous,1040
Tm,Mudflows(?),Tertiary,Structureless to locally stratified mudflows(?) containing clasts of angular volcanic rock as much as 10 m in diameter and minor rounded clasts of exotic plutonic rock. Unit appears to form basal unit in Sonya Creek caldera(?). Wrangell lava; Sonya Creek Shield volcano; intracaldera(?) rocks,,,MC003,305,McCarthy,Igneous,1040
Tvu,"Intracaldera(?) lavas, undifferentiated",Tertiary,"Mainly lava flows of intermediate composition; also includes interlayered mafic flows, pryoclastic deposits, lahars, and tuffs. Wrangell lava; Sonya Creek Shield volcano; intracaldera(?) rocks",,,MC003,,McCarthy,Igneous,1040
Tsl,Andesite flows,Tertiary,Aphanitic to porphyritic andesite and possibly dacite lava flows and minor interbedded mudflows and glassy agglomerates. Flows are mostly flat-lying and are generally less than 10 m thick; aggregate thickness about 350 m. Wrangell lava; Sonya Creek shield volcano; shield rocks,,,MC003,218,McCarthy,Igneous,1040
Tsm,Andesitic mudflows,Tertiary,"Thick (25 m), poorly sorted, and clast-supported mudflows and minor thin interbeds of mud-rich sand and gravel of andesite lava. Unit may include a few thin andesite lava flows. Aggregate thickness more than 230 m; base not exposed. Wrangell lava; Sonya Creek shield volcano; shield rocks",,,MC003,216,McCarthy,Igneous,1040
Tsu,"Shield lavas, undifferentiated",Tertiary,"Mapped only along the north margin of the inferred caldera. Chiefly south-dipping andesite lava flows, but includes a variety of flows and volcaniclastic rocks. Thickness probably more than 500 m. Wrangell lava; Sonya Creek shield volcano; shield rocks",,,MC003,301,McCarthy,Igneous,1040,,,
Tbpa,Prophyritic andesite flows,Tertiary,"Very extensive and thick two-pyroxene andesite lava flows that exhibit well-defined vertical columnar jointing. Coarsely porphyritic containing plagioclase, clinopyroxene, and orthopyroxene. Minor lithic clasts and association with andesitic agglutinates (Tba) suggest these lavas may have originated as agglutinates. Wrangell lava; Sonya Creek shield volcano; border volcanic and volcaniclastic rocks",,,MC003,211,McCarthy,Igneous,1040,,,
Tba,Andesite agglutinates,Tertiary,"Locally extensive 2-pyroxene andesite agglutinates as much as 30 m thick. Rock contains lithic clasts and, locally, streaks of glassy fiamme. Unlike the associated columnar-jointed flows (Tbpa), the agglutinates are only sparsely porphyritic. Wrangell lava; Sonya Creek shield volcano; border volcanic and volcaniclastic rocks",,,MC003,210,McCarthy,Igneous,1040,,,
Tbl,"Volcanic and volcaniclastic rocks, undifferentiated",Tertiary,"Sequence of interlayered flows and lahars, chiefly andesite composition, and, locally, volcanic gravel and conglomerate. Upper part overlies the dacite dome field and assoc. rocks (Tdh), but lower part appears to be intruded by dacite porphyry (Tdh), hence may include rocks of the older Rocker Creek lavas (Trl). Wrangell lava; Sonya Creek shield volcano; border volcanic and volcaniclastic rocks",,,MC003,212,McCarthy,Igneous,1040,,,
Tol,Andesite lavas and mudflows,Tertiary,"A sequence of tilted and interlayered porphyritic to aphanitic andesite lava flows and mudflows that dip 20-30 north. Aggregate thickness about 1000 m, but base is not exposed. Young Creek volcanic and volcaniclastic rocks",,"Two whole-rock K-Ar ages on single sample give ages of 18.6 and 19.1 Ma. Too young, probably reset; overlain by Sonya Ck. shield lavas (20 Ma) and intruded and tilted by subvolcanic rocks (Tdd, 23 Ma)",MC003,323,McCarthy,Igneous,1040,,,
Trl,"Rocker Creek volcanic and volcaniclastic rocks, undifferentiated",Tertiary,"Dark basalt to andesite lava flows and minor interlayered mudflows and maroon to dark-green volcanic siltstone, sandstone, and pebble conglomerate. Structurally deformed; bedding dips 20 to the southwest",,whole-rock K-Ar age of 26 Ma from basalt lava flow,MC003,319,McCarthy,Igneous,1040,,,
Tau,"Older andesites and basaltic andesites, undivided",Pliocene,"Older andesite and basaltic andesite, undivided",,,NB008,839,Nabesna,Igneous,455,,,4550
Trt,Rhyolite tephra,Tertiary,"Bedded, light-colored, rhyolitic air-fall deposits locally as much as 25 m thick. Exposed in the extreme northeast sector of caldera; may represent distal air-fall deposits of Twr. Wrangell lava; Sonya Creek Shield volcano; intracaldera(?) rocks",,,MC003,317,McCarthy,Igneous,1041,,,
Tpf,Dacite pyroclastic flow,Tertiary,"Light-colored, paleovalley-filling dacite ash-flow tuff containing phenocrysts of plagioclase, quartz, and minor hornblende and clinopyroxene in a welded pumiceous groundmass. Wrangell lava; Sonya Creek Shield volcano; intracaldera(?) rocks",,,MC003,303,McCarthy,Igneous,1041,,,
Tsa,Dacite agglutinate,Tertiary,"Extensive but relatively thin (25-35 m) dacite agglutinate consisting of densely welded flattened pumice, stretched glass fragments, and equidimensional lithic fragments exhibiting a well developed eutaxitic texture. Agglutinate appears to be a single flow interlayered in Tsl. Wrangell lava; Sonya Creek shield volcano; shield rocks",,,MC003,217,McCarthy,Igneous,1041,,,
Trp,Rhyolite volcaniclastic rocks,Tertiary,Light-colored pyroclastic flows and tephra. Pyroclasitc flows contain glassy and fine-grained breadcrust bombs in ash-rich matrix. Source is probably the rhyolite dome of unit Trr. Rocker Creek volcanic rocks,,,MC003,321,McCarthy,Igneous,1041,,,
Twr,Rhyolite flow(s),Tertiary,"Thick (200 m), light-colored and intricately flow-banded rhyolite lava containing abundant, pristine black obsidian. Locally includes as much as 2 m of overlying rhyolitic lapilli tuff and 10 m of rhyolitic volcanic sandstone. Wrangell lava; Sonya Creek Shield volcano; intracaldera(?) rocks",,,MC003,220,McCarthy,Igneous,1042,,,
Th,Hypabyssal rocks,Tertiary,"Dacite, andesite, and rhyodacite porphyry. Typically strongly porphyoritic. Correlates with younger porphyry of Nabesna quadrangle and with hypabyssal rocks associated with the Wrangell Lava in Alaska and Canada. Subdivision of unit Th of MacKevett (1978) south of range divide and Chitna River valley",,K-Ar on biotite of 3.8+0.8 m.y. and sanidine of 6.5+0.2 m.y.,MC006,432,McCarthy,Igneous,1234,,,
Tsd,Dacite dome,Tertiary,"Glassy, dense dacite dome exhibiting well-developed columnar joints. Wrangell lava; Sonya Creek Shield volcano; ring fracture(?) related rocks",,,MC003,316,McCarthy,Igneous,1043,,,
Tr,Rhyolite dome and plugs,Tertiary,"Light-colored, crystal-poor, flow-banded rhyolite. Rock contains a few percent of small plagioclase and biotite phenocrysts in a devitrified chalky matrix. The dome, exposed north of Ptarmigan Lake, apparently was endogenous, and it structurally deformed older sedimentary rocks (TKs) into which it was emplaced. Wrangell lava; Sonya Creek Shield volcano; ring fracture(?) related rocks",,,MC003,318,McCarthy,Igneous,1043,,,
Tdh,Dacite porphyry domes,Tertiary,Broad belt of at least eight coalesced endogenous and exogenous dacite domes that extends more that 19 km around and under the Sonya Creek shield volcano.,,"23 Ma, by K/Ar on hornblende from dome overlain by Sonya Creek intracaldera(?) rocks",MC003,215,McCarthy,Igneous,1043,,,
Tdr,Rhyolite domes,Tertiary,"Light-colored, fine-grained rhyolite containing sparse microphenocrysts of plagioclase, hornblende, biotite, and locally, rosettes of black tourmaline.",,,MC003,214,McCarthy,Igneous,1043,,
Trr,Rhyolite dome,Tertiary,Small light-colored dome or shallow intrusion that is locally highly brecciated. Rock is fine grained and chalky and contains occasional quartz eyes. Rocker Creek volcanic rocks,,,MC003,320,McCarthy,Igneous,1043,,
Th,Hypabyssal rocks,"Late Tertiary, Pliocene","Dikes, sills, and small stocks of silica-rich subvolcanic phases of parts of the Wrangell Lava. Comprise dacite and less abundant rhyodacite and andesite; rocks are very light gray to whitish and weather to buff, chalky white, or pale yellowish brown, generally altered, and locally cut by quartz-calcite veinlets. Dominantly porphyries, many have conchoidal fracture, and some dikes and sills are markedly platy",,K-Ar on hornblende from fresh dacite float from the Kuskulana Glacier moraine indicate an age of 3.8 +/- my,MC100,109,McCarthy,Igneous,1043,,ALT
Tm,Basaltic to andesitic plugs and dikes,"Tertiary, Miocene and Oligocene",Small basalt plugs and dikes. Generally amygdaloidal and vesicular; may exhibit flow structures. Generally too small to show on map. Some of the basaltic rocks may be of Oligocene age based on correlation with compositionally similar submarine flow and pyroclastic rocks interbedded with sedimentary rocks elsewhere along the Gulf of Alaska margin.,,,BG002,132,Bering Glacier,Igneous,1051,,
Tm,Basaltic to andesitic plugs and dikes,"Tertiary, Miocene and Oligocene(/)",Small basalt plugs and dikes. Generally amygdaloidal and vesicular; may exhibit flow structures. Generally too small to show on map. Some of the basaltic rocks may be of Oligocene age based on correlation with compositionally similar submarine flow and pyroclastic rocks interbedded with sedimentary rocks elsewhere along the Gulf of Alaska margin (Not shown on map),,,MS002,31,Mount Saint Elias,Igneous,1051,,
Td,Dacite of Cape Saint Elias,Pliocene or Miocene,Prominent very pale gray dacite plug complex that forms Cape Saint Elias and Pinnacle Rock at southwestern end of Kayak Island. Dacite is very dense and hard and is conspicuously jointed. Microgranitic and porphyritic texture.,,Whole-rock K-Ar age of 6.2 Ma,CV003,200,Cordova,Igneous,1053,,
Td,Rhyolite porphyry and granite,Pliocene(?) or Miocene(?),"Discordant hypabyssal plutons and related dikes at Mt. Owen and on east flank of Mt. Cook. Vary from porphyritic to fine-grained, hypidiomorphic and equigranular.",,,MS002,29,Mount Saint Elias,Igneous,1053,,
Tp,Younger porphyry,Tertiary,Porphyries ranging from andesite to rhyodacite. Dikes and sills with alteration. Porphyries may represent hypabyssal equivalent of the older part of the Wrangell Lava,,K-Ar data yields ages between 17 and 39 m.y.,NB002,126,Nabesna,Igneous,1055,,
Tp,Andesite plug,Tertiary,"Very dark andesite plug that may mark a principal eruptive area of the Sonya Creek volcano. Rock is aphanitic, containing sparse microphenocrysts of plagioclase, orthopyroxene, and clinopyroxene. Wrangell lava; Sonya Creek Shield volcano; intracaldera(?) rocks",,,MC003,309,McCarthy,Igneous,1055,,
Tp,Wrangell Lava - Hornblende porphyry,"Tertiary, Miocene","Small, complex, intrusive, dacite to andesite porphyries.",,K-Ar age from adjacent quad B-4 is 18.4 m.y.,NB108,536,Nabesna,Igneous,1055,,
Tp,Younger plutons - Wrangellia Terrane,Tertiary,Chiefly hornblende-feldspar and feldspar porphyry. Some of the younger plutons may be related to Wrangell volcanism,,K-Ar dates indicate ages of 17-39 Ma. ,NB007,718,Nabesna,Igneous,1055,,
Tpv,"Poul Creek Formation: Volcanic rocks, undivided",Miocene to Eocene,"Basaltic pyroclastic and flow rocks; locally interbedded with marine sedimentary rocks. Probably related genetically to mafic dikes, sills and plugs unit (Tm).",,,CV003,320,Cordova,Igneous,1080,,
Tpv,"Poul Creek Formation: Volcanic rocks, undivided","Miocene, Oligocene, and Eocene","Basaltic pyroclastic and flow rocks including minor pillowed flows; locally interbedded with marine sedimentary rocks, including tuffaceous or glauconitic strata, probably genetically related to mafic dikes, sills, and plugs of the mafic plugs unit (Tm).",,K/Ar date on whole rock of 31.2 + or - 1.3 Ma,CV002,320,Cordova,Igneous,1080,,
Tpv,"Poul Creek Formation -- Volcanic rocks, undivided","Miocene, Oligocene, and Eocene","Basaltic pyroclastic and flow rocks including minor pillowed flows; locally interbedded with marine sedimentary rocks, including tuffaceous or glauconitic strata, probably genetically related to mafic dikes, sills, and plugs of the mafic plugs unit (Tm)",,K/Ar date on whole rock of 31.2 + or - 1.3 Ma,CV002,320,Cordova,Igneous,1080,,
Tm,"Mafic dikes, sills, and plugs",Oligocene,"Mafic dikes, sills, and plugs. Strongly altered intrusions of diabase, alkalic basalt, olivine basalt, and lamprophyre. Probably related genetically to extrusive volcanic rocks (Tpv) in Poul Creek Fm.",,,CV003,423,Cordova,Igneous,1090,,
Tm,Mafic plugs,Oligocene (?),Only includes mafic plugs in the eastern Cordova quadrangle west of Nichawak Mountain; mainly in the Blying Sound quadrangle. Miller (1975) and Winkler and Plafker (1981) described the mafic plugs as coarse grained and diabasic with 45 percent euhedral plagioclase intergrown with 30 percent anhedral augite and enstatite. The remainder of the rock is composed of 5 percent opaque minerals and 20 percent secondary chlorite. ,,,CV002,423,Cordova,Igneous,1090,,
Tv,Basalt of Hubbs Creek,Eocene and Paleocene(?),"Mafic basalt, layered tuff, tuff breccia and breccia",,,MS002,96,Mount Saint Elias,Igneous,1125
Tov,"Orca Group -- volcanic rocks, undivided",Paleocene and Eocene?,"Tholeiitic pillow basalt, pillow breccia, and minor aquagene tuff. Thin sequences of dark-gray argillite and siltstone are interbedded with the volcanic rocks and locally compressed between pillows. Volcanic rocks are exclusively of oceanic tholeiite and are conformable with enclosing flyschoid sedimentary rocks.",,,VA002,1135,Valdez,Igneous,1135
Tov,"Orca Group -- Volcanic rocks, undivided","Tertiary, Eocene and Paleocene","Thick and thin tabular bodies of altered tholeiitic basalt consist chiefly of variably pillowed, massive, or crudely columnar flows, but also include pillow breccia, aquagene tuff, and diabase or gabbro sills. Minor mudstone and siltstone that are interbedded with basalt are included locally. Commonly contains green, gray, or red chert in interstices between pillows, rarely includes interpillow clots of pink limestone or black mudstone.",,,BG002,140,Bering Glacier,Igneous,1135
Tov,"Orca Group: Volcanic rocks, undivided",Eocene and Paleocene,"Thick and thin tabular bodies of altered tholeiitic basalt. Pillowed, massive or crudely columnar flows; pillow breccia, aquagene tuff, and diabase or gabbro sills. Local interbedding of mudstone and siltstone. Metamorphosed to zeolite or prehnite-pumpellyite facies.",,,CV003,333,Cordova,Igneous,1135
Tov,"Orca Group: Volcanic rocks, undivided",Eocene (?) and Paleocene,"Mostly tabular or lenticular bodies of mafic volcanic rocks altered to greenstone and not examined in detail. As mapped, may include pillowed or massive flows, broken pillow breccia, tuff, and dikes.",,,CV002,333,Cordova,Igneous,1135
Top,Orca Group: Pillow basalt,Eocene (?) and Paleocene,"ORCA GROUP: Pillow breccia and massive flows are subordinate in quantity to pillow basalt. Minor intercalated sedimentary rocks are predominantly siliceous mudstone and argillite. Interpillow material consists of silicious mudstone, sandstone, or carbonate rocks. Pillow basalts are porphyritic and have phenocrysts of plagioclase and clinopyroxene; olivine is present but not abundant. Altered brown-colored volcanic glass makes up much of the matrix especially in the outer parts of pillows. Vesticles are usually filled with calcite and (or) chlorite. This unit is gradational into sheeted dikes on Glacier and Knight Islands and into mixed sedimentary and volcanic rocks elsewhere.",,,CV002,330,Cordova,Igneous,1135
Tov,"Orca Group: Volcanic rocks, undivided",Eocene (?) and Paleocene,"ORCA GROUP: Mostly tabular or lenticular bodies of mafic volcanic rocks altered to greenstone and not examined in detail. As mapped, may include pillowed or massive flows, broken pillow breccia, tuff, and dikes.",,,CV002,333,Cordova,Igneous,1135
Tov,"Orca Group: Volcanic rocks, undivided",Eocene (?) and Paleocene,"ORCA GROUP: Mostly tabular or lenticular bodies of mafic volcanic rocks altered to greenstone and not examined in detail. As mapped, may include pillowed or massive flows, broken pillow breccia, tuff, and dikes.",,,VA003,6333,Valdez,Igneous,1135
Top,Orca Group: Pillow basalt,Eocene (?) and Paleocene,"Pillow breccia and massive flows are subordinate in quantity to pillow basalt. Minor intercalated sedimentary rocks are predominantly siliceous mudstone and argillite. Interpillow material consists of silicious mudstone, sandstone, or carbonate rocks. Pillow basalts are porphyritic and have phenocrysts of plagioclase and clinopyroxene; olivine is present but not abundant. Altered brown-colored volcanic glass makes up much of the matrix especially in the outer parts of pillows. Vesticles are usually filled with calcite and (or) chlorite. This unit is gradational into sheeted dikes on Glacier and Knight Islands and into mixed sedimentary and volcanic rocks elsewhere.",,,CV002,330,Cordova,Igneous,1136
Tops,Orca Group: Pillow basalt and sedimentary rocks,Eocene (?) and Paleocene,"Pillow basalt, massive basalt flows, minor volcanic breccia interbedded with sandstone, siltstone, and shale. Distinguished from the interbedded sedimentary and mafic volcanics rocks unit on the basis of the predominance of pillow basalt in the section. Probably gradational with the pillow basalt unit. Two measured sections on Ellamar Mountain show significant differences in the percent of interbedded volcanic and sedimentary rocks that reflect rapid lensing out of units probably due to the presence of an irregular paleosurface. One section contains 92 percent volcanic rocks and 8 percent sedimentary rocks, and the other section about 1,200 ft laterally distant contains 75 percent volcanic rocks and 25 percent sedimentary rocks.",,,CV002,331,Cordova,Igneous,1136
Tgb,Layered gabbro and cumulate ultramafic rocks in Fairweather Range,Tertiary,Layered gabbro and cumulate ultramafic rocks in Fairweather Range -- not on map,,,MS002,98,Mount Saint Elias,Igneous,1207
Tdqd,Quartz diorite,Tertiary,"Medium-grained, subhedral granular quartz diorite containing plagioclase, quartz orthoclase, chinopyroxene, and minor hornblende and biotite. Locally highly altered. Probably mostly subvolcanic and a variant of the diorite intrusive unit (Tdd)",,,MC003,213,McCarthy,Igneous,1055
Tdd,Diorite,Tertiary,"Medium-grained, subhedral granular diorite consisting of subhedral plagioclase, clinopyroxene generally altered to actinolite, and locally minor hornblende and biotite",,,MC003,322,McCarthy,Igneous,1055
Tp,Porphyry,Tertiary,Light-gray to gray hornblende-plagioclase dacite porphyry,,,NB109,336,Nabesna,Igneous,1234
Tg,Granodiorite,Tertiary,"Nonfoliate, fine- to medium-grained hypidiomorphic granular rocks of granodiorite, and subordinate granite, and local dioritic or gabbroic border zones",,K-Ar on biotite and hornblende of 8.4+0.25 m.y.,MC002,30,McCarthy,Igneous,1250
Ti,Intrusive rocks,Tertiary,"Elongate plutons, emplaced in Valdez Group, of medium-grained, hypidiomorphic-granular granodiorite and tonalite, late-stage dikes and sills of dacite. Assumed to be partial melt of flysch of Valdez Group. Similar rocks in Bering Quad. A dacite phase of inferred correlative in Anchorage Quad provided K-Ar",,K-Ar (from Anchorage quad) of 33.9+2 m.y.,MC002,26,McCarthy,Igneous,1273
Ti,Granodiorite,Miocene and Oligocene,"Dominantly fine- to medium-grained, equigranular to seriate hypidiomorphic muscovite-biotite and biotite granodiorite and related rocks in 10 small, widely distributed bodies cut diverse older plutonic and metamorphic rocks",,"K-Ar ages on mica yielded 20.9, 24.1, and 30.6 Ma; dates on possibly related dikes were 25.3 and 23.5 Ma.",MS002,19,Mount Saint Elias,Igneous,1273,,
Ti?,Granodiorite,Miocene and Oligocene,"Dominantly fine- to medium-grained, equigranular to seriate hypidiomorphic muscovite-biotite and biotite granodiorite and related rocks in 10 small, widely distributed bodies cut diverse older plutonic and metamorphic rocks",,"K-Ar ages on mica yielded 20.9, 24.1, and 30.6 Ma; dates on possibly related dikes were 25.3 and 23.5 Ma.",MS002,20,Mount Saint Elias,Igneous,1273,,
Tg,Granodiorite and granite,"Tertiary, Eocene","Chiefly light gray, fine- to coarse-grained, hypabyssal, muscovite-biotite granodiorite and granite that occur in four moderate-size stocks that chiefly intrude the Yakutat group",,K-Ar dates of 46.8 to 51.1 Ma,MS002,21,Mount Sanit Elias,Igneous,1300,,
Ti,Granodiorite,Miocene and Oligocene,"Dominantly fine- to medium-grained, equigranular to seriate hypidiomorphic muscovite-biotite and biotite granodiorite and related rocks in 10 small, widely distributed bodies cut diverse older plutonic and metamorphic rocks",,"K-Ar ages on mica yielded 20.9, 24.1, and 30.6 Ma; dates on possibly related dikes were 25.3 and 23.5 Ma.",YA002,19,Yakutat,Igneous,1273,,HFS
Ti3,Tonalite,Tertiary,"Mostly biotite tonalite but also includes biotite-muscovite +/- garnet tonalite and trondhjemite. Includes both weakly foliated, syn-D plutons (Ti3a) and unfoliated, post D plutons (Ti3b)",,,CV005,505,Cordova,Igneous,1273,,
Ti2,Tonalite ,Tertiary,Mostly hornblende-biotite tonalite but also includes biotite tonalite. Strongly foliated and lineated plutons with fabrics subparallel to D2 in adjacent metamorphic rocks,,,CV005,506,Cordova,Metamorphic,1273,,
Ti2,Tonalite ,Tertiary,Mostly hornblende-biotite tonalite but also includes biotite tonalite. Strongly foliated and lineated plutons with fabrics subparallel to D2 in adjacent metamorphic rocks,,,CV006,504,Cordova,Metamorphic,1273,,
Ti3b,Tonalite,Tertiary,"Mostly biotite tonalite, but also some biotite-muscovite +/- garnet trondhjemite and granodiorite. Unfoliated plutonic rocks",,,CV006,508,Cordova,Igneous,1273,,
Ti3a,Tonalite,Tertiary,"Mostly biotite tonalite, weakly foliated, syn-D plutons",,,CV006,512,Cordova,Metamorphic,1273,,
Tm,Mafic plugs,Oligocene (?),Only includes mafic plugs in the eastern Cordova quadrangle west of Nichawak Mountain mainly in the Blying Sound quadrangle. Miller (1975) and Winkler and Plafker (1981) described the mafic plugs as coarse grained and diabasic with 45 percent euhedral plagioclase intergrown with 30 percent anhedral augite and enstatite. The remainder of the rock is composed of 5 percent opaque minerals and 20 percent secondary chlorite. ,,,CV002,423,Cordova,Igneous,1285,,
Tgg,Granite and granodiorite,Eocene,Generally medium- and medium- to coarse-grained hypidiomorphic-granular biotite granite with border phases of biotite + or - hornblende granite to granodiorite and tonalite. Plutons of this unit are generally medium- and medium- to coarse-grained hypidiomorphic-granular biotite granite with border phases of biotite + or - hornblende granite to granodiorite and tonalite. The mafic mineral content varies with composition such that the color index of the granite ranges from 5 to 10; the granodiorite color index ranges from 10 to 20; and the tonalite color index ranges from 15 to 35.,,"Six K/Ar ages on hornblende, biotite, and phlogopite ranging from 50.5 to 53.5 Ma ",BG003,440,Bering Glacier,Igneous,1300,,
Tg,Granite and granodiorite,Tertiary? (Eocene?),"Two small discordant stocks of biotite-hornblende granite and granodiorite. Unfoliated, fine- to medium-grained hypiomorphic granular rocks. Equal proportions granite and granodiorite.",,,VA002,1305,Valdez,Igneous,1300,,
Tg,"Granite, granodiorite, and diorite -- Chugach terrane","Tertiary, Eocene","Chiefly light gray, fine- to medium-grained, hypabyssal, biotite and biotite-muscovite granite, granodiorite, and diorite that occur in small- to medium-size stocks that chiefly intrude the Valdez Group of the Chugach terrane",,,BG002,130,Bering Glacier,Igneous,1300,,
Tg,Tonalite and granodiorite -- Wrangellia and Alexander terranes,"Tertiary, Eocene","Small fine- to medium-grained, light-colored tonalite and granodiorite stocks, sills and dikes, only a few of which have been delineated on the map. The dikes consist manly of fine- to medium-grained biotite granite and lesser granodiorite and range in thickness from about 0.5 to 2 m. The dikes form conspicuous units that crosscut the intense structures and layering of the wall rocks.",,,BG002,130,Bering Glacier,Igneous,1300,,
Tg,Granitoid rocks,Eocene,"Granitoid rocks-- Biotite and biotite-hornblende granodiorite, granite, and minor tonalite; generally medium grained, hypidiomorphic, and equigranular; foliated in many places, especially near contacts with country rocks.",,K-Ar ages from 50.5 to 53.5 Ma,CV003,205,Cordova,Igneous,1300,,
Tgg,Granite and granodiorite,Eocene,Generally medium- and medium- to coarse-grained hypidiomorphic-granular biotite granite with border phases of biotite + or - hornblende granite to granodiorite and tonalite. Plutons of this unit are generally medium- and medium- to coarse-grained hypidiomorphic-granular biotite granite with border phases of biotite + or - hornblende granite to granodiorite and tonalite. The mafic mineral content varies with composition such that the color index of the granite ranges from 5 to 10; the granodiorite color index ranges from 10 to 20; and the tonalite color index ranges from 15 to 35.,,"Six K/Ar ages on hornblende, biotite, and phlogopite ranging from 50.5 to 53.5 Ma ",CV002,440,Cordova,Igneous,1300,,
Tg,Granodiorite and granite,"Tertiary, Eocene","Chiefly light gray, fine- to coarse-grained, hypabyssal, muscovite-biotite granodiorite and granite that occur in four moderate-size stocks that chiefly intrude the Yakutat Group",,K-Ar dates of 46.8 to 51.1 Ma,YA002,21,Yakutat,Igneous,1300
Tgt,Granite and tonalite (Granite),Eocene,"Consists of Alsek River pluton of strongly foliate, medium-grained, equigranular, hypidiomorphic muscovite-biotite granite and the Novatak Glacier pluton of foliate, fine- to medium-grained, equigranular to seriate, hypidiomorphic hornblende-biotite tonalite. (Separated for NSA)",,"Alsek River pluton has yielded a middle Tertiary K-Ar date, hornblende from the Novatak glacier pluton gave a 61 Ma K-Ar age.",YA002,23,Yakutat,Igneous,1300
Tfd,Felsic dikes,Eocene (?) and Paleocene,"Leucocratic dikes, sills, and small stocks that are not obviously connected to large intrusive bodies are found throughout the Valdez Group flysch and locally in Orca Group flysch. They are usually prophyyritic with fine- to medium-grained phenocrysts of plagioclase and occasional hornblende. The groundmass is usually a very fine-grained, sometimes felted mat of felsic minerals. Extensive secondary sericite and calcite often replace the felsic minerals; the scarce mafic minerals are almost completely altered to chlorite. Dacitic compositions dominae but more rhyolitic compositions can also be found. In Orca Group generally contain quartz and plagioclase phenocrysts in an alkali feldspar-rich fine-grained groundmass.",,Five K/Ar dates (three whole rock and two muscovite) ranging from 43.6 + or - 1.6 to 54.8 + or - 2.7 Ma.,VA003,6455,Valdez,Igneous,1301
Tqd,Quartz diorite,Eocene,"Foliate, fine- to medium-grained, seriate, hypidiomorphic, biotite-hornblende quartz diorite on south face of Mount Saint Elias.",,,MS002,97,Mount Saint Elias,Igneous,1308
Tt,Altered biotite and hornblende tonalite,Eocene,"Small, sericitized hornblende-biotite tonalite plugs. Rocks are fine- to medium-grained sericitized tonalite with minor quartz diorite and granodiorite. In most sample, muscovite replaces biotite or has formed from alteration of plagioclase.",,K-Ar hornblende 46.6 +/- 1.4 and muscovite of 52.4 +/- 2.6 Ma,VA002,1310,Valdez,Igneous,1310
Tsq,Snag Creek Pluton,Tertiary,Medium- to coarse-grained leucocratic biotite quartz monzonite,,K-Ar dates give minimum age of about 50 m.y.,NB002,158,Nabesna,Igneous,1320
Tgt,Granite and tonalite (Tonalite),Eocene,"Consists of Alsek River pluton of strongly foliate, medium-grained, equigranular, hypidiomorphic muscovite-biotite granite and the Novatak Glacier pluton of foliate, fine- to medium-grained, equigranular to seriate, hypidiomorphic hornblende-biotite tonalite. (Separated for NSA)",,"Alsek River pluton has yielded a middle Tertiary K-Ar date, hornblende from the Novatak glacier pluton gave a 61 Ma K-Ar age.",YA002,24,Yakutat,Igneous,1350
Tmu,Mafic and ultramafic plutonic rocks,Eocene and Paleocene?,"Mafic and ultramafic plutonic rocks-- Compositionally and texturally variable unit consists mainly of medium grained gabbro, local diabase, hornblende gabbro, peridotite, and orthopyroxenite. Gabbro is slightly to moderately foliated except near contacts with country rock.",,,CV003,210,Cordova,Igneous,1380
Tc,Cottonwood Creek Complex,Tertiary,Banded granite and quartz diorite gneiss and biotite- and augite-bearing amphibolite gradational into biotite metagranodiorite and metagranite. Weakly metamorphosed (greenschist facies).,,K-Ar of metamorphic biotite and amphibole of 17 to 20 m.y.,NB002,149,Nabesna,Metamorphic,1410
d,Dikes,Tertiary or Cretaceous,"Dikes of hornblende-feldspar porphyry, probably andesite to dacite in composition.",,,NB004,418,Nabesna,Igneous,1601
TKp,Older Porphyry,Tertiary or Cretaceous,"Baultoff Creek region is highly altered chlorite, carbonate mineral, and zoisite matrix with plagioclase phenocrysts. Chisana region is an andesite porphyry with plagioclase phenocrysts. May be a hypabyssal equivalent to the Chisana Formation",,,NB002,127,Nabesna,Igneous,2520
TKg,Felsic granitic rocks,Tertiary and Cretaceous,Felsic granitic rocks,,,MS002,41,Mount Saint Elias,Igneous,1655
TKg,Graphic granodiorite,Tertiary or Cretaceous,Hornblende granodiorite with graphic quartz and potassium feldspar,,,NB002,128,Nabesna,Igneous,2520
TKd,Diorite (undifferentiated),Tertiary and Cretaceous,"Porphyritic to eqyigranular granitic intrusives that are predominantly augite-hornblende diorite, equigranular hornblende diorite, augite-olivine syenodiorite, and augite bearing norite",,,NB002,129,Nabesna,Igneous,2520
TKm,Orca Group -- melange,Tertiary or Cretaceous,"Consists of extensive serpentinized ultramafic rocks including dike-like bodies of rodingite, as well as blocks of layered gabbro, crossite schist, pillow basalt, marble, chert of probable Late Triassic or Early Jurassic age, and diverse metamorphosed and virtually unmetamorphosed sedimentary rocks, including conglomerate that resembles lithologies within the Ckickaloon Formation of Paleocene age.",,,VA002,1710,Valdez,Tectonite,1790
Ku,Predominantly Upper Cretaceous sedimentary rocks,Cretaceous,"Parts of the Matanuska-Wrangell terrane; locally subdivided into Moonshine Creek Formation: siltstone and sandstone, with minor conglomerate; Schulze Formation: porcellanite, with minor sandstone and conglomerate; Chititu Formation: mudstone and shale, subordinate porcellanite, sandstone, and impure limestone; MacColl Ridge Formation: Coarse sandstone and minor granule and pebble conglomerate. Correlates to part of the Matanuska Formation in the Talkeetna Mtns, Matanuska Valley, and probably with rocks of the Matanuska geosyncline",'Abundant fossils' indicate an age span from late Albian to Maestrichtian,,MC002,17,McCarthy,Sedimentary,1940
Ks,Continental sedimentary rocks,Late Cretaceous,"Conglomerate, coarse- to fine-grained sandstone, siltstone, mudstone, and subordinate shale",Petrified wood; well preserved leaves and plants,,NB002,116,Nabesna,Sedimentary,1941
TKs,Continental sedimentary rocks,Tertiary and Cretaceous,"Predominantly conglomerate, grit, and coarse sandstone. Conglomerate ranges from clast-supported massive beds to bedded conglomerate sandstone. Clasts (up to 20 cm) rounded to subrounded crystalline rock, gneiss, gray chert, greenstone, and quartz (Cret. or older). Intruded by hornblende dacite sills in lower Rocker Creek",fragments of lignitized wood (up to 30 cm long) locally abundant,,MC003,307,McCarthy,Sedimentary,1941
Kun,Nonmarine sedimentary rocks - Wrangellia Terrane,Late Cretaceous,"Conglomerate, sandstone, siltstone, and mudstone",Locally contains abundant fossils,,GU003,336,Gulkana,Sedimentary,1941
Kmu,Matanuska Formation -- upper part,Late Cretaceous -- mid-Coniacian to Maestrichtian,"A very thick sequence of marine siltstone, claystone, and sandstone in interbedded with lenticular and channelized deposits of sandstone and conglomerate. Contact with lower part of unit presumed to an unconformity. Deposition thought to occur on the fringes of a deep-sea fan. Thinly interbedded siltstone, claystone, and sandstone, which predominate, represent deposition in interchannel areas; whereas thick beds and lenses of sandstone and conglomerate represent distributary channels.",,,VA002,2011,Valdez,Sedimentary,2010
Kml,Matanuska Formation -- lower part,"Cretaceous -- late-early-Albian, Cenomanian, Turonian, and early Coniacian","Marine siltstone, shale, sandstone, and pebbly sandstone are interbedded with subordinate silicieous, foraminiferal shale and fine-grained zeolitized sandstone. Contact with upper part of unit (unit Kmu) presumed to be an unconformity and is angular unconformity with the lower Talkeetna Formation (unit Jtk).",,,VA002,2012,Valdez,Sedimentary,2010
Kl,Lower Cretaceous sedimentary rocks,Early Cretaceous,"Parts of the Matanuska-Wrangell terrane; locally subdivided into unnamed Neocomian rocks: sandstone, shale, and impure bioclastic limestone with Inoceramus; (Albian) Kennecott Formation: sandstone, siltstone, minor basal and intraformational conglomerate, and shale. Correlates to much in Matanuska geosyncline and Matanuska formation in Talkeetna Mtns","Neocomian rocks: Inoceramus and other fossils that indicate Hauterivian and barremian; Kennecott Formation: Moffitites robustus, and Brewericeras hulenense",,MC002,16,McCarthy,Sedimentary,2110
Km,Matanuska Formation,Cretaceous,Matanuska Formation,,,GU002,176,Gulkana,Sedimentary,2010
Ks,Sedimentary rocks,Early Cretaceous,"Principally shallow marine and/or terrestrial in origin. The shallow marine rocks consist of thin-bedded brownish-weathering light-gray shaly siltstone and gray mudstone which interbeds with quartz-rich arkosic sandstone, grit and conglomerate. Locally carbonaceous containing abundant concretions. Shallow marine and/or terrestrial rocks consist chiefly of thin-bedded gray sitlstone, brown locally calcareous sandstone, and lenses of conglomerate. No marine fossils. One location was cut by a dacite dike (Qdd)","Ammonites, Brewericeras hulenense and Puzosia alaskana of late early Albian age were found in the shallow marine rocks. Fragments of lignitized wood is very abundant in the shallow marine and/or terrestrial rocks",,GU101,146,Gulkana,Sedimentary,2010
Kk,Kennicott Formation,"Early Cretaceous, Albian","Dominantly sandstone (fine-grained feldspathic graywacke and arkosic wacke) and siltstone, but includes shale and some conglomerate, whose clasts are predominantly Nikolai Greenstone, at the base. Generally dark greenish gray and weathers to brown; is thin-bedded; and has crude graded bedding, cross-bedding, sole markings, and spherical limy concretions. Represents fairly rapid shallow marine deposition in a transgressive sea",The pelecypods of the genus Aucellina represents the older of the two Albian faunal zones,,MC100,110,McCarthy,Sedimentary,2101
Kkp,Kuskulana Pass Formation,"Early Cretaceous, Neocomian, Barremian and Hauterivian","Thin bedded sandstone (very fine grained, dark greenish gray, arkosic-subordinate calcareous arkosic-lithic wacke), siltstone, and subordinate shale. Limy lenses and small spheroidal concretions are sparsely distributed. Locally cut by Tertiary hypabyssal rocks. The unit reflects fairly rapid shallow marine deposition",Meager ammonite and pelecypod fauna indicate Hauterivian and Barremian Stages of the Early Cretaceous; more definitive ammonite from C-7 document the Barremian Stage,,MC100,111,McCarthy,Sedimentary,2102
Kb,Berg Creek Formation,Early Cretaceous,"Marine clastic rocks consisting of calcareous conglomerate, conglomeratic sandstone and siltstone, and calcarenite. Basal strata generally are pebble, cobble, and boulder conglomerate consisting of clasts derived from nearby bedrock.",Inoceramus,,VA002,2110,Valdez,Sedimentary,2110
Js,Unnamed Jurassic marine sedimentary rocks,Middle Jurassic (Callovian)?,"Marine clastic rocks consisting mostly of sandstone, siltstone, and mudstone, which contain many interbeds of pebble- and cobble-conglomerate. Greenish-gray sandstone predominates in lower part of the sequence, in many places it is calcareous and cross-stratified. Highest rocks in the sequence include rusty-gray weathering limey siltstone interbeds and concretions. Rock strata in upper part are tightly folded into southeast-striking chevrons and isoclines",Unnamed Callovian fossils,,VA002,3120,Valdez,Sedimentary,2110
Kl,Clastic sedimentary rocks ,Early Cretaceous,"Dark greenish-gray to very dark gray shale, locally concretionary, with subordinate siltstone, arkosic sandstone, and arkosic granule- to pebble conglomerate. Chocolate-brown to reddish-brown weathering colors and hackly to slaty cleavage are conspicuous in the shale, completely obscuring bedding in most places. Locally contain thin coquina and carbonaceous detritus, particularly in sandstone and pebble conglomerate beds near base of unit. Thickness unknown, but exceeds 200 meters. Presumed to correlate with unnamed Neocomian rocks that occur in scattered exposures in the adjacent McCarthy quadrangle (MacKevett, 1978) and extend westward as far as the mouth of the Chitina River (Grantz and others, 1966) and eastward into adjacent parts of Canada (Campbell and Dodds, 19 ) and the St. Elias Mountains (Sharp and Rigsby, 1956).",Contains sparse but diverse megafauna of probable Neocomian age,,BG002,163,Bering Glacier,Sedimentary,2110
Ks,Marine sedimentary rocks,Early Cretaceous,Wrangellia terrane. Consists of Berg Creek Formation and unnamed marine sedimentary rock,,,VA007,38,Valdez,Sedimentary,2110
Kbc,Berg Creek Formation,"Early Cretaceous, Neocomian, Barremian and Hauterivian","Medium bedded with occasionaly cross-bedding, rocks consist of limestone (well sorted, light gray, impure bioclastic sandy grainstone) and subordinate verigated green-gray-brown pebble basal conglomerate. The formation probably formed in near-shore environments of a transgressive sea, where the limestone could have been a near-shore shoal or bar. Berg Creek correlates with the Nelchina Limestone in the Talkeetna Quad","Abundant and dominant Inocerimus as well as Pinna, Simbirskites, and belemnites. Fossils indicate the Hautervian and Barremian Stages of the Early Cretaceous",,MC100,112,McCarthy,Sedimentary,2110
Kbc,"Bernard Creek terrane, deleted, now McHugh Complex",mid-Cretaceous?,"Mylonitic greenschist. Relict bedding and volcaniclastic textures are retained locally. Elsewhere unit is nearly massive, but cataclasis and neomineralization generally are so pervasive that they obliterate any primary features.",,,VA005,2190,Valdez,Metamorphic,2190
KJm,McHugh Complex,Early Cretaceous and Jurassic?,"Pervasively deformed assemblage of diverse lithologies (melange). Lithologies include gabbro, greenstone, marble, wacke, and diverse plutonic and metamorphic rocks including blueschist. Rocks occur in three discrete belts, the northernmost which yields Triassic radiolarians, a medial belt yielding Jurassic and Cretaceous age, and a southernly belt yielding radiolaria as young mid-Cretaceous age. Rocks typically shown prehnite-pumpellyite facies metamorphism.",Radiolaria from chert ranges from Triassic to mid-Cretaceous (Albian or Cenomanian).,,VA002,2190,Valdez,Tectonite,2190
Mzm,McHugh Complex ,Early(?) Cretaceous to Late Jurassic,"A structurally chaotic melange-like unit of accreted oceanic rocks that crops out in a narrow belt to about 1.5 km wide. The complex consists of pervasively disrupted broken formation that originally was mainly tholeiitic pillowed basalt and related fragmental volcanic rocks containing subordinate amounts of argillite, tuff or tuffaceous argillite, radiolarian chert, graywacke, mudstone, siltstone, and carbonate rocks. The unit was originally defined in the Anchorage area by Clark (1973) and subsequently geographically extended to comparable rocks that crop out discontinuously along the north margin of the Chugach and Kenai Mountains (Plafker and others, 1994).",,,BG002,148,Bering Glacier,Tectonite,2190
Mzpg,Phyllite/greenstone melange,Early(?) Cretaceous to Late Jurassic,"Structurally chaotic melange-like unit of dominantly massive medium- to dark-green metabasalt interbedded with gray to black metapelitic rocks and intercalated minor gray to white metachert; occurs structurally between the McHugh Complex and Valdez Group. Structural thickness is up to 2.5 km, and thickness of the dominantly greenstone units is as much as 600 m. . Metamorphic grade is lower greenschist facies",,,BG002,147,Bering Glacier,Tectonite,2191
Kc,Chisana Formation,Early Cretaceous,Thin- to medium-bedded andesite flows and diverse volcanoclastic rocks. Probably represents Klein Creek and related mid-Cretaceous plutons of Nabesna Quad. Widespread in Nabesna Quad.,,,MC002,14,McCarthy,Igneous,2340
Kc,Chisana Formation,Early Cretaceous,"Subaqueous and subaerial volcanic and volcaniclastic rocks; Upper Part: primarily andesite, basaltic andesite flows, fragmental volcanic rocks, suordinate porphyritic andesite, thin-bedded conglomerate, grit, sandstone, and tuff. Lower Part: fragmental volcanic rocks, dacite to andesite porphorytic flows, volcanic sandstone and siltstone, argillite, graywacke, conglomerate, and a tuffaceous mudstone",Lignitized wood; Inoceramus; Shasticrioceras,,NB002,117,Nabesna,Igneous,2340
Kc,Chisana Formation,Lower Cretaceous,"Volcanic flows, massive volcanic breccias, and minor interbedded volcaniclastic rocks. Dominantly andesites and basaltic andesites, generally containing conspicuous augite phenocrysts",,,NB108,538,Nabesna,Igneous,2340
Kc,Chisana Formation,Early Cretaceous,"Andesite flows, fragmental volcanic rocks, and volcaniclastic rocks locally strongly propylitized",,,NB109,338,Nabesna,Igneous,2340
Kvu,Valdez Group: Ultramafic rocks,Late Cretaceous,VALDEZ GROUP: Serpentinized peridotite and dunite occur at three localities underlain by the Valdez Group: two of these are on the Resurrection Peninsula and the third is near the head of Port Fidalgo. On the Resurrection Peninsula small sparse inclusions of altered dunite are found in the gabbro unit. Blocks of serpentinite and serpentinized peridotite crop out within the interbedded volcanic and sedimentary rocks unit. Their strongly shared margins suggest that these rocks have been tectonically emplaced. The third outcrop of ultramafic rocks is northeast of the head of Port Fidalgo. This outcrop consists of both banded and massive dark- to light-green serpentized dunite and peridotite. ultramafic rocks,,,CV002,553,Cordova,Igneous,2440
Kug,Undifferentiated Plutonic rocks,Cretaceous (?),"Porphoritic medium-grained biotite-hornblende granodiorite, coarse-grained ophitic gabbro, and medium-grained, weakly foliated biotite-rich granodiorite-diorite",,,NB002,164,Nabesna,Igneous,2460
Kgq,Gardiner Creek Pluton,Cretaceous,Part of the Middle Cretacous plutonic event. Rocks are mainly foliated quartz monzonite. Also coarse-grained leucocratic biotite quartz monzonite,,K-Ar dates indicate emplacement of 89 to 94 m.y.,NB002,159,Nabesna,Igneous,2475
Kcg,Cheslina Pluton,Cretaceous,Part of the Middle Cretacous plutonic event. Rocks are mainly foliated quartz monzonite. Also medium-grained biotite-hornblende granodiorite with hornblende monzonite,,K-Ar dates indicate emplacement of 89 to 94 m.y.,NB002,160,Nabesna,Igneous,2475
Ktq,Tok-Tetlin Pluton (Tetlin phase),Cretaceous,Porphhyritic biotite-hornblende quartz monzonite locally gradational to biotite-hornblende granodiorite,,K-Ar dates indicate emplacement of 92 to 94 m.y.,NB002,161,Nabesna,Igneous,2475
Kmg,Tok-Tetlin Pluton (Mineral Cairn phase),Cretaceous,Porphyritic biotite-hornblende granodiorite and quartz monzonite with minor biotite diorite,,K-Ar dates indicate emplacement of 92 to 94 m.y.,NB002,163,Nabesna,Igneous,2475
Ktg,Tok-Tetlin Pluton (Tok phase),Cretaceous,Fine- to medium-grained biotite-hornblende granodiorite,,K-Ar dates indicate emplacement of 92 to 94 m.y.,NB002,162,Nabesna,Igneous,2475
Ktm,"Tok-Tetlin Pluton, Mineral Cairn phase",Cretaceous,Mineral Cairn phase. Chiefly granodiorite but gradational into diorite and quartz monzonite. Rocks are weakly to strongly foliated.,,"K-Ar dates indicate an emplacement age of 92-94 m.y. (Richter and others, 1975)",NB004,420,Nabesna,Igneous,2475
Ktt,"Tok-Tetlin Pluton,Tetlin phase.",Cretaceous,"Tetlin phase. Poyphyritic quartz monzonite with abundant and conspicuous orthoclase phenocrysts in a medium- to coarse-grained hypidiomorphic-granular matrix of plagioclase, quartz, biotite, and hornblende. Rocks are non-foliated.",,,NB004,421,Nabesna,Igneous,2475
Kg,Altered tonalite,Cretaceous,"Fine- to medium-grained, equigranular to seriate, hypidiomorphic and foliate hornblende-biotite tonalite. Mafic grains are oriented; most samples are pervasively sheared and altered along fractures. Intrude Yakutat Group melange facies.",,K-Ar age reported on something related to pluton at 100 Ma (report unclear),YA002,43,Yakutat,Metamorphic,2493,,ALT
Kum,Ultramafic rocks,Cretaceous (?),"Serpentinite, serpentinized periodotite, and dunite, with subordinate clinopyroxenite",,,NB002,165,Nabesna,Igneous,2510,,
Kvu,Valdez Group: Ultramafic rocks,Late Cretaceous,Serpentinized peridotite and dunite occur at three localities underlain by the Valdez Group: two of these are on the Resurrection Peninsula and the third is near the head of Port Fidalgo. On the Resurrection Peninsula small sparse inclusions of altered dunite are found in the gabbro unit. Blocks of serpentinite and serpentinized peridotite crop out within the interbedded volcanic and sedimentary rocks unit. Their strongly shared margins suggest that these rocks have been tectonically emplaced. The third outcrop of ultramafic rocks is northeast of the head of Port Fidalgo. This outcrop consists of both banded and massive dark- to light-green serpentized dunite and peridotite. ultramafic rocks,,,CV002,553,Cordova,Igneous,2510,,
Kkg,Klein Creek Pluton,Cretaceous,"Medium grained, hypidiomorphic granular, unfoliated hornblende-biotite granodiorite and quartz monzonite. Coextensive with, or satellites of, the Klein Creek intrusive of Nabesna Quad.",,Nabesna Quad date of 111+3 m.y.,MC002,15,McCarthy,Igneous,2520,,
Ksg,Slana Pluton,Cretaceous,Part of a Middle Cretaceous plutonic event. Equigranular hornblende granodiorite. Locally weakly foliated,,,NB002,130,Nabesna,Igneous,2520,,
Kas,Antler Creek Pluton,Cretaceous,Part of a Middle Cretaceous plutonic event. Equigranular hornblende syenodiorite. Weakly foliated,,K-Ar data yields ages between 105 and 117 m.y.,NB002,138,Nabesna,Igneous,2520,,
Kah,Border of Antler Creek Pluton,Cretaceous,Part of a Middle Cretaceous plutonic event. Coarse-grained hornblendite,,,NB002,139,Nabesna,Igneous,2520,,
Kkg,Klein Creek Pluton,Cretaceous,"Part of a Middle Cretaceous plutonic event. Equigranular hornblende-biotite granodiorite and quartz monzonite with minor hornblende syenodiorite, biotite gabbro, and hornblende diorite",,K-Ar data yields ages between 105 and 117 m.y.,NB002,140,Nabesna,Igneous,2520,,
Kng,Nabesna Pluton,Cretaceous,"Part of a Middle Cretaceous plutonic event. Equigranular hornblende-biotite granodiorite with quartz diorite, diorite, and trondhjemite. Propylitic and argillic alteration common",,K-Ar data yields ages between 105 and 117 m.y.,NB002,133,Nabesna,Igneous,2520,,
Kg,Granodiorite pluton,Cretaceous (?),"Granodiorite pluton, Wrangellia terrane",,,GU002,137,Gulkana,Igneous,2520,,
Kkg,Klein Creek pluton,Cretaceous,Hornblende-biotite granodiorite and quartz monzonite.,,K-Ar ages indicate emplacement age of 105-117 Ma,MC003,326,McCarthy,Igneous,2520,,
Kg,Granodiorite,Lower Cretaceous,Medium grained biotite-hornblende granodiorite with hypidiomorphic-granular texture; locally weakly to strongly foliated,,K-Ar date indicates age of 125 +/- 4 my,GU101,147,Gulkana,Igneous,2520,,
Kg,Granodiorite and quartz diorite,Cretaceous,"Fine to medium-grained, subhedral, granular rocks containing hornblende, plagioclase, and quartz, with minor biotite, augite, and potassium feldspar. Chloritization and saussuritization common. Host marine sedimentary rocks (KJs), limestone (Trtl, Trml), and Nikolai Greenstone (Trn) have been extensively thermally metamorphosed, and locally contain masses, veins, and segregations of sulfide minerals.",,,NB108,537,Nabesna,Metamorphic,2520,,ALT
Knp,Quartz-feldspar porphyry,Cretaceous,"Part of a Middle Cretaceous plutonic event. Equigranular, quartz-feldspar, porphyry with altered plagioclase",,,NB002,134,Nabesna,Igneous,2525,,
Kbd,Buck Creek Pluton,Cretaceous,"Part of a Middle Cretaceous plutonic event. Equigranular hornblende quartz diorite and syenodiorite, and subordinate leucocratic hornblende granodiorite. Locally strongly foliated",,,NB002,131,Nabesna,Igneous,2540,,
Ksd,Suslota Pass Pluton,Cretaceous,Part of a Middle Cretaceous plutonic event. Equigranular hornblende diorite,,K-Ar data yields ages between 105 and 117 m.y.,NB002,132,Nabesna,Igneous,2540,,
Kdd,Devils Mountain Pluton,Cretaceous,"Part of a Middle Cretaceous plutonic event. Equigranular hornblende diorite, quartz diorite, and hornblende granodiorite. Strongly porpytically altered.",,K-Ar data yields ages between 105 and 117 m.y.,NB002,136,Nabesna,Igneous,2540,,
Kcs,Chisana Pluton,Cretaceous,"Part of a Middle Cretaceous plutonic event. Equigranular clinopyroxene diorite, clinopyroxene syenodiorite, and clinopyroxene-hornblende monzonite",,K-Ar data yields ages between 105 and 117 m.y.,NB002,137,Nabesna,Igneous,2540,,
Kkd,Hornblende-rich diorite,Cretaceous,Part of a Middle Cretaceous plutonic event. Equigranular hornblende-rich diorite,,,NB002,141,Nabesna,Igneous,2540,,
Kd,Horneblende Diorite,Cretaceous (?),"Small stocks, chiefly of hornblende diorite. Hornblende largely altered to chlorite.",,,NB004,419,Nabesna,Igneous,2540,,
Ku,Undifferentiated Granitic Rocks,middle Cretaceous,Chiefly altered quartz diorite and granodiorite,,,NB109,337,Nabesna,Igneous,2540,,ALT
Knt,Trondhjemite,Cretaceous,"Part of a Middle Cretaceous plutonic event. Medium- to coarse-grained leucocratic trondhjemite with sodic plagioclase, quartz, and biotite",,,NB002,135,Nabesna,Igneous,2570,,
KTj,Trondhjemite ,Tertiary or middle Cretaceous,"White (C.I. 0-5), fine-to medium grained, small trondhjemite stoks and associated dikes consisting of plagioclase and -quartz with sparse biotite and white mica in the southeastern part of the D-2 quadrangle",,,BG002,300,Bering Glacier,Igneous,2570,,
Kfc,Fox Creek terrane Unit deleted on new VA map,mid-Cretaceous?,"Intercalcated lower greenschist and transistional blueschist facies metasedimentary and mafic metavolcanic rocks. Over broad areas the rocks have a cataclastic fabric, locally relict primary sedimentary and volcaniclastic textures are retained. Unit is distinguished from Bernard Creek terrane (unit Kbc) by the dominance of dark, very-fine-grained metapelitic rocks; where green metavolcanic rocks are present in the Fox Creek terrane they indistinguishable from greenschist of the Bernard Creek terrane.",,,VA005,2700,Valdez,Metamorphic,2700,,
Khc,Haley Creek terrane,mid-Cretaceous?,"Metamorphosed complexly deformed and tectonically mixed plutonic and sedimentary rocks. Metaplutonic rocks are most abundant in southern part of the terrane and are compositionally diverse and weakly to strongly foliated. Although diorite and granodiorite are most abundant lithologies, compositions range from trondjhemite to hornblende gabbro and hornblendite. Amphibolite is is widespread within the metaplutonic rocks. Metasedimentary rocks are dominant in northern part of terrane where marble, metapelite, metapsammite are structurally mixed with subordinate metaplutonic rocks. Unit deleted and merged with Jag (NSA = 5245)",,,VA002,2700,Valdez,Metamorphic,5245,,
Kvs,"Valdez Group -- Metasedimentary rocks, undivided",Late Cretaceous,"Weakly to strongly foliated marine argillite, siltstone, sandstone, and conglomeratic sandstone. Lower greenschist facies metamorphism. Probable volcanic source terrane.",Maestrichtian pelecypods collected outside of Valdez quadrangle.,,VA002,2700,Valdez,Metamorphic,2700,,
Kvm,Valdez Group -- Phyllite and schist. Delete unit on new VA map,Late Cretaceous,Low-grade metamorphosed (lower greenschist facies) pelitic rocks consisting of homogeneous phyllite and schist. These rocks shown much stronger foliation than the undivided metasedimentary rocks (unit Kvs) of the Valdez Group. Probable volcanic source terrane.,,,VA002,2701,Valdez,Metamorphic,2700,,
KJv,Valdez Group,Cretaceous and Jurassic (?),"Thin- to medium-bedded metamorphosed flysch, interlayered metagraywacke and argillite, minor schist, slate, and phyllite; metamorphosed to chlorite- or biotite-grade greenschist-facies mineral assemblages",'Metafossils' recorded by Jones and Clark (1973) yield Maestrichain age,,MC002,12,McCarthy,Metamorphic,2700,,
Kv,Valdez Group -- Metaflysch,Late Cretaceous,Mainly phyllitic metapelite (70-80 percent) and subordinate metagraywacke in thin to very thick beds with minor metavolcanic rocks metamorphosed mainly to lower greenschist facies. Locally hornfelsed and massive near Tertiary plutons. The metapelite is dark gray to black and consists mainly of carbonaceous phyllite and lesser amounts of slate and very fine grained mica schist.,,,BG002,142,Bering Glacier,Metamorphic,2700,,
Kvs,"Valdez Group: Metasedimentary rocks, undivided",Late Cretaceous,"Thick sequence of rhythmically alternating, multiply-deformed, metamorphosed turbidites that consist of metasandstone, metasiltstone, argillite, slate and phyllite and rare beds of pebbly argillite. Beds generally a few centimeters to a few meters thick. Primary internal sedimentary structures are common. Variably metamorphosed regionally from zeolite to lower greenschist facies.",,,CV003,511,Cordova,Metamorphic,2700,,
Kvs,"Valdez Group: Sedimentary rocks, undivided",Late Cretaceous,"Thick sequences of deformed and metamorphosed flysch consisting of metasandstone, metasiltstone, argillite, slate, and phyllite, with rare beds of conglomerate and pebbly argillite. In many places primary internal sedimentary structures, consisting of graded bedding, cross laminations, and convolute bedding are preserved. All sedimentary rocks studied contain metamorphic biotite. The sandstones display a moderately developed semischistose texture that has abundant randomly oriented interstitial biotite and less abundant weakly aligned biotite. Sandstones range from lithic to feldspatholithic in composition. Samples become less lithic-rich and more feldspar- and quartz-rich from west to east.","Pelecypod: Inoceramus kusiroensis, Inoceramus ulrichi, and Inoceramya concentrica",K/Ar date on biotite semischist of 51.5 + or - 1.5 Ma,CV002,510,Cordova,Sedimentary,2700,,
Kvs,"Valdex Group: Sedimentary rocks, undivided",Late Cretaceous,"VALDEZ GROUP: Thick sequences of deformed and metamorphosed flysch consisting of metasandstone, metasiltstone, argillite, slate, and phyllite, with rare beds of conglomerate and pebbly argillite. In many places primary internal sedimentary structures, consisting of graded bedding, cross laminations, and convolute bedding are preserved. All sedimentary rocks studied contain metamorphic biotite. The sandstones display a moderately developed semischistose texture that has abundant randomly oriented interstitial biotite and less abundant weakly aligned biotite. Sandstones range from lithic to feldspatholithic in composition. Samples become less lithic-rich and more feldspar- and quartz-rich from west to east.","Pelecypod: Inoceramus kusiroensis, Inoceramus ulrichi, and Inoceramya concentrica",K/Ar date on biotite semischist of 51.5 + or - 1.5 Ma,BG003,510,Bering Glacier,Sedimentary,2700,,
Kvs,"Valdez Group: Sedimentary rocks, undivided",Late Cretaceous,"VALDEZ GROUP: Thick sequences of deformed and metamorphosed flysch consisting of metasandstone, metasiltstone, argillite, slate, and phyllite, with rare beds of conglomerate and pebbly argillite. In many places primary internal sedimentary structures, consisting of graded bedding, cross laminations, and convolute bedding are preserved. All sedimentary rocks studied contain metamorphic biotite. The sandstones display a moderately developed semischistose texture that has abundant randomly oriented interstitial biotite and less abundant weakly aligned biotite. Sandstones range from lithic to feldspatholithic in composition. Samples become less lithic-rich and more feldspar- and quartz-rich from west to east.","Pelecypod: Inoceramus kusiroensis, Inoceramus ulrichi, and Inoceramya concentrica",K/Ar date on biotite semischist of 51.5 + or - 1.5 Ma,CV002,510,Cordova,Sedimentary,2700
Kvs,"Valdez Group: Sedimentary rocks, undivided",Late Cretaceous,"VALDEZ GROUP: Thick sequences of deformed and metamorphosed flysch consisting of metasandstone, metasiltstone, argillite, slate, and phyllite, with rare beds of conglomerate and pebbly argillite. In many places primary internal sedimentary structures, consisting of graded bedding, cross laminations, and convolute bedding are preserved. All sedimentary rocks studied contain metamorphic biotite. The sandstones display a moderately developed semischistose texture that has abundant randomly oriented interstitial biotite and less abundant weakly aligned biotite. Sandstones range from lithic to feldspatholithic in composition. Samples become less lithic-rich and more feldspar- and quartz-rich from west to east.","Pelecypod: Inoceramus kusiroensis, Inoceramus ulrichi, and Inoceramya concentrica",K/Ar date on biotite semischist of 51.5 + or - 1.5 Ma,VA003,6510,Valdez,Sedimentary,2700
Kvvm,Valdez Group -- Interbedded metavolcanic and metasedimentary rocks-,Late Cretaceous,"Approximately equal amounts of interbedded metavolcanic and metasedimentary rocks. Metavolcanic rocks are chiefly semischistose metatuff and breccia, including local probable pillow lava. Metasedimentary rocks chiefly slate and phyllite, although metasiltstone and metasandstone are interbedded in many places. Dominantly greenschist facies metamorphism.",,,BG002,145,Bering Glacier,Metamorphic,2702
Kvvs,Valdez Group: Interbedded metavolcanic and metasedimentary rocks,Late Cretaceous,"Equal proportions of interbedded metavolcanic and metasedimentary rocks. Metavolcanic--semischistose metatuff and breccia and minor pillow basalt. Metasedimentary--slate, phyllite, with metasilstone and metasandstone interbedding. Variable metamorphic grades.",,,CV003,555,Cordova,Metamorphic,2702
Kvvs,Valdez Group: Interbedded volcanic and sedimentary rocks,Late Cretaceous,"This unit is composed of approximately equal amounts of interbedded volcanic rocks, consisting of volcanic breccia, tuff, tuffaceous sediment, and minor pillow basalt, and sedimentary rocks, consisting of sandstone, siltstone, shale, and chert. The two exposures of the unit differ in character. In the Cordova quadrangle the unit tends to weather orange and includes more sedimentary rocks (including marble) than on the Resurrection Peninsula. Near the head of Port Fidalgo this unit has been metamorphosed to amphibote-bearing greenschist.",,K-Ar date on amphibote-bearing greenschist of 47.6 +/- 1.4 Ma,CV002,554,Cordova,Igneous,2702
Kvvs,Valdez Group: Interbedded volcanic and sedimentary rocks,Late Cretaceous,"VALDEZ GROUP: This unit is composed of approximately equal amounts of interbedded volcanic rocks, consisting of volcanic breccia, tuff, tuffaceous sediment, and minor pillow basalt, and sedimentary rocks, consisting of sandstone, siltstone, shale, and chert. The two exposures of the unit differ in character. In the Cordova quadrangle the unit tends to weather orange and includes more sedimentary rocks (including marble) than on the Resurrection Peninsula. Near the head of Port Fidalgo this unit has been metamorphosed to amphibote-bearing greenschist.",,K-Ar date on amphibote-bearing greenschist of 47.6 + or - 1.4 Ma,CV002,554,Cordova,Igneous,2702
Kvv,"Valdez Group -- Metavolcanic rocks, undivided",Late Cretaceous,Mafic metatuff and minor massive or weakly foliated greenstone having rarely preserved vague pillow shapes. Lower greenschist facies metamorphism. Most of these metavolcanic rocks are schistose and the metavolcanic are often the loci of intense deformation in the Valdez Group.,,K-Ar whole-rock age on metatuff of 53.5 +/- 1.6 Ma is thought to date matamorphism.,VA002,2705,Valdez,Metamorphic,2705
Kvv,"Valdez Group: Metavolcanic rocks, undivided",Late Cretaceous,"Tholeiitic metabasalt and basaltic metatuff, including local pillow lava, pillow brecia, and gabbroic dikes and sills. Metabasalt form rugged, nearly massive outcrops, whereas semischistose metatuff forms more subdued outcrops. Variable metamorphic grades.",,,CV003,515,Cordova,Metamorphic,2705
Kvgr,Valdez Group: Greenstone,Late Cretaceous,"This unit consists of massive greenstone, metamorphosed pillow basalt, and mafic dikes exposed near the heads of Woodworth and Schwan Glaciers. Elsewhere in the Cordova and Valdez quadrangles, the unit includes lenticular bodies of chorite schist that may have originally typically metamorphosed to greenschist and low amphibolite facies. The higher grade facies is distinguished by the presence of dark-green hornblende.",,,CV002,611,Cordova,Metamorphic,2705
Kvgr,Valdez Group: Greenstone,Late Cretaceous,"VALDEZ GROUP: This unit consists of massive greenstone, metamorphosed pillow basalt, and mafic dikes exposed near the heads of Woodworth and Schwan Glaciers. Elsewhere in the Cordova and Valdez quadrangles, the unit includes lenticular bodies of chorite schist that may have originally typically metamorphosed to greenschist and low amphibolite facies. The higher grade facies is distinguished by the presence of dark-green hornblende.",,,CV002,611,Cordova,Metamorphic,2705
Kvgr,Valdez Group: Greenstone,Late Cretaceous,"VALDEZ GROUP: This unit consists of massive greenstone, metamorphosed pillow basalt, and mafic dikes exposed near the heads of Woodworth and Schwan Glaciers. Elsewhere in the Cordova and Valdez quadrangles, the unit includes lenticular bodies of chorite schist that may have originally typically metamorphosed to greenschist and low amphibolite facies. The higher grade facies is distinguished by the presence of dark-green hornblende.",,,VA003,6611,Valdez,Metamorphic,2705
Kvm,Valdez Group -- Amphibolite schist,Late(?) Cretaceous,"Mostly massive, black to greenish-black fine- to medium-grained amphibolite schist Probably derived from massive basalt and gabbro. Coded as 2710 on WRST map",,,YA002,77,Yakutat,Metamorphic,2710
Kvm,Valdez Group -- Schistose metaflysch,Late Cretaceous,"Medium to medium-light gray, very fine- to medium-grained schistose metapelite, metagraywacke, and minor metatuff. Commonly weathers to blocky or tabular fragments and form banded gray outcrops streaked with iron-oxide stains.",,,BG002,143,Bering Glacier,Metamorphic,2710
Kvm,Valdez Group: Schist,Late Cretaceous,Homogenous pelitic schist and minor amphibolite; includes spotted biotite-plagioclase-quartz schist. Common banding probably represents original layering. Transitional into gneissose rocks to the east and into greenschist-facies rocks of metasedimentary rocks to the west.,,,CV003,600,Cordova,Metamorphic,2710
Kvm,Valdez Group -- Amphibolite schist,Late(?) Cretaceous,"Mostly massive, black to greenish-black fine- to medium-grained amphibolite schist Probably derived from massive basalt and gabbro.",,,MS002,77,Mount Saint Elias,Metamorphic,2710
Kvm?,Schist of Mount Augusta -- Amphibolite schist,Cretaceous(?),"Dark-greenish black, fine-grained, partially segregated amphibolite schist",,,MS002,69,Mount Saint Elias,Metamorphic,2710
Ksm,Valdez Group -- Pelitic and quartzofeldspathic schist and gneiss,Late Cretaceous,"Reddish weathering, varibly banded, strongly schistose to granoblastic pelitic and quartzofeldspathic schist and gneiss. Typically a garnetiferous graphitic schist. Sedimentary clastic protolith.",,,YA002,79,Yakutat,Metamorphic,2715
Kvm,"Valdez Group, amphibolite-facies flysch",Late Cretaceous,Dominantly schist. Flysch metamorphosed to lower greenschist facies,,,BG004,319,Bering Glacier,Metamorphic,2700
Kvg,Valdez Group -- Schistose to gneissic metaflysch and migmatite,Late Cretaceous,"Amphibolite-facies schist, banded gneiss, and migmatitic gneiss. Fine- to coarse-grained but mostly medium- to coarse-grained. Gray to light gray, and characteristically weathers rusty brown. Layering is irregular and inhomogeneous with discontinuous quartz-rich layers and lenses alternating with finer-grained, streaky, biotite -rich layers.",,,BG002,144,Bering Glacier,Metamorphic,2715
ap,SCHIST OF MOUNT AUGUSTA -- Pelitic schist,Cretaceous(?),"Reddish-weathering, quartzofeldspathic pelitic schist; characteristic assemblages consist of plagioclase (An 15), biotite, and quartz with accessory magnetite and sulfides. Locally contains porphyroblasts of euhedral garnet and poikilitic staurolite. Occurs in a large fault-bounded block of metavolcanic and metasedimentary rocks metamorphosed to dominantly epidote-amphibolite facies assemblages that are in part doubly foliated. Inferred to be correlative with the Valdez Group metamorphic rocks on basis of lithology, metamorphic grade, and structural style (Plafker and others, 1994).",,K-Ar dating of a biotite and hornblende pair in the adjacent Saint Elias quadrangle yields recrystallization ages of 17-23 m.y.,BG002,150,Bering Glacier,Metamorphic,2715
av,SCHIST OF MOUNT AUGUSTA -- Amphibolite schist,Cretaceous(?) and Jurassic(?),"Dark-greenish black, fine-grained, partially segregated, amphibolite schist having assemblages of hornblende and plagioclase (An > 15) with minor quartz, magnetite, and sphene. Probably mainly derived from mafic basaltic flow rocks. Occurs in a large fault-bounded block of metavolcanic and metasedimentary rocks metamorphosed to dominantly epidote-amphibolite facies assemblages that are in part doubly foliated. Inferred to be correlative with the Valdez Group metamorphic rocks on basis of lithology, metamorphic grade, and structural style (Plafker and others, 1994).",,K-Ar dating of a biotite and hornblende pair in the adjacent Saint Elias quadrangle yields recrystallization ages of 17-23 m.y.,BG002,151,Bering Glacier,Metamorphic,2715
avp,SCHIST OF MOUNT AUGUSTA -- Intercalated quartzofeldspathic schist and amphibolite,Cretaceous(?) and Jurassic(?),"Intercalated quartzofeldspathic schist and amphibolite. Large fault-bounded block of metavolcanic and metasedimentary rocks metamorphosed to dominantly epidote-amphibolite facies assemblages that are in part doubly foliated. Inferred to be correlative with the Valdez Group metamorphic rocks on basis of lithology, metamorphic grade, and structural style (Plafker and others, 1994).",,K-Ar dating of a biotite and hornblende pair in the adjacent Saint Elias quadrangle yields recrystallization ages of 17-23 m.y.,BG002,152,Bering Glacier,Metamorphic,2715
Kvg,Valdez Group: Gneiss,Late Cretaceous,"Muscovite-biotite-quartz-plagioclase (+/- sillimanite and garnet) schist, banded gneiss, and migmatitic gneiss; many local intrusive stringers, dikes, and sills of granodiorite and granite. Transitional into schistose rocks to the north, south, and west.",,,CV003,609,Cordova,Metamorphic,2715
Kvg,Valdez Group: Paragneiss,Late Cretaceous,"Predominantly metasedimentary rocks with well-developed gneissic foliation consisting of alternating quartz and feldspar-rich layers with biotite-rich layers. The paragneiss is brown weathering, medium grained, and banded on a 2 to 4 mm scale. However, thicker biotite-rich layers are also found. Quartz segregations parallel to the banding are common but not laterally continuous. Locally some layers in the paragneiss contain 1-in.-long porphyroblasts of andalusite. This unit contains up to 10 percent orthogneiss. The orthogneiss is cream colored or light gray, coarse grained, contains less biotite than the paragneiss, and locally grades into normal textured granitic rocks containing abundant inclusions of country rock.",,,CV002,610,Cordova,Metamorphic,2715
Kvg,Valdez Group: Paragneiss,Late Cretaceous,"VALDEZ GROUP: Predominantly metasedimentary rocks with well-developed gneissic foliation consisting of alternating quartz and feldspar-rich layers with biotite-rich layers. The paragneiss is brown weathering, medium grained, and banded on a 2 to 4 mm scale. However, thicker biotite-rich layers are also found. Quartz segregations parallel to the banding are common but not laterally continuous. Locally some layers in the paragneiss contain 1-in.-long porphyroblasts of andalusite. This unit contains up to 10 percent orthogneiss. The orthogneiss is cream colored or light gray, coarse grained, contains less biotite than the paragneiss, and locally grades into normal textured granitic rocks containing abundant inclusions of country rock.",,,BG003,610,Bering Glacier,Metamorphic,2715
Kvg,Valdez Group: Paragneiss,Late Cretaceous,"VALDEZ GROUP: Predominantly metasedimentary rocks with well-developed gneissic foliation consisting of alternating quartz and feldspar-rich layers with biotite-rich layers. The paragneiss is brown weathering, medium grained, and banded on a 2 to 4 mm scale. However, thicker biotite-rich layers are also found. Quartz segregations parallel to the banding are common but not laterally continuous. Locally some layers in the paragneiss contain 1-in.-long porphyroblasts of andalusite. This unit contains up to 10 percent orthogneiss. The orthogneiss is cream colored or light gray, coarse grained, contains less biotite than the paragneiss, and locally grades into normal textured granitic rocks containing abundant inclusions of country rock.",,,CV002,610,Cordova,Metamorphic,2715
Kvg/Tg,Valdez Group -- Schistose to gneissic metaflysch and migmatite and stockwork of dikes?,Late Cretaceous,"Amphibolite-facies schist, banded gneiss, and migmatitic gneiss. Fine- to coarse-grained but mostly medium- to coarse-grained. Gray to light gray, and characteristically weathers rusty brown. Layering is irregular and inhomogeneous with discontinuous quartz-rich layers and lenses alternating with finer-grained, streaky, biotite -rich layers. Intruded by stockwork of dikes.",,,BG002,146,Bering Glacier,Metamorphic,2715
Kvsm,Valdez Group -- Undifferentiated metavolcanic and metasedimentary rocks,Late Cretaceous,Largely interbedded mafic to intermediate metavolcanic rocks that were mainly volcaniclastic and metaclastic. Metasedimentary sequence locally includes metachert and thin lenses of marble.,,,MS002,81,Mount Saint Elias,Metamorphic,2715
Ksm,Valdez Group -- Pelitic and quartzofeldspathic schist and gneiss,Late Cretaceous,"Reddish weathering, varibly banded, strongly schistose to granoblastic pelitic and quartzofeldspathic schist and gneiss. Typically a garnetiferous graphitic schist. Sedimentary clastic protolith.",,,MS002,79,Mount Saint Elias,Metamorphic,2715
Kvsm?,Schist of Mount Augusta -- Interbedded quartzofeldspathic schist and amphibolite,Cretaceous(?),Reddish weathering doubly foliated quartzofeldspathic schist interbedded with amphibolite schist,,,MS002,73,Mount Saint Elias,Metamorphic,2715
Ksm?,Valdez Group -- Pelitic and quartzofeldspathic schist and gneiss,Late Cretaceous,"Reddish weathering, varibly banded, strongly schistose to granoblastic pelitic and quartzofeldspathic schist and gneiss. Typically a garnetiferous graphitic schist. Sedimentary clastic protolith.",,,MS002,80,Mount Saint Elias,Metamorphic,2715
Kvsm,Valdez Group -- Undifferentiated metavolcanic and metasedimentary rocks,Late Cretaceous,Largely interbedded mafic to intermediate metavolcanic rocks that were mainly volcaniclastic and metaclastic. Metasedimentary sequence locally includes metachert and thin lenses of marble.,,,YA002,81,Yakutat,Metamorphic,2715
Kpm,Pelitic and quartzofeldspathic schist and gneiss,Cretaceous,"Pelitic and quartzofeldspathic schist and gneiss with abundant sills, dikes, and small intrusive bodies of felsic granitic rocks",,,YA002,75,Yakutat,Metamorphic,2715,,
green,Schist,Cretaceous ?,Upper greenschist to amphibolite facies schist derived from metamorphism of interbedded graywacke and argillite of the Valdez Group,,,CV005,507,Cordova,Metamorphic,2715,,
pink,Transitional gneiss,Age not given,Upper amphibolite facies schist and gneiss interlayered at scale of meters to centimeters. Top of unit marked by appearance of quartofeldspathic segregations in metapelite and base of unit marked by loss of stratal continuity through development of gneissic segregations,,,CV005,508,Cordova,Metamorphic,2715,,
gray,Gneiss,Age not given,"Gray, banded quartzofeldspathic gneiss",,,CV005,509,Cordova,Metamorphic,2715,,
green,Schist,Cretaceous ?,Upper greenschist to amphibolite facies schist derived from metamorphism of interbedded graywacke and argillite of the Valdez Group,,,CV006,505,Cordova,Metamorphic,2715,,
pink,Transitional gneiss,Age not given,Upper amphibolite facies schist and gneiss interlayered at scale of meters to centimeters. Top of unit marked by appearance of quartofeldspathic segregations in metapelite and base of unit marked by loss of stratal continuity through development of gneissic segregations,,,CV006,506,Cordova,Metamorphic,2715,,
gray,Gneiss,Age not given,"Gray, banded quartzofeldspathic gneiss",,,CV006,507,Cordova,Metamorphic,2715,,
orange,Orthogneiss,Age not given,Metamorphosed plutonic rocks. Mostly Ti2 plutons within the gneissic core of the complex,,,CV006,509,Cordova,Metamorphic,2715,,
KJs,Marine sedimentary rocks,Cretaceous and Jurassic,"Thin- to medium-bedded argillite and graywacke, metamorphosed to hornfels near Klein Creek pluton. Part of informally designated Nutzotin Mountains sequence.","Buchia pelecypod, indicating Late Jurassic age",,MC002,13,McCarthy,Sedimentary,2820,,HFS
KJs,Marine sedimentary rocks,Early Cretaceous and Late Jurassic,"Upper Part: Argillite, graywacke, and mudstones, capped by sandstone, siltstone, and shale. Middle (major) Part: Argillite, siltstone, and graywacke, that alternate with a pebble to cobble conglomerate, pebbly graywacke, and an argillite. Lower Part: Argillite, minor siltstone, mudstone, graywacke, and impure limestone, and a localized pebble conglomerate. Locally known as the Nutzotin Mountains Sequence",Buchia indicate Late Jurassic and Early Cretaceous age,,NB002,118,Nabesna,Sedimentary,2820,,
KJs,Marine sedimentary rocks,Cretaceous and Jurassic,Thin- to medium-bedded argillite and graywacke. Graywacke is typically graded and rhythmically bedded. Metamorphosed to hornfels near Klein Creek pluton. Part of the informal Nutzotin Mountains sequence,,,MC003,325,McCarthy,Sedimentary,2820,,
KJs,Marine sedimentary rocks,Early Cretaceous and Late Jurassic,"Graded sedimentary rocks and conglomerate. Argillite grading to stiltstone to graywacke with interbedded massive, fine- to coarse-grained graywacke, and pebble and boulder conglomerate. Locally known as the Nutzotin Mountains Sequence.",,,NB004,412,Nabesna,Sedimentary,2820,,
Ja,Argillite,Late Jurassic,Dark shaly argillite in poorly defined beds with abundant thin beds and lenses of dense dark-gray iron-carbonate-bearing mudstone and siltstone. Minor interbeds of gray calcareous siltstone and sandstone.,,,NB004,413,Nabesna,Sedimentary,2820,,
KJs,Nutzotin Mountain Sequence,Lower Cretacous and Upper Jurassic,"Marine assemblage of dark argillite, gray siltstone, and graded beds of argillite-siltstone-graywacke. Contact metamorphism with the quartz diorite (Kg) has resulted in a banded calc-silicate hornfels",Sparse Buchia indicate a late Mesozoic age,,NB108,539,Nabesna,Sedimentary,2820,,
TKc,Conglomerate and sandstone,Tertiary and Cretaceous,"Green-gray to brown-gray pebble-to-boulder conglomerate, conglomeritic sandstone, and coarse-grained sandstone",,,NB002,147,Nabesna,Sedimentary,2824,,
Kys,Yakutat Group -- flysch facies,Cretaceous and Jurassic(?),"Yakutat Group is a heterogeneous assemblage including clastic sedimentary rocks, altered volcanic rocks, chert, carbonate, and granitic rocks. Two major subdivisions that are commonly structurally juxtaposed, a flysch facies and a melange facies. Flysch facies is dominatly dense, hard, poorly sorted gray to brown feldspathic to lithofeldspathic sandstone (graywacke), pebble-cobble conglomerate, and shale-chip conglomerate in thick channel deposits or rhythmically interbedded and graded with gray to black siltstone, argillite, or slate.",,,BG002,160,Bering Glacier,Sedimentary,2841,,
Kys,Yakutat Group -- flysch facies,Cretaceous and Jurassic(?),"Yakutat Group is a heterogeneous assemblage including clastic sedimentary rocks, altered volcanic rocks, chert, carbonate, and granitic rocks. Two major subdivisions that are commonly structurally juxtaposed, a flysch facies and a melange facies. Flysch facies is dominatly dense, hard, poorly sorted gray to brown feldspathic to lithofeldspathic sandstone (graywacke), pebble-cobble conglomerate, and shale-chip conglomerate in thick channel deposits or rhythmically interbedded and graded with gray to black siltstone, argillite, or slate.",,,MS002,45,Mount Saint Elias,Sedimentary,2841
Kys?,Yakutat Group -- flysch facies(?),Cretaceous and Jurassic(?),"Yakutat Group is a heterogeneous assemblage including clastic sedimentary rocks, altered volcanic rocks, chert, carbonate, and granitic rocks. Two major subdivisions that are commonly structurally juxtaposed, a flysch facies and a melange facies. This unit is predominatly dark-gray weathering clastic sedimentary rocks (siltstone) at Haydon Peak. Consists of 30 to 70 percent dark-gray, partly slaty carbonaceous and concertionary siltstone interbedded with thin beds and laminae of fine-grained, banded, sandstone and lesser olive-gray to dark-gray partly carbonaceous sanstone, pebble conglomerate having a dark silty matrix, green basaltic tuff, and light-gray tuffaceous sandstone. Intertongues and is gradational with lower part of Kulthieth Formation. Questionably part of Yakutat Group flysch facies, consisting of dominatly dense, hard, poorly sorted gray to brown feldspathic to lithofeldspathic sandstone (graywacke), pebble-cobble conglomerate, and shale-chip conglomerate in thick channel deposits or rhythmically interbedded and graded with gray to black siltstone, argillite, or slate.",Contains very sparse warm water molluscan fauna and abundant carbonized sub-tropical plant remains.,,MS002,46,Mount Saint Elias,Sedimentary,2841
Kys,Yakutat Group -- flysch facies,Cretaceous and Jurassic(?),"Yakutat Group is a heterogeneous assemblage including clastic sedimentary rocks, altered volcanic rocks, chert, carbonate, and granitic rocks. Two major subdivisions that are commonly structurally juxtaposed, a flysch facies and a melange facies. Flysch facies is dominatly dense, hard, poorly sorted gray to brown feldspathic to lithofeldspathic sandstone (graywacke), pebble-cobble conglomerate, and shale-chip conglomerate in thick channel deposits or rhythmically interbedded and graded with gray to black siltstone, argillite, or slate.",,,YA002,45,Yakutat,Sedimentary,2841
Kgd,Granodiorite -- Wrangellia Terrane,Cretaceous (?),Granodiorite pluton,,,GU002,136,Gulkana,Igneous,2900
hbqd,Hornblende-biotite quartz diorite; Peninsular Terrane,Jurassic or Cretaceous,Hornblende-biotite quartz diorite,,,GU002,173,Gulkana,Igneous,2900
hbqm,Hornblende-biotite quartz monzonite; Peninsular Terrane,Jurassic or Cretaceous,Hornblende-biotite quartz monzonite,,,GU002,174,Gulkana,Igneous,2900
hbgd,Hornblende-biotite granodiorite; Peninsular Terrane,Jurassic or Cretaceous,Hornblende-biotite granodiorite,,,GU002,175,Gulkana,Igneous,2900
Kyx,Yakutat Group -- melange facies,Cretaceous and Jurassic(?),"Yakutat Group is a heterogeneous assemblage including clastic sedimentary rocks, altered volcanic rocks, chert, carbonate, and granitic rocks. Two major subdivisions that are commonly structurally juxtaposed, a flysch facies and a melange facies. Melange facies is characteristically composed of blocks of competetn rocks of heterogeneous lithology as mush as several kilometers in size enclosed in a pervasively sheared matrix of drak-gray to black pelite, cherty pelite or tuffaceous pellite. Melange blocks are predominatly greenstone, oolitic limestone,marble, granitic plutonic rocks, chert, and graywacke.",,,MS002,49,Mount Saint Elias,Tectonite,2950
Kyx,Yakutat Group -- melange facies,Cretaceous and Jurassic(?),"Yakutat Group is a heterogeneous assemblage including clastic sedimentary rocks, altered volcanic rocks, chert, carbonate, and granitic rocks. Two major subdivisions that are commonly structurally juxtaposed, a flysch facies and a melange facies. Melange facies is characteristically composed of blocks of competetn rocks of heterogeneous lithology as mush as several kilometers in size enclosed in a pervasively sheared matrix of drak-gray to black pelite, cherty pelite or tuffaceous pellite. Melange blocks are predominatly greenstone, oolitic limestone,marble, granitic plutonic rocks, chert, and graywacke.",,,YA002,49,Yakutat,Tectonite,2950
s,Sandstone,Age not given,Larger lenticular bodies to 300m thick of massive laumonite-rich lithofeldspathic to feldspatholitihic sandstone mainly within the flysch facies. Probably represent deep sea channel fills with andesitic volcanic detritus dominant in the lithic component,,,YA002,53,Yakutat,Sedimentary,2951
c,Conglomerate,Age not given,Larger lenses and beds of well rounded and sorted pebble and cobble conglomerate to 200m thick that are locally developed within both the flysch and melange facies. Includes abundant angular blocks of gray oolitic limestone containing chert nodules in Kys unit at Russell Fiord near Hidden Glacier and olistostrome deposits exhibiting soft-sediment deformation in Kyx unit.,,,YA002,47,Yakutat,Sedimentary,2952
g,Greenstone,Age not given,"Larger greenstone masses within the melange facies of the Yakutat Group, generally massive and structureless but locally with faint pillow forms and agglomeratic texture. Commonly with epidote-rich pods and stringers and cut by diorite dikes. Associated with limestone and marble and pods of radiolarian ribbon chert. Marble may be Late Triassic age based on poorly preserved fossles near Russell Fiord. Interpreted as allochthonous blocks in the melange.",,,YA002,55,Yakutat,Metamorphic,2953
d,Tonalite,Jurassic,"Large bodies of foliate, fine- to medium-grained hornblende biotite tonalite associated with meta-greenstones. Interpreted as allochthonous blocks in the melange.",,K-Ar ages ranging from 146-178 m.y.,YA002,51,Yakutat,Igneous,2954
Kyb,Metamorphic rocks of the Brabazon Range,Cretaceous(?),"Mainly amphibolite facies rocks more than 1,000 -m-thick. Grades over narrow interval into zeolite- and prehnite-pumpellyite-grade rocks of the Yakutat Group. Protolith mainly graywacke-carbonaceous pelite sequence recrystallized to quartzofeldspathic schist.",,,YA002,59,Yakutat,Metamorphic,2980
Kym,Schist of Nunatak Fiord -- schist,Creatceous(?),"Typically fine- to medium-grained, semigranoblastic quartzofeldspathic schist.",,,MS002,61,Mount Saint Elias,Metamorphic,2981
Kym,Schist of Nunatak Fiord -- schist,Creatceous(?),"Typically fine- to medium-grained, semigranoblastic quartzofeldspathic schist.",,,YA002,61,Yakutat,Metamorphic,2981
Kyn,Schist of Nunatak Fiord -- Amphibolite-diorite complex at the Nunatak,Creatceous(?),High-grade amphibolite-diorite complex characterized by segregation and injection gneisses. Probable metamorphosed equivalent of Yakutat Group flysch facies.,,"Discordant K-Ar biotite-hornblende pair yielded 30 and 47 Ma, respectively.",YA002,57,Yakutat,Metamorphic,2981
Kyvm,Schist of Nunatak Fiord -- Metavolcanic rocks of Novatak Glacier area,Creatceous(?),"Predominantly massive porphyritic mafic flow rocks interbedded with thinly laminated green to light-gray metatuff. Metamorphosed to fine-grained, schistose, partly segregated epidote-amphibolite and amphibolite-facies assemblages.",,,YA002,63,Yakutat,Metamorphic,2981
Kyxm,Schist of Nunatak Fiord -- Schist of Novatak Glacier area,Creatceous(?),"Lithologically diverse sequence of metasediementary and metavolcanic rocks. Mainly thin-bedded metapelite, tuffaceous metapelite, pelitic schist, and quartzofeldspathic schist with subordinate stretched pebble conglomerate, metachert, gray-weathering marble, and thinly laminated tuffaceous greenschist.",,K-Ar recrystallization age of 65 Ma,YA002,65,Yakutat,Metamorphic,2981
Js,Undivided Jurassic marine sedimentary rocks,Jurassic,"Lower parts of the Matanuska-Wrangell terrane; subdivided into Lubbe Creek Formation: spiculite and minor coquina; Nizina Mountain Formation: graywacke; Root Glacier Formation: mudstone, siltstone, and subordinate sandstone, shale, and conglomerate. Broadly correlate with Jurassic rocks in Valdez Quad and Talkeetna Mtns",'Abundant fossils' indicate an age span from Pliensbachian to Kimmeridgian,,MC002,11,McCarthy,Sedimentary,3000
Jk,Kotsina Conglomerate,Middle or Late Jurassic?,"Well-indurated massive to very thick-bedded cobble- and pebble-conglomerate, with some bouldery strata. Olive-gray lithic and feldspathic sandstone, siltstone, and carbonaceous shale are interbedded in many places and increase in proportion west of Long Glacier.",Plant scraps,K-Ar age on biotite from a clast of 161 Ma and on hornblende from cross-cutting dike of 145 Ma,VA002,3110,Valdez,Sedimentary,3110
Jk,Kotsina Conglomerate,Late and Middle Jurassic,Thin- to thick-bedded conglomerate with locally derived pebbles and cobbles and subordinate sandstone and shale. Extends into Valdez Quad. Correlates to rocks in Talkeetna Mtns,,'Isotopic age' indicates an age span from late Jurassic to Middle to Late Jurassic,MC002,10,McCarthy,Sedimentary,3110
JTrc,"Marine clastic and carbonate rocks, undivided",Late or Middle Jurassic to Late Triassic,"Wrangellia terrane, Consists of Kotsina Conglomerate (Middle or Late Jurassic), lower part of the McCarthy Formation (Late Triassic), and the Chitistone and Nizina Limestones (Late Triassic)",,,VA007,34,Valdez,Sedimentary,3110
Jk,Kotsina Conglomerate,"Early Cretaceous and Late Jurassic, Berriasian, Thithonian, and Kimmeridgian","Forming bold, dark greenish gray, craggy outcrops, rocks consist of well-indurated massive cobble and pebble conglomerate, minor boulder conglomerate, with some arenite sandstone and siltstone interbeds. Conglomerate clasts derived from Triassic limestones, Nikolai Greenstone, and the Skolai Group. Unit reflects local accelerated uplift and erosion concomitant with the Late Jurassic / Early Cretaceous regional orogeny",,Isotopic age determined with a conglomerate clast and cross-cutting dike from the nearby Valdez quad yielded ages of 142 +/- 5 and 157 +/- my,MC100,114,McCarthy,Sedimentary,3110
Jtk,Talkeetna Formation,Early Jurassic,"Marine and non-marine andesitic and basaltic tuff, tuff breccia, and volcanogenic sedimentary rocks. Small, isolated bodies of light- to dark-gray unfossiliferous saccharoidal limestone may be parts of the units in the Valdez quadrangle.",Mollusks and brachiopods,,VA002,3250,Valdez,Igneous,3250
Jtrd,Rhyodacite flows; Talkeetna Formation,Early Jurassic,Rhyodacite flows with minor sandstones and lesser dacite flows,,,GU002,177,Gulkana,Sedimentary,3250
Jta,Hornblende andesite flows; Talkeetna Formation,Early Jurassic,Hornblende andesite flows,,,GU002,178,Gulkana,Igneous,3250
Jts,"Talkeetna Formation, sandstone",Early Jurassic,Sandstone with sparse volcaniclastic rocks,,,GU002,179,Gulkana,Sedimentary,3250
Jum,Ultramafic rocks,Early Jurassic or older,"Dunite, harzburgitic dunite, wehrlite, websterite, and clinopyroxenite comprise the Tonsina ultramafic complex. The rocks are folded but not intensely sheared or serpentinized.",,,VA002,3345,Valdez,Igneous,3340
Ju,Ultramafic rocks,Jurassic?,"Serpentized pyroxenite? Occurs within mafic plutonic complex (unit Jmp), generally localized in strongly sheared zones. Many areas of unit are too small to map.",,,VA002,3347,Valdez,Igneous,3340
Jlg,Layered quartz gabbro,Jurassic,"Conspicously layered, hypiodiomorphic-granular textured quartz gabbro. Layers enriched in clinopyroxene or in plagioclase and quartz give unit its prominent banded appearance. Prehnite-pumpellyite metamorphosed, little deformed and dips quite uniformly northward.",,"K-Ar age on pyroxene of 185 +/- 19 Ma is highly suspect, however matches ages on Afognak Pluton, the pluton of the Barren Islands and reputed ages on small dioritic plutons near Seldovia.",VA002,3340,Valdez,Igneous,5245
Jgr,Biotite-epidote granite,Middle Jurassic,Irregularily shaped small stocks of pink-weathering medium-grained granite. Green biotite and granular to coarse-grained epidote are constant accessories,,,VA002,3401,Valdez,Igneous,3401
Jgd,Biotite-hornblende granodiorite,Middle Jurassic,Irregularily shaped small stocks of pink-weathering medium-grained granite. Green biotite is a constant accessory; hornblende and epidote are less abundant and are not present in all samples.,,,VA002,591,Valdez,Igneous,3402
Jgd,Granodiorite to quartz diorite,Juarssic?,Weakly foliated to foliated granodiorite to quartz diorite. Possibly equivalent to rocks of the Chitina Valley batholith Granite Range plutonic suite in the northern Chugach Mountians,,,BG002,171,Bering Glacier,Igneous,3402
Jc,Chitina Valley batholith,Late Jurassic,"Weakly to strongly foliated compositionally diverse plutonic rocks. Dominant lithology is fine-to medium-grained hypiomorphic granular quartz monzodiorite, but quartz diorite, tonalite, and granodiorite are nearly as abundant.",,"K-Ar hornblende ages range from 147 +/- 7 to 157 +/- 8 Ma, biotite ages are 134 and 144 +/- 7 Ma; one mineral pair is slightly discordant.",VA002,3403,Valdez,Igneous,3403
Jc,Chitina Valley Batholith,Late Jurassic,"Strongly foliated Tonalite, granodiorite, and rocks rangong from granite to quartz diorite. No known volcanic equivalents, however, coextensive with batholithic rocks of Bering Glacier Quad. Also correlates with granitic rocks of the E Valdez Quad",,Hornblende radiometric age range of 138 to 146+4 m.y.,MC002,9,McCarthy,Igneous,3403
JTrq,Hornblende quartz-diorite,Jurassic and Triassic,"Part of ""diorite complex."" Medium- to coarse-grained hornblende quartz-diorite, hornblende-biotite quartz diorite, and subordinate leucocratic quartz diorite",,K-Ar dates of Middle Jurassic for plutonic rocks and Late Triassic for metamorphic rocks,NB002,144,Nabesna,Igneous,3403
Jt,"Tonalite, diorite, and leucodiorite of Chitina Valley batholith",Late Jurassic,"Tonalite, diorite, and leucodiorite of Chitina Valley batholith. Mainly diorite, leucodiorite, and tonalite, but locally includes gabbro, especially near contacts. Generally medium-grained but varies from fine to coarse and pegmatitic. Ranges from weakly to non-foliated in interior of plutons to strongly foliated and locally mylonitic towards contacts.",,,BG002,170,Bering Glacier,Igneous,3403
Jc,Chitina Valley batholith,Late Jurassic,"Wrangellia terrane, Chitina Valley batholith",,,VA007,32,Valdez,Igneous,3403
Jc,Chitina Valley batholith,"Early Cretaceous and Late Jurassic, Berriasian and Thithonian","Poorly foliated, fine to medium-grained hypidiomorphic-granular granodiorite with subordinate granitic and dioritic phases. Rocks cut locally by Tertiary hypabyssal rocks. Sporadic vienlets consist of quartz or calcite, prehnite, and rare stilbite. The hydrothermally altered zones are characterized by seicite, pyrite, and rare coppers. Dikes are porphyritic. The batholith is synchronous with early stages of a regionally extensive orogeny",,"K-Ar dates (on hornblende) in granodiorites yielded the following ages: 134 +/- 7, 142 +/- 4, 145 +/- 4, 142 +/- 4, and 141 +/- 5 my",MC100,113,McCarthy,Igneous,3403
Jc,Chitna Valley batholith,Late Jurassic,"Chiefly quartz monzodiorite, but compositionally diverse, ranging from granite to diorite. Generally foliated and locally gniessic, especially in plutons enclosed in the Strelna Metamorphics",,K-Ar ages range from 157 to 138 Ma with foliated phases yielding datas as young as 122 Ma,BG004,317,Bering Glacier,Igneous,3403
Jc,Chitina valley batholith - Wrangellia Terrane,Late Jurassic,"Chiefly quartz monzodiorite, but compositionally diverse ranging from granite to diorite. Generally foliated and locally gneissic, especially in plutons enclosed in the Strelna Metamorphics (PPasm)",,K-Ar dates indicate plutonic ages of 138-157 Ma; ages and foliated phases are as young as 122 Ma,GU003,323,Gulkana,Igneous,3403
Jmp,Mafic plutonic complex,Early or Middle Jurassic,"Consists dominantly of layered hornblende-pyroxene gabbro and leucogabbro, with minor ultramafic, dioritic, and tonalitic rocks. The southern margin of complex is a major fault zone; cataclastic modification of mineral layering in the complex near the fault zone is severe; in many places the complex is thoroughly sheared and includes boudins of country rock. Mylonitic layering is also conspicious along a a major east-west fault within the complex.",,K-Ar ages on low-potassium hornblende and chloritized biotite range from 153 to 171 Ma.,VA002,3405,Valdez,Igneous,3405
Jgl,Hornblende gabbro and leucogabbro,Early Jurassic or older,"Layered gabbro and leucogabbro; layered gabbro is dominantly hornblende gabbro; hornblende-augite gabbro is common, however, with the hornblende replacing or molded upon the augite; and layers and lenses of hornblendite occur at several places. Mafic part of the Tonsina Complex (now shown on Winklers map as Jtg).",,"K-Ar ages on hornblende of 419 +/-21, 188 +/-8, and 171 +/- 5 Ma; the older age is considered suspect.",VA002,3540,Valdez,Igneous,3540
shgb,Schistose hornblende gabbro; Metamorphic Complex of Gulkana River,Late Jurassic or older,Schistose hornblende gabbro,,,GU002,164,Gulkana,Metamorphic,3540
scgb,Schistose clinopyroxene gabbro; Metamorphic Complex of Gulkana River,Late Jurassic or older,Schistose clinopyroxene gabbro,,,GU002,165,Gulkana,Metamorphic,3545
Klc,Schist of Liberty Creek,mid-Cretaceous? or Jurassic??,"Well-foliated, multiply-deformed greenschist and transitional blueschist facies mafic metavolcanic and metasedimentary rocks. Schistocity is well-developed although primary sedimentary or volcaniclastic features are retained locally. There are no marker strata and units do not persist laterally.",,,VA002,3610,Valdez,Metamorphic,3610
Jgb,Greenschist and transitional blueschist,Jurassic,"Chiefly intercalated greenschist and blueschist, but includes lawsonite, muscovite, or actinolite schist, carbonaceous schist, highly siliceous rocks containing stilpnomelane, and foliated calcareous rocks. Similar to Raspberry, Seldovia, and Knik River schist units.",,"K-Ar ages on crossite and muscovite range from 152 to 175 Ma, thought to be metamorphic ages.",VA002,572,Valdez,Metamorphic,3610
JTrm,McCarthy Formation -- lower member,Early Jurassic? and Late Triassic (Norian),"Marine limestone, shale, and chert. Lower member consists of interbedded finely-laminated, dark-gray, impure limestone, subordinate fissile shale, and minor chert.",Monotis and both calcareous and silicieous microfossils.,Minimum age from intruding granodiorite of 144 Ma,VA002,3821,Valdez,Sedimentary,3820,,
JTrm,McCarthy Formation,Early Jurassic and Late Triassic,"Formerly named McCarthy Shales. Upper: thin bedded, fine-grained spiculite, impure chert, impure limestone, and shale; Lower: thin-bedded impure limestone (wackestone), calcareous carbonaceous shale, and impure, locally spiculitic, chert. Temporal, but not lithologic, equivalents in Talkeetna Formation in Talkeetna Mtns. Monotis-bearing Upper Triassic rocks in Nabesna Quad probable correlative",Upper: 'paleontological evidence' indicates an age span from Hettangian to Pliensbachian Lower: Monotis pelecypods and other 'fossils' indicate Norian age,,MC002,8,McCarthy,Sedimentary,3820,,
JTrm,McCarthy Formation,Early Jurassic and Late Triassic,"Named by MacKevett (1963) for exposures in the Wrangell Mountains. Exposed in Bering Glacier D-2 quadrangle only along the south side of the Chitina River where it consists of a few hundred meters of consists mostly of dark-gray to black, calcareous carbonaceous shale and subordinate thin-bedded limestone containing numerous calcite veinlets. Formation contains minor asymmetric, north-verging tightly-appressed folds and is cut by numerous south-dipping faults roughly parallel to the Chitina Valley fault. Paleontologic evidence (cited in MacKevett, 1970a, b; 1971, p. 15, 29) documents Early Jurassic ages that range from Hettangian to Pliensbachian Stages; possibly the unfossiliferous lowermost parts of the unit are as old as latest Triassic.","Paleontologic evidence (cited in MacKevett, 1970a, b; 1971, p. 15, 29) documents Early Jurassic ages that range from Hettangian to Pliensbachian Stages",,BG002,172,Bering Glacier,Sedimentary,3820,,
JTrml,McCarthy Formation - Lower member,"Early Jurassic and Late Triassic, Norian","Impure limestone (wackestone and subordinate lime mudstone) intercalated with shale (dark gray, fissile, finely laminated calcareous carbonaceous containing abundant microfossils) and minor chert (gray/brownish-black microcrystalline silica). Limestone has a localized hackly fracture pattern. Member has been cut by the Chitina batholith and Tertiary hypabyssal rocks. Some rocks are weakly metamorphosed, recrystallized and poorly foliated",Widespread pelecypods of the genus Monotis indicate the late Norian Stage of the Late Triassic found in the lower parts of the member,,MC100,115,McCarthy,Sedimentary,3820,,
Trl,Limestone,Late Triassic,"Upper Part: thin-bedded, fine-grained limestone, interbedded with thin beds of argillite and carbonaceous shale. Minor beds of calcareous sandstone and grit Lower Part: fine-grained, massive limestone with chert lenses",Monotis subcircularis; hydrozoa (Lovcenipora?); Spondylspira,,NB002,119,Nabesna,Sedimentary,4029,,
Trtl,Thin-bedded limestone,Late Triassic,Dark-gray fine-grained limestone thick with thin interbeds of dark carbonaceous shale.,,,NB004,414,Nabesna,Sedimentary,4029,,
Trml,Massive limestone,Late Triassic,Massive limestone with lenses and modules of black and gray chert and irregular patchworks of disseminated fine-grained quartz. Commonly strongly brecciated and veined by coarsely crystaline calcite.,,,NB004,415,Nabesna,Sedimentary,4029,,
Trtl,Thin-bedded limestone,Late Triassic,"Fine-grained limestone in beds (<2 m) interbedded with carbonaceous shale and argillite. Chiefly micrite and biomicrite, locally dolomitized. Contact metamorphism with quartz diorite produced a garnet-rich calc-silicate skarn locally containing disseminated sulfide minerals",Age based on fossil evidence in Nabesna C-5,,NB108,540,Nabesna,Sedimentary,4029,,
Trml,Massive limestone,Late Triassic,"Massive fine-grained limestone. Locally abundant lenses of chert and irregular patchwork of siliceous material. Chiefly micrite and microsparite, locally dolomitized. Contact metamorphism with quartz diorite produced a garnet-rich calc-silicate skarn locally containing disseminated sulfide minerals",Age based on fossil evidence in Nabesna C-5,,NB108,541,Nabesna,Sedimentary,4029,,
Trl,Chitistone and Nizina Limestones,Late Triassic (Karnian and Norian),"Light- to medium-gray limestone of diverse textural varieties and include minor dolomite lower in the sequence and nodules and lenses of dark-gray chert high in the sequence. Lower thicker-bedded sequence is Chitistone Limestone, upper, thinner-bedded sequence is Nizina Limestone.",,,VA002,4030,Valdez,Sedimentary,4030,,
Trcn,Chritistone and Nizina Limestones,Late Triassic,"Both have marked lateral changes in thickness. Lowest Chitistine: dolomite algal-mat chips, stromatolites and evaporites. Upper Chitistine: diverse limestone including lime mudstones, wackestone, packstone, and grainstone. Nizina: diverse limestone with subordinate chert nodules, lenses,and coalescing masses. Probable correlatives of Triassic carbonate rocks in Nabesna Quad and south-central Alaska",Chitistone: Tropites indicate a Karnian age. Nizina: ammonites and pelecypods indicate an age span from Late Karnian to Middle Norian,,MC002,27,McCarthy,Sedimentary,4030,,
Trm,Marble,Late Triassic,"Fine- to medium-grained calcite-rich marble, locally dolomitic, sometimes schitose or banded. Contact-metamorphosed Chritistone and Nizina Limestones, near granitic plutons of the Chitina Valley batholith.",,,MC002,33,McCarthy,Metamorphic,4030,,HFS
Trn,Chitistone and Nizina Limestones,Late and Middle Triassic,"The limestone is medium- to thick-bedded, white to medium gray, and commonly emits fetid odors when freshly broken. Undifferentiated Chitistone and Nizina limestones occur locally along the south side of the Chitina River in the D-2 quadrangle and between the Chitina and Logan glaciers in the D-1 quadrangle. Maximum aggregate thickness of the two formations in these areas is about 250 meters and both formations are characterized by marked lateral changes in thickness. Local minor to major, north-verging isoclinal folds occur in the Chitistone or Nizina Limestones near the Chitina Valley fault system. Disconformably overlies the Nikolai Greenstone in Marble Canyon and probably grades upward into the McCarthy Formation. ","Unfossiliferous; in the McCarthy quadrangle to the north, diagnostic fossils indicate a Late Triassic age (MacKevett, 1978).",,BG002,180,Bering Glacier,Sedimentary,4030,,
Trnz,Nizina Limestone,"Late Triassic, Norian and Karnian","Rocks consist of thin-bedded limestone (shades of gray, fine-grained wackestone and lime mudstone with a hackly fracture) and abundant greenish-black chert in thin lenses. Unit has been cut by the Chitina batholith and Tertiary hypabyssal rocks","Sponge spicules, radiolarians, and comminuted shelly debris occur in the upper strata. Poorly preserved, fragmented pelecypods of the genus Halobia were found",,MC100,116,McCarthy,Sedimentary,4030,,
Trnzm,Nizina Limestone - Marble,"Late Triassic, Norian and Karnian",Generally consists of fine-grained granoblastic calcite with minor bands of diopside and epidote. Locallized into small masses that have been recrystallized near the Chitina Valley batholith,,,MC100,117,McCarthy,Metamorphic,4030,,HFS
Trc,Chitistone Limestone,"Late Triassic, Karnian","Medium to thick bedded lime mudstone (dark greenish gray, fine-grained and incipiently recrystallized), and less abundant wackestone. Limy dolomite and dolomitic limestone in lower strata reflecting sabkha facies. Widespread calcite veinlets, and poorly developed stylolites and chert nodules. Unit has been cut by the Chitina batholith and Tertiary hypabyssal rocks",Undiagnostic comminuted remains of echinoids and gastropods. Elsewhere the Chitistone is documented by the ammonite Tropites,,MC100,118,McCarthy,Sedimentary,4030,,
Trcm,Chitistone Limestone - Marble,"Late Triassic, Karnian","Small masses of marble and skarn near the granodiorite of the Chitina Valley batholith. Locally banded, the marble is fine to medium grained granoblastic calcite. The skarn consists mainly of diopside and has local pods and disseminations of pyrite, pyrrhotite, magnetite, and minor chalcopyrite near the marble-granodiorite contacts",,,MC100,119,McCarthy,Metamorphic,4030,,HFS
Trcn,Chitistone and Nizina Limestones,Late Triassic,Chiefly limestone and dolostone; minor chert and marble. Both units locally fossiliferous,"Abundant algal-mat chips and stromatolites,",,BG004,325,Bering Glacier,Sedimentary,4030,,
Trc,Conglomerate and shale,Middle Triassic,Intermixed conglomerate and carbonaceous shale and argillite. Conglomerate contains subangular to rounded clasts,Shale beds contain abundant Daonella of Middle Triassic age,,NB108,543,Nabesna,Sedimentary,4130,,
Trg,Gabbro,Late and (or) Middle Triassic,"Medium- to coarse-grained, subophitiic gabbro",,,MC002,28,McCarthy,Igneous,4320,,
Trg,Gabbro and diabase and gabbronorite dikes -- Wrangellia Terrane,Late Triassic (?),Clinopyroxene-hornblende gabbro and diabase and gabbronorite dikes,,,GU002,138,Gulkana,Igneous,4320,,
Trcg,Stocks and plugs -- Wrangellia Terrane,Late Triassic (?),Clinopyroxene-hornblende stocks and plugs,,,GU002,139,Gulkana,Igneous,4320,,
Trg,Gabbro,"Late Middle Triassic and Early Late Triassic, Karnian and Ladinian","Rock is dark green gray, fine to meduim grained, subophitic; interpreted as feeders and progenitors of Nikolai basaltic lavas. Having rare porphyritic phases, unit forms small plutons, dikes and sills cutting, predominantly, the Hasen Creek Formation with a few small dikes withing the Nikolai Greenstone. It is cut by Tertiary hypabyssal dikes and locally, calcite veinlets",,,MC100,120,McCarthy,Igneous,4320,,
JTrs,Quartz-feldspar schist and cataclastite,Jurassic and Triassic,"Part of ""diorite complex."" Quartz-feldspar schist and cataclastite",,K-Ar dates of Middle Jurassic for plutonic rocks and Late Triassic for metamorphic rocks,NB002,142,Nabesna,Igneous,4410,,
JTrg,Pink biotite-hornblende syenite-monzonite gneiss,Jurassic and Triassic,"Part of ""diorite complex."" Pink biotite-hornblende syenite -monzonite gneiss with thin layers of gray hornblende diorite gneiss, and minor dark biotite schist. Small syenite pegmatite dikes",,K-Ar dates of Middle Jurassic for plutonic rocks and Late Triassic for metamorphic rocks,NB002,145,Nabesna,Igneous,4415,,
Trn,Nikolai Greenstone,Middle and (or) Late Triassic,"Weakly metamorphosed, lightly altered tholeiitic basalt that is characteristically amygdaloidal and poorly bedded. Metamorphosed to prehnite-pumpellyite facies",,K-Ar whole-rock isochron of 112 +/- 11 Ma thought to indicate collosion of Wrangellia with North America,VA002,4420,Valdez,Igneous,4420,,
Trn,Nikolai Greenstone,Late and (or) Middle Triassic,"Dominently slightly porphyritic tholeiitic basalt sequence; basal sections include pillow basalt and intercalated argillite; basal sections elsewhere are volcanic conglomerate with dominent intermixed pahoehoe and aa, typically altered and locally metamorphosed to prehnite-pumpellyite from metamorphism. Occur sparingly in NE Bering Glacier Quad",Ladinian aged pelecypods and Karnian aged ammonites,,MC002,303,McCarthy,Igneous,4420,,
Trn,Nikolai Greenstone,Triassic,Subaerial porphyritic basalt flows interbedded with volcaniclastic rocks; basal sections include volcanic conglomerate-breccia with dominent intermixed pahoehoe and aa,,,NB002,120,Nabesna,Igneous,4420,,
Trn,Nikolai Greenstone,Late Triassic,Nikolai Greenstone,,,GU002,155,Gulkana,Sedimentary,4420,,
Trng,Nikolai Greenstone,Late and (or) Middle Triassic,"Dominantly thick flow units of slightly porphyritic tholeiitic basalt with medium-grained plagioclase (labradorite) and less abundant clinopyroxene phenocrysts in fine-grained intergranular groundmasses rich in plagioclase and clinopyroxene. Characteristically greenish black with light green to white amygdules; typically altered and locally metamorphosed to prehnite-pumpellyite facies assemblages. Named by Rohn (1900, p. 425) for extensive, mainly altered tholeiitic basalt sequence that occurs widely in the Wrangell Mountains and Chitina Valley area; at least 3,000 m in aggregate thickness. In the map area the unit is at 60 meters thick; the lower contact is faulted; overlain disconformably(?) by undifferentiated Chitistone and Nizina limestones (Upper Triassic) or unconformably by younger rocks. ",,,BG002,181,Bering Glacier,Igneous,4420,,
Trn,Nikolai Greenstone,Triassic,"Amygdaloidal tholeiitic basalt lava flows and minor associated volcaniclastic rocks. Pillow structures common along lower Ptarmigan Creek, but lavas are typically subaerial",,,MC003,327,McCarthy,Metamorphic,4420,,
Trn,Nikolai Greenstone,Late and (or) Middle Triassic,Amygdaloidal basalt flows separated locally by volcaniclastic beds. Intermixed aa and pahoehoe flows with individual flow units.,,,NB004,416,Nabesna,Igneous,4420,,
Trn,Nikolai Greenstone,Late and (or) Middle Triassic),"Wrangellia terrane, Nikolai Greenstone",,,VA007,35,Valdez,Metamorphic,4420
Trn,Nikolai Greenstone,Upper and/or Middle Triassic,"Green amygdaloidal basalt flows, separated by locally thin volcaniclastic beds. Intermixed aa and pahoehoe flows. Rocks largely thermally metamorphosed to fine-grained assemblages of actinolite, epidote, and chlorite. Includes a number of Triassic gabbro sills and dikes",,,NB108,542,Nabesna,Igneous,4420
Trng,Nikolai Greenstone,"Late Middle Triassic and Early Late Triassic, Karnian and Ladinian","A voluminous undifferentiated tholeiitic basalt that attains a composite thickness of 3000 m. Unit is composed of very fine to fine grained flows which contain abundant amygdules and is partially porphyritic. It has been intruded by the Chitina Valley batholith, Tertiary hypabyssal rocks, small gabbro feeder dikes, and veinlets of quartz and calcite. Parts near the batholith have been thermally metamorphosed and contain hornblende. It is believed to be part of an extensive upper mantle lava field produced during tensional tectonics",,,MC100,121,McCarthy,Igneous,4420
GG,Gabbroic phaciods in McHugh Complex,Jurassic and Late Triassic(?),Strongly altered gabbroic phacoids that are tectonic inclusions in the McHugh Complex,,,VA004,4890,Valdez,Metamorphic,4890
ds,Dadina schist,Late Paleozoic (?) or older,"Coarse quartz-biotite schist, altered and cataclastic meta-andesite, over lain(?) by amphibolite schist, mica-schist, and minor meta-limestone. Intruded by unmetamorphosed coarse-grained quartz diorite dikes. Also includes sheared meta-gabbro. Dadina Schist (Mendenhall, 1905). Correlated with Klutina of Schrader (1900) or with Strelna Formation of Moffit and Mertie (1923) [probably NOT Strelna].",,,GU002,172,Gulkana,Metamorphic,5204
Kag,Haley Creek terrane -- metaplutonic rocks,mid-Cretaceous?,"Metamorphosed complexly deformed and tectonically mixed plutonic and sedimentary rocks. Metaplutonic rocks are most abundant in southern part of the terrane and are compositionally diverse and weakly to strongly foliated. Although diorite and granodiorite are most abundant lithologies, compositions range from trondjhemite to hornblende gabbro and hornblendite. Amphibolite is is widespread within the metaplutonic rocks.",,K-Ar ages on hornblende range from 122 to 148 Ma. A muscovite age is 133 +/- 4 Ma,VA002,2721,Valdez,Metamorphic,5245
Jag,Uranatina River metaplutonic unit,Jurassic and Middle Pennsylvanian,"Portion of tectonic inclusion 10 by 15 km in McHugh Complex consisting of layered quartz gabbro, amphibolite, and orthogneiss. This unit consists of compositionally banded very mafic amphibolite to hornblende-biotie dioritic and quartz dioritic gneiss. Contains lenses of pyroxenite as much as 2 m across. Foliation of the rocks is swirled or tightly folded in many places and large hornblende or hornblende-plagioclase pods have grown in the hinges of many folds. Most of unit is likely of Jurassic age but is known to contain at least locally Middle Pennsylvanian metagranodiorite.",,"Low-potassium hornblende yielded K-Ar age of 267 +/- 8 Ma (mid-Permian), thought to approximate time of metamorphism.",VA002,5245,Valdez,Metamorphic,5245
sqm,Schistose quartz monzonite; Metamorphic Complex of Gulkana River,Late Jurassic or older,Schistose quartz monzonite,,,GU002,160,Gulkana,Metamorphic,5245
sqd,Schistose quartz diorite; Metamorphic Complex of Gulkana River,Late Jurassic or older,Schistose quartz diorite,,,GU002,161,Gulkana,Metamorphic,5245
sgd,Schistose granodiorite; Metamorphic Complex of Gulkana River,Late Jurassic or older,Schistose granodiorite,,,GU002,162,Gulkana,Metamorphic,5245
shd,Schistose hornblende diorite; Metamorphic Complex of Gulkana River,Late Jurassic or older,Schistose hornblende diorite,,,GU002,163,Gulkana,Metamorphic,5245
ag,Amphibolite gneiss; Metamorphic Complex of Gulkana River,Late Jurassic or older,Amphibolite gneiss,,,GU002,166,Gulkana,Metamorphic,5245
Pzs,Skolai Group -- greenstone unit,"Late Paleozoic, Middle Pennsylvanian to Early Permian","Diverse Upper Paleozoic volcanic, volcaniclastic, and marine sedimentary rocks. Unit consists largely of two lithologies, map unit Pzs is dark, greenish-gray poorly bedded greenstone, characterized by prehnite-pumpellyite mineral assemblages, locally retaining relict pillows and map unit Pzm is subordinate light- or medium-gray and buff calcareous rocks, mostly recrystallized to marble but containing scanty fragments of fossils, interbedded with minor dark-gray calcareous siltstone and shale.",,,VA002,5631,Valdez,Metamorphic,5325
Pzg,Gabbro and leucogabbro,"Late Paleozoic, Permian to Pennsylvanian","Gabbroic rocks rocks consisting of sills, dikes, and discordant plutons. Medium- to coarse-grained, massive to foliated, altered gabbro, leucogabbro, and minor diorite. Coextensive with layered gabbro in the McCarthy quadrangle.",,"K-Ar age on actinolitic amphibole of 246 +/- 12 Ma, thought to be minimum age, may be partially reset by intrusion of nearby Late Jurassic hornblende granodiorite pluton.",VA002,5460,Valdez,Igneous,5460
Pgo,Gabbro and Orthogneiss,Pennsylvanian,"Interlayered quartz monzonite gneiss, monzonite gneiss, and associated altered and foliated gabbro, with minor dioritic phases. Gabbro and orthogneiss extend into Valdez Quad.",,Biotite of the gneiss yields a radiometric date of 271+11 m.y.,MC002,5,McCarthy,Igneous,5460
Pzg,Gabbro and Anorthosite,Late Paleozoic (?),Medium-grained leucocratic gabbro and hornblende gabbro mixed with altered anorthosite,,,NB002,166,Nabesna,Igneous,5470
Pzum,Ultramafic rocks,Late Paleozoic (?),Serpentinized peridotite (lherzolite) and dunite,,,NB002,167,Nabesna,Igneous,5470
Pu,Ultramafic rocks,Pennsylvanian,"Serpentinized alpine-type, intensly sheared, ultramafic rock; includes some partly serpentinized gabbro. Correlates with ultramafic rocks of Nabesna Quad.",,,MC002,7,McCarthy,Igneous,5470
mha,Metamorphosed hornblende andesite; Metamorphic Complex of Gulkana River,Late Paleozoic (?) or older,Metamorphosed hornblende andesite,,,GU002,167,Gulkana,Metamorphic,5550
PPasm,Metamorphosed Skolai Group,Early Permian and Pennsylvanian,"Greenschist- to amphibolite-facies metamorphic rocks, mainly schist, phyllite, amphibolite, and marble. Corresponds to the Mississippian Strelna Formation.",'Fossil collections' indicate an Early Permian age.,,MC002,19,McCarthy,Metamorphic,5625
PPs,Skolai Group,Early Permian and Pennsylvanian,"Wrangellia terrane, Skolai Group",,,VA007,40,Valdez,Metamorphic,5625
Ps,Slana Spur Formation,Early Permian,"Part of Mankomen Group. Volcanic siltstone, sandstone, and conglomerate with subordinate lapilli tuff, volcanic breccia and impure biomicritic limestone. Equivalent to parts of the Cache Creek Group and the Skolai Group",,,NB002,124,Nabesna,Sedimentary,5630
PPs,Slana Spur Formation,Middle and Late Pennsylvanian and Early Permian,Slana Spur Formation,,,GU002,156,Gulkana,Sedimentary,5630
Pzvc,Volcanic rocks,Late Paleozoic,"Dark-gray thin-bedded fine- to medium-grained volcanic sandstone, cherty argillite, quartzite, and tuff. Weakly metamorphosed (greenschist facies). May be equivalent to Tetlna Volcanics (PPt) or Devonian terrane (Dp).",,,NB002,151,Nabesna,Metamorphic,5635
Pzv,Volcanic rocks,Late (?) Paleozoic,"Dark-greenish-gray fine-grained to weakly porphyritic andesite and basalt flows with abundant reddish jasperoid breccia, and minor intebeds of red and green cherty mudstone. Weakly metamorphosed (greenschist facies). May be equivalent to Tetlna Volcanics (PPt) or Devonian terrane (Dp).",,,NB002,150,Nabesna,Metamorphic,5636
mcb,Metamorphosed clinopyroxene basalt; Metamorphic Complex of Gulkana River,Late Paleozoic (?) or older,Metamorphosed clinopyroxene basalt,,,GU002,170,Gulkana,Metamorphic,5641
am,Amphibolite; Metamorphic Complex of Gulkana River,Late Paleozoic (?) or older,Amphibolite,,,GU002,171,Gulkana,Metamorphic,5680
Ph,Hasen Creek Formation,Early Permian,"Argillite, shale, sandstone, chert, limestone, and minor conglomerate. Locally thermally metamorphosed near Jurassic plutons.",,,MC002,20,McCarthy,Sedimentary,5750
Ph,Hasen Creek Formation,Permian,"Marine argillite and minor sandstone and chert, locally fossiliferous. May include some volcaniclastic rocks. Abundant Triassic gabbro sills. Correlative with the Mankomen Group in Nabesna quadrangle",,,MC003,311,McCarthy,Sedimentary,5750
Ph,Skolai Group - Hasen Creek Formation,"Early Permian, Guadalupian, Leonardian, and Wolfcampian","Weakly metamorphosed, diverse, thin bedded argillite, with less abundant lithic graywacke, conglomerate, shale, chert, schist, marble, and limestone (carbonates are unit Phl). The argillite and shale are shades of gray, yellowish brown, fine grained, silica rich rocks. The graywacke and conglomerate are both variegated, have calcite rich matrices and multicolored clasts. The formation has been cut by Triassic gabbro, the Chitina Valley batholith, and Tertiary hypabyssal rocks. It is believed to be the remnants of a late Paleozoic island arc. Believed to correlate with Eagle Creek Formation in the Alaska Range",,,MC100,122,McCarthy,Sedimentary,5750
Phl,Skolai Group - Limestone and marble,"Early Permian, Guadalupian, Leonardian, and Wolfcampian","The limestone predominantly occurs at the base of the section and sporadically ditributed limestone and marble elsewhere. Coarse-grained bioclastic grainstone with local conglomeratic facies (containing pebbles derived from the Station Creek and Hansen Creek Formations) and their metamorphosed equivalents, primarily recrystallized calcite.","Abundant crinoid columnals and lesser brachiopods, bryozoans, and gastropods. The multiple species of the brachiopod assemblage represents typical arctic Permian fauna of late Leonardian to early Guadalupian age",,MC100,123,McCarthy,Sedimentary,5750
Pl,Limestone of the Hasen Creek Formation,Early Permian,"Thin- to thick-bedded, fossiliferous, limestone. Includes Golden Horn Limestone Lentil. Correlates with the Eagle Creek Formation of the Mankomen Group in eastern Alaska Range in Nabesna Quad. Also correlates with Cache Creek Group of Yukon Territory.","Corals, crinoids, brachiopods, bryozoans,fusilinid indicate Early Permian (Wolfcampian)",,MC002,21,McCarthy,Sedimentary,5755
Pl,Limestone,Permian,Thin unit (10-30 m) of sand- and silt-rich limestone that appears to separate sedimentary rocks of the Hasen Creek Fm (Ph) from the underlying volcaniclastic rocks of the Station Creek Fm (PlPsc). Found in small block of Paleozoic and Mesozoic rocks north of Ptarmigan Lake,abundant crinoid and coral fragments,,MC003,324,McCarthy,Sedimentary,5755
Pel,Limestone,Early Permian,Part of Mankomen Group. Thin- to thick-bedded fossiliferous limestone occuring at the base of the Eagle Creek Formation. Base is a coarse-grained clastic limestone. Gabbroic dikes and sills. Equivalent to parts of the Cache Creek Group and the Skolai Group,,,NB002,123,Nabesna,Sedimentary,5756
Pm,Monzonitic-Granitic Complex,Early Permian and Pennsylvanian,"Medium-grained, equigranular granitic rocks with fine- to coarse-grained variants. Abundant granite and quartz monzonite and some quartz syenite, syenite, and monzonite, with border zones of quartz monzodiorite, monzodiorite, and gabbro. In both the Bering Glacier and McCarthy Quads. Correlates with Ahtell pluto of E Alaska Range (pluton has a K-Ar of 285 m.y.)",,Hornblende of monzonite and quartz monzonite gives age of 295+8 and 297+9 m.y..,MC002,6,McCarthy,Igneous,5870
Pam,"Monzonite, syenite, gabbro",Middle Pennsylvanian,"Massive to schistose, medium- to coarse-grained monzonite, syenite, gabbro, contains local inclusions of meta-andesite. Chiefly pink to gray-green monzonite and syenite, consisting of hornblende, K-spar, biotite, and plagioclase with local K-spar rich areas up to 8 cm diameter",,,BG002,220,Bering Glacier,Igneous,5870
Pag,Diorite and quartz diorite,middle Paleozoic(?) and older(?) (Pennsylvanian?),"Granite and syenite, medium- to coarse-grained, and schistose. Syenite chiefly schistose, gray-green hornblende-Kspar-biotite-plagioclase syenite. Local K-spar rich areas up to 8 cm diameter. Contains local inclusions of meta-andesite.",,,MS002,87,Mount Saint Elias,Igneous,5870
Pag,Diorite and quartz diorite,middle Paleozoic(?) and older(?) (Pennsylvanian?),"Granite and syenite, medium- to coarse-grained, and schistose. Syenite chiefly schistose, gray-green hornblende-Kspar-biotite-plagioclase syenite. Local K-spar rich areas up to 8 cm diameter. Contains local inclusions of meta-andesite.",,,YA002,87,Yakutat,Igneous,5870
PPf,Ahtell Pluton,Permian and Pennsylvanian,Fine-grained biotite granite,,,GU002,145,Gulkana,Igneous,5871
PPp,Ahtell Pluton,Permian and Pennsylvanian,Porphyritic hornblende granodiorite,,,GU002,146,Gulkana,Igneous,5871
PPg,Ahtell Pluton,Permian and Pennsylvanian,Biotite-hornblende granite and granodiorite,,,GU002,147,Gulkana,Igneous,5871
JTrd,Hornblende-rich diorite,Jurassic and Triassic,"Part of ""diorite complex."" Hornblende diorite with subordinate hornblende granodiorite, hornblende-biotite quartz monzonite, biotite quartz monzonite, hornblende diorite gneiss, clinopyroxene-hornblende gneiss, hypersthene-hornblende gneiss, and amphibolite with subordinate syenite-monzonite gneiss. Amphibolite-facies metamorphism",,K-Ar dates of Middle Jurassic for plutonic rocks and Late Triassic for metamorphic rocks,NB002,143,Nabesna,Metamorphic,5880
Mza,Anorthosite,Mesozoic,"Part of ""diorite complex."" Medium- to coarse-grained bytownite anorthosite with hypidiomorphic to allotriomorphic texture. Diopside pyroxene and gabbro pegmatite",,K-Ar dates of Middle Jurassic for plutonic rocks and Late Triassic for metamorphic rocks,NB002,146,Nabesna,Igneous,5880
PPa,Diorite Complex,Permian and Pennsylvanian,Altered diabase and gabbronorite,,,GU002,148,Gulkana,Igneous,5880
PPd,Diorite Complex,Permian and Pennsylvanian,"Diorite, granodiorite, and gabbronorite",,,GU002,149,Gulkana,Igneous,5880
Psm,Strelna Metamorphic Complex,Mesozoic or Paleozoic,"A diverse and intimately mixed group of low- to medium-grade greenschist and amphibolite which also includes abundant pelitic and psammitic schist, metachert, and gneiss having pronouced mortar structure. Contains no marble but does contain extensive massive to gneissose mafic to intermediate (meta?) plutonic rocks. Rocks are tightly folded on all scales and pervasively faulted; they are strongly foliated and partially mylonitic and are cut by post-metamorphic Late Jurassic and Early Cretaceous plutons. Has been thought to metamorphosed equivalent of the Strelna Formation or the Skolai Group, however it lacks any meta-limestone as would be expected for the Skolai Group. Unit is also similar to Triassic and Jurassic diorite complex of the Nabesna quadrangle.",,K-Ar age on hornblende from metagabbro of 152 +/- 6 Ma; thought to be reset.,VA002,5920,Valdez,Metamorphic,5920
Ja,Amphibolite facies rocks,Jurassic(?),"Portion of tectonic inclusion 10 by 15 km in McHugh Complex consisting of layered quartz gabbro, amphibolite, and orthogneiss. This unit consists of nondescript, amphibolite facies, weakly foliated to nonfoliated granular rocks of uncertain protolith. Many of the rocks are rich in feldspar and quartz and may have a sedimentary protolith. They are laced with numerous dike-like bodies of amphibolite that originate from underlying amphibolite and orthogneiss. The amphibolite-facies rocks are structurally complex and contain many lenses of incompletely serpentinized ultramafic and gabbroic rocks. Extensively retrograded to prehnite-pumpelllyite facies, as is surrounding McHugh Complex. Changed to Strelna per Winkler, 1998.",,,VA002,5921,Valdez,Metamorphic,5920
qmfs,Quartz-muscovite-feldspar schist; Metamorphic Complex of Gulkana River,Late Paleozoic (?) or older,Quartz-muscovite-feldspar schist,,,GU002,168,Gulkana,Metamorphic,5920
mmp,Metamorphosed pelitic and calc-schist; Metamorphic Complex of Gulkana River,Late Paleozoic (?) or older,Metamorphosed pelitic and calc-schist,,,GU002,169,Gulkana,Metamorphic,5920,,
Pas,"Strelna Metamorphics, Metasedimentary and metavolcanic rocks","Pennsylvanian, and older(?)",Metasedimentary and metavolcanic rocks. Dominantly interlayered quartz-feldspar mica schist and mica-quartz schist and subordinate marble beds or lenses.,,,BG002,191,Bering Glacier,Metamorphic,5920,,
JPhc,Haley Creek metamorphic assemblage,Late Jurassic and Pennsylvanian or older?,"Wrangellia terrane, Haley Creek metamorphic assemblage, Consists of Uranatina River metaplutonic unit (Jurassic and Pennsylvanian) and Strelna Metamorphics (Early Pennsylvanian and older?)",,,VA007,33,Valdez,Metamorphic,5625,,
Pm,Mankomen Group (undivided),Early Permian,"Thermally altered, weakly foliated, Mankomen Group. Wollaston-, diopside-, and garnet-bearing marble, calcareous metasiltstone and metasandstone, and pyroxene and hornblende hornfels",,,NB002,121,Nabesna,Metamorphic,5940,,HFS
Pm,Mankomen Group,Lower Permian,"Argillite with subordinate interbedded calcareous siltstone and grit. Alternating beds of argillite and siltstone, grading to silty limestone showing a ribbon-like appearance in the upper strata. Locally intruded by gabbro dikes and sills of Triassic age","Cephlapods, brachiopods, and corals indicate an Early Permian age",,NB108,544,Nabesna,Sedimentary,5940,,
Pe,Eagle Creek Formation,Early Permian,"Part of Mankomen Group. Thin-bedded argillite and siliceous siltstone, with interbedded of calcereous siltstone and sandstone, biomicritic limestone, and a pebble to cobble conglomerate. Gabbroic dikes and sills. Equivalent to parts of the Cache Creek Group and the Skolai Group","Daonella; Abundant brachiopods, cephalopods, corals, foraminifera, and bryozoan",,NB002,122,Nabesna,Sedimentary,5950,,
Pzm,Skolai Group -- marble unit,"Late Paleozoic, Middle Pennsylvanian to Early Permian","Subordinate light- or medium-gray and buff calcareous rocks, mostly recrystallized to marble but containing scanty fragments of fossils, interbedded with dark-gray calcareous siltstone and shale. Change unit designator to ma, per Winkler (1998)","Scanty fragments of bryozoans, crinoids, corals, and brachiopods.",,VA002,5955,Valdez,Metamorphic,5955,,
M,Haley Creek terrane -- schistose marble,mid-Cretaceous?,"Schistose marble. Individual marble layers can be traced for several km, however the layers vary greatly in thickness, terminate abruptly in places, and are generally thoroughly folded. Small isolated bodies of marble mark unmapped fault within the Haley Creek terrane.",,K-Ar ages on hornblende range from 122 to 148 Ma. A muscovite age is 133 +/- 4 Ma,VA002,2720,Valdez,Metamorphic,5955,,
Pm,Marble of the metamorphosed Skolai Group,Early Permian and Pennsylvanian,"Fine- to medium-grained banded impure marble, locally deformed. Interpreted as temporal equivalent of limestones of the Hasen Creek Formation",Poorly preserved Early Permian fossils,,MC002,22,McCarthy,Metamorphic,5955,,
Pasm,"Strelna Metamorphics, Marble",Early Pennsylvanian,"White to gray marble (m) forms conspicuous deformed and folded bands and pods throughout the unit. Individual marble beds vary markedly in thickness along strike; maximum .measured thickness of the unit is about 1,200 meters. The unit is commonly composed of 90 percent more strongly regionally metamorphosed calcite and lesser calc-silicate minerals. The marble is typically found in association with greenschist and quartz-rich schist, but also forms pods to a few hundred meters thick within predominantly phyllitic schist or as inclusions within associated metaplutonic rocks.",,,BG002,190,Bering Glacier,Metamorphic,5955,,
PPasc,Station Creek Formation,Early Permian and Pennsylvanian,"A volcanoclastics member, which grades from coarse volcanic breccia through volcanic graywacke to volcanilutite; Also a volcanic flow member, locally pillowed and brecciated, and includes altered lavas of andesites and basalts, and minor intercalated volcanoclastic rocks. Volcanoclastic member correlates with Early Permian Slana Spur Formation of Mankomen Group. Volcanic flow member correlates with parts of the Tetelna Volcanics in the Nabesna Quad. See also 5810 Permian(?) volcanic rocks.",,,MC002,18,McCarthy,Igneous,6120,,
PlPsc,Station Creek Formation,Pennsylvanian and Permian,Chlorite-rich amygdaloidal andesitic lava flows and volcaniclastic rocks. Correlative with the Tetelna Volcanics in the Nabesna quadrangle,,,MC003,310,McCarthy,Igneous,6120,,
PPasvc,Station Creek Formation - Volcaniclastic member,"Lower Permian, Early and Middle Pennsylvanian","A volcanic pebble conglomerate and coarse volcanic graywacke with subordinate intercalated broken-pillow breccia and volcanic flows. Mainly greenish-gray, the rocks are generally metamorphosed to greenschist",,,MC100,124,McCarthy,Metamorphic,6120,,
Pasmv,Station Creek Formation - Volcanic flow member,Pennsylvanian,Dark greenish-gray metaandesite or metabasalt flows and some compositionally similar broken-pillow lavas metamorphosed to greenschist. Pillow structures are preserved in several flows. The unit is locally cut by gabbro dikes.,,,MC100,125,McCarthy,Metamorphic,6120,,
PPt,Tetelna Volcanics,Permian and Pennsylvanian,"Volcanic flows of porphyritic andesite, volcanic mud and debris avalances, lapilli-pumice tuffs, and fine- to coarse-grained volcaniclastics ranging from mudstone to conglomerate, and volcanic-rich limestone. Areas of contact metamorphism creating foliated hornblende diorite and quartz monzonite, and amphibolite.",Brachiopods and cephalopods,,NB002,125,Nabesna,Igneous,6220,,
Pt,Tetelna Volcanics,Pennsylvanian,"Tetelna Volcanics, hornblende andesite and other volcanic rocks, metamorphosed to greenschist facies.",,,GU002,157,Gulkana,Metamorphic,6220,,
PPat,Tetelna Volcanics,Permian and Pennsylvanian,"Interbedded volcanic flows, volcanic mud and debris avalanches, lapilli-pumice tuffs, volcanic mudstone to volcanic sandstone, and volcanic pebble conglomerates all intruded by gabbro dikes and sills. Volcanic rocks chiefly andesite and dacite in composition. Lower part is considered Pennsylvanian by correlation with this formation in general area of its type section 75 km northwest (Richter and Dutro, 1975).",,,NB004,417,Nabesna,Igneous,6220
PPat,Tetelna Volcanics,Permian and Pennsylvanian,"Interbedded flows of andesite, massive lahars, lapilli-pumice tuffs, and volcaniclastic rocks ranging from mudstone to conglomerate, locally graded",,,NB108,545,Nabesna,Igneous,6220
Dl,Limestone,Devonian,Gray to dark-gray recrystallized limestone. Regionally metamorphosed (greenschist facies),Rugose and tabulate corals,,NB002,153,Nabesna,Metamorphic,6931
MzPzi,Diorite-gabbro,Devonian,"Dark-greenish-gray, fine- to coarse-grained augite- and hornblende-bearing mafic diorite and gabbro. Regionally metamorphosed (greenschist facies)",,,NB002,156,Nabesna,Metamorphic,7080
Pzk,Kaskawulsh Group of Kindle,Devonian (?) and Older (?) Paleozoic,"Mainly thick-bedded, fine- to coarse-grained, locally schistose, banded, or granulated marble, also schist, phyllite, and minor amphibolite, all strongly schistose.",Tabulate horn corals suggest a Devonian age,,MC002,23,McCarthy,Metamorphic,7220
Dkm,"Kaskawulsh Group, Calcschist",early Late or Middle Devonian,"Massive to thick-bedded, gray to white fine- to coarse-grained marble, dolomite, and muscovite-quartz-calcite schist; commonly complexly and tightly folded into isoclines.",Contains sparse tabulate corals and Amphipora of Middle or early Late Devonian age,,BG002,200,Bering Glacier,Metamorphic,7220
Pzm,Kaskawulsh Group -- marble,Devonian and older(?),"Massive to thin-bedded white, gray, and black marble in complexly folded beds and lenses totalling more than 1,000-m-thick.",,,MS002,95,Mount Saint Elias,Metamorphic,7220
Dl,Metasedimentary and meta-igneous rocks,Devonian and older (?),Coasre grained recrystallized limestone. Locally fossiliferous.,,,NB004,424,Nabesna,Metamorphic,7220
Dp,Phyllite,Devonian,"Dark- to light-gray phyllite and brownish-gray metaconglomerate, containing clasts of quartz mica schist, quartzite, calcareous mica schist, quartz-chlorite schist and thin marble lenses. Regionally thermally metamorphosed (greenschist facies)",,,NB002,152,Nabesna,Metamorphic,7230
Pzk,"Kaskawulsh Group, Metavolcanic rocks",Mississppian to Ordovician,"Chiefly schistose, fine-grained metaandesite tuff and flows, and coarse-grained breccia and conglomerate, along with minor dark-gray argillite. Metavolcanic and volcaniclastic rocks massive to crudely layered. Metavolcanic breccia and conglomerate contain fragments of fine-grained metavolcanic rocks as much as 1 cm diameter. Includes local metamorphosed hypabyssal intrusive rocks, chiefly meta-hornblende diorite..",,,BG002,210,Bering Glacier,Metamorphic,7240
Pav,"Metamorphic rocks between Border Ranges and Hubbard Faults, Metavolcanic rocks","Pennsylvanian, and older(?)",Mainly dark green metatuff with minor carbonate and chert,,,MS002,85,Mount Saint Elias,Metamorphic,7240
Pavs,"Metamorphic rocks between Border Ranges and Hubbard Faults, Metasedimentary and metavolcanic rocks","Pennsylvanian, and older(?)",Metasedimentary and metavolcanic rocks. Dominantly interlayered quartz-feldspar mica schist and mica-quartz schist and subordinate marble beds or lenses. ,,,MS002,83,Mount Saint Elias,Metamorphic,7240
Pav,"Metamorphic rocks between Border Ranges and Hubbard Faults, Metavolcanic rocks","Pennsylvanian, and older(?)",Mainly dark green metatuff with minor carbonate and chert,,,YA002,85,Yakutat,Metamorphic,7240
Pavs,"Metamorphic rocks between Border Ranges and Hubbard Faults, Metasedimentary and metavolcanic rocks","Pennsylvanian, and older(?)",Metasedimentary and metavolcanic rocks. Dominantly interlayered quartz-feldspar mica schist and mica-quartz schist and subordinate marble beds or lenses. ,,,YA002,83,Yakutat,Metamorphic,7240
Pzvp,Kaskawulsh Group -- interbedded metavolcanic and metasedimentary rocks,Devonian and older(?),"Foliated and doubly folded massive to thinly banded mafic metavolcanic rocks; typically greenschist, semischist to mica schist, and thin pods and beds of marble.",,,YA002,93,Yakutat,Metamorphic,7240
Pzv,Kaskawulsh Group -- metavolcanic rocks,Devonian and older(?),"Massive to thinly banded, green to greenish black recrystallized mafic volcanic rocks",,,YA002,91,Yakutat,Metamorphic,7240
Dms,Phyllite,Devonian,"Dark-gray phyllite, dark-gray to buff quartzite, calcareous quartzite, porcellanite, buff to light-gray calcareous quartz mica schist, and light-gray marble. Regionally metamorphosed (greenschist facies)",,,NB002,155,Nabesna,Metamorphic,7230,,,
Dp,Metasedimentary and meta-igneous rocks,Devonian and older (?),"Chiefly phyllite with subordinate schistose pebble conglomerate, containing stretched clasts of quartzite, limestone, schist, and phyllite, gray micaceous quartzite, and calcareous quartz-mica schist.",,,NB004,422,Nabesna,Metamorphic,7300,,,
Dhp,Metasedimentary and meta-igneous rocks,Devonian and older (?),Hornfelsed phyllite. Cordierite- and andalusite-bearing knotty schists peripheral mostly to the Mineral Cairn phase (Kmg) of the Tok-Tetlin pluton.,,,NB004,423,Nabesna,Metamorphic,7300,,HFS,
Dg,Greenstone,Devonian,Dark-greenish-gray massive greenstone. Locally contains thin septa of phyllite. Regionally metamorphosed (greenschist facies),,,NB002,154,Nabesna,Metamorphic,7320,,,
Dg,Metasedimentary and meta-igneous rocks,Devonian and older (?),"Massive greenstone, consisting of fine-grained epidote, chlorite, and altered feldspar with segregations of actinolite and occasional small phenocrysts of clinopyroxene. May be intrusive.",,,NB004,425,Nabesna,Metamorphic,7320,,,
Pzs,Quartz mica schist,Early(?) Paleozoic,"Tan, light-gray, and light-gray-green quartz-muscovite schist, quartz-muscovite-chlorite schist, dark-gray graphitic schist, and minor calcareous mica schist. Regionally metamorphosed (greenschist facies)",,,NB002,157,Nabesna,Metamorphic,7400,,,
Pzp,Kaskawulsh Group -- metasiltite,Devonian and older(?),"Dark-reddish brown weathering, black massive meta-siltstone interbedded with marble.",,,MS002,89,Mount Saint Elias,Metamorphic,7400,,,
Qa,Alluvium in streams,Holocene and Pleistocene,"Includes alluvium in active flood plains and in principal terraces of major and some minor streams. Chiefly stratified silt, sand, gravel, and boulders.",,,VA008,51,Valdez,Unconsolidated,105,,,1050
Qa,Alluvium in streams,Holocene and Pleistocene,"Includes alluvium in active flood plains and in principal terraces of major and some minor streams. Chiefly stratified silt, sand, gravel, and boulders.",,,VA006,6007,Valdez,Unconsolidated,105,,,1050
Qc,"Colluvium, undifferentiated",Holocene and Pleistocene,"Chiefly talus but includes deposits of small landslides, rock glaciers, and other mass-wasting processes. Generally includes a large proportion of alluvium in small fans and cones and reworked glacial deposits. Sand, gravel, boulders, diamicton, and rubble",,,VA006,6001,Valdez,Unconsolidated,107,,,1070
Qcb,Bluff Colluvium,Holocene and Pleistocene,"Occurs along high steep bluffs of the Copper River and its principal tributaries. Locally includes small areas of the Copper River deposits (Qcr) and the drift of older glaciations (Qg). Unsorted silt, sand, gravel, and boulders",,,VA006,6033,Valdez,Unconsolidated,107,,,1072
Ql,Landslide deposits,Holocene,"Slumps, earth-debris flows, block glides, and debris avalanches. Diamicton and rubble",,,VA006,6021,Valdez,Unconsolidated,108,,,1080
Qao,Older alluvium,Holocene and Pleistocene,"In higher terraces along larger streams and in inactive alluvial fans. Predominantly of Pleistocene age, but may include localized Holocene deposits. Chiefly well sorted gravel and sand; minor silt and boulders",,,VA008,53,Valdez,Unconsolidated,109,,,1090
Qao,Older alluvium,Pleistocene,"In higher terraces along larger streams and in inactive alluvial fans. Predominantly of Pleistocene age, but may include localized Holocene deposits. Chiefly well sorted gravel and sand; minor silt and boulders",,,VA006,6009,Valdez,Unconsolidated,109,,,1090
Qfl,Fluviolacustrine deposits,Holocene and Pleistocene,"In ponds, swamps, lagoons, and along low-gradient streams. Chiefly silt, clay, fine sand, peat, and other organic material",,,VA006,6013,Valdez,Unconsolidated,112,,,1120
Qms,Mineral spring and mud volcano deposits,Holocene and Pleistocene,"Deposited by warm, Na-HCO3-rich, CO2-charged, saline spring waters forming the Klawasi Group (Shrub, Upper Klawasi, and Lower Klawasi) mud volcanoes (Motyka and others, 1989) located west of Mount Drum. Also includes one or more inactive deposits west of Capital Mountain; a methane-charged mineral spring found on Copper River's east bank near Copper Center. Mud and clayey-silt",,,VA006,6037,Valdez,Unconsolidated,118,,,1180
Qe,Eolian deposits,Holocene,"Dunes on tops of river bluffs, windblown flats, and river bars. Includes informally named Bremner sand dunes, a large barchan field, located at confluence of Bremner and Copper Rivers. Fine-grained sand",,,VA006,6023,Valdez,Unconsolidated,120,,,1200
Qe,Eolian deposits,Holocene,"Dunes on tops of river bluffs, windblown flats, and river bars. Includes informally named Bremner sand dunes, a large barchan field, located at confluence of Bremner and Copper Rivers. Fine-grained sand",,,VA008,63,Valdez,Unconsolidated,120,,,1200
Qgl,Glaciolacustrine deposit,Quaternary,Interbedded lake and glacial deposits of the Copper River basin,,,VA008,57,Valdez,Unconsolidated,124,,,1240
Qcr,Copper River deposits,Quaternary,"Interbedded glaciolacustrine, glacial, and alluvial deposits. Includes deposits of glacial Lake Atna (Nichols, 1989; Williams and Galloway, 1986); historically complex basin built from numerous lake stages in response to multiple glacial advances and retreats. Locally overlain by small fine-grained alluvium and pond deposits (Qfl). Interbedded by the Mount Wrangell valley-fill lavas (Qwwv) along western margin of Mount Wrangell, especially in Chetaslina River valley area. Clay-pebble silt and diamicton, containing local to regionally distributed beds of gravel and sand",,,VA006,6015,Valdez,Unconsolidated,124,,,1240
overprint,Superglacial Drift,Quaternary,Superglacial Drift,,,VA006,6027,Valdez,Unconsolidated,126,,,1260
Qrg,Rock glacier deposits,Holocene,Well-defined lobate forms that may include glacier ice cores. Chiefly blocks of rubble,,,VA006,6005,Valdez,Unconsolidated,127,,,1270
Qag,Drift of Alaskan glaciation,Holocene,"Neoglacial deposits of end, lateral, and ground moraines, kames and outwash proximal to present glaciers; includes small rock glaciers. Diamicton, local gravel, and sand",,,VA006,6003,Valdez,Unconsolidated,130,,,1300
Kbc,"Bernard Creek terrane, deleted, now McHugh Complex",mid-Cretaceous?,"Mylonitic greenschist. Relict bedding and volcaniclastic textures are retained locally. Elsewhere unit is nearly massive, but cataclasis and neomineralization generally are so pervasive that they obliterate any primary features.",,,VA002,2190,Valdez,Metamorphic,2190,,,
Kfc,Fox Creek terrane Unit deleted on new VA map,mid-Cretaceous?,"Intercalcated lower greenschist and transistional blueschist facies metasedimentary and mafic metavolcanic rocks. Over broad areas the rocks have a cataclastic fabric, locally relict primary sedimentary and volcaniclastic textures are retained. Unit is distinguished from Bernard Creek terrane (unit Kbc) by the dominance of dark, very-fine-grained metapelitic rocks; where green metavolcanic rocks are present in the Fox Creek terrane they indistinguishable from greenschist of the Bernard Creek terrane.",,,VA002,2700,Valdez,Metamorphic,2700,,,
Khc,Haley Creek terrane,mid-Cretaceous?,"Metamorphosed complexly deformed and tectonically mixed plutonic and sedimentary rocks. Metaplutonic rocks are most abundant in southern part of the terrane and are compositionally diverse and weakly to strongly foliated. Although diorite and granodiorite are most abundant lithologies, compositions range from trondjhemite to hornblende gabbro and hornblendite. Amphibolite is is widespread within the metaplutonic rocks. Metasedimentary rocks are dominant in northern part of terrane where marble, metapelite, metapsammite are structurally mixed with subordinate metaplutonic rocks. Unit deleted and merged with Jag (NSA = 5245)",,,VA005,2700,Valdez,Metamorphic,5245,,,
Kvm,Valdez Group -- Amphibolite-facies flysch,Late Cretaceous,Flysch metamorphosed to amphibolite-facies schist,,,VA006,6029,Valdez,Metamorphic,2710,,,
JTrt,Talkeetna Formation,Early Jurassic and Late Triassic(?),"Dominantly andesitic volcaniclastic rocks, products of Late Triassic and Early Jurassic oceanic volcanic arc",Mollusks and brachiopods,,VA006,6041,Valdez,Igneous,3250,,,
Jnt,Ultramafic rocks,Middle or Early Jurassic,"Gabbro, pyroxenite, peridotite and dunite. Includes the Nelchina River Gabbronorite, the Tonsina ultramafic, and a mafic sequence of Winkler and others (1980). K-Ar dates indicate ages of 188-171 Ma",,K-Ar dates indicate ages of 188-171 Ma,VA006,6035,Valdez,Igneous,3340,,,
Jc,Chitina Valley batholith,Late Jurassic,"Compositionally diverse quartz monzodiorite, ranging from granite to diorite, generally foliated and locally gneissic particularly within plutons enclosed by the Strelna Metamorphics of Plafker and others (1989) (PPasm). K-Ar dates indicate plutonic ages of 157-138 Ma, foliated phase ages are as young as 122 Ma; synchronous with Late Jurassic major regional orogeny perhaps related to subduction along Border Ranges Fault",,"K-Ar dates indicate plutonic ages of 157-138 Ma, foliated phase ages are as young as 122 Ma",VA006,6031,Valdez,Igneous,3403,,,
Jnt,Mafic and ultramafic rocks,Early or Middle Jurassic,"Gabbro, pyroxenite, peridotite and dunite. Includes the Nelchina River Gabbronorite, the Tonsina ultramafic, and a mafic sequence of Winkler and others (1980).",,K-Ar dates indicate ages of 188-171 Ma,VA006,6036,Valdez,Igneous,3405,,,
Klc,Schist of Liberty Creek of Winkler and others (1981),Jurassic??,"Basalt flows, breccia, and tuff; regionally metamorphosed greenschist- and blueschist-facies Middle Jurassic or older oceanic assemblage protolith",,,VA006,6025,Valdez,Metamorphic,3610,,,
Trl,Chitistone and Nizina Limestones,Late Triassic (Karnian and Norian),"Light- to medium-gray limestone of diverse textural varieties and include minor dolomite lower in the sequence and nodules and lenses of dark-gray chert high in the sequence. Lower thicker-bedded sequence is Chitistone Limestone, upper, thinner-bedded sequence is Nizina Limestone.",,,VA005,4030,Valdez,Sedimentary,4030,,,
Trn,Nikolai Greenstone,Middle and (or) Late Triassic,"Weakly metamorphosed, lightly altered tholeiitic basalt that is characteristically amygdaloidal and poorly bedded. Metamorphosed to prehnite-pumpellyite facies",,K-Ar whole-rock isochron of 112 +/- 11 Ma thought to indicate collosion of Wrangellia with North America,VA005,4420,Valdez,Igneous,4420,,,
Psm,Strelna Metamorphic Complex,Mesozoic or Paleozoic,"A diverse and intimately mixed group of low- to medium-grade greenschist and amphibolite which also includes abundant pelitic and psammitic schist, metachert, and gneiss having pronouced mortar structure. Contains no marble but does contain extensive massive to gneissose mafic to intermediate (meta?) plutonic rocks. Rocks are tightly folded on all scales and pervasively faulted; they are strongly foliated and partially mylonitic and are cut by post-metamorphic Late Jurassic and Early Cretaceous plutons. Has been thought to metamorphosed equivalent of the Strelna Formation or the Skolai Group, however it lacks any meta-limestone as would be expected for the Skolai Group. Unit is also similar to Triassic and Jurassic diorite complex of the Nabesna quadrangle.",,K-Ar age on hornblende from metagabbro of 152 +/- 6 Ma; thought to be reset.,VA005,5920,Valdez,Metamorphic,5920,,,
Tos,"Orca Group -- sedimentary rocks, undivided",Paleocene and Eocene?,"Marine argillite, siltstone, sandstone, and conglomerate. Argillite and siltstone are more abundant than the coarser-grained rocks. Well-bedded, repetitive finer-grained and coarser-grained strata; primary sedimentary features are diagnostic of deposition by sediment-gravity flow. Finer-grained facies dominate west of Valdez Arm. Conglomerate clasts are of diverse extrabasinal lithologies.",,,VA005,950,Valdez,Sedimentary,950,,,
Qc,"Colluvium, undifferentiated",Holocene and Pleistocene,"Chiefly talus but includes deposits of small landslides, rock glaciers, and other mass-wasting processes. Generally includes a large proportion of alluvium in small fans and cones and reworked glacial deposits. Cheifly poorly sorted silt, sand, gravel, and boulders.",,,VA008,55,Valdez,Unconsolidated,107,,,1071
Qyg,Drift of younger (Wisconsin) glaciation,Pleistocene,"Well defined lateral moraines high on the valley walls of the Dadina, Chetaslina, and East Fork of the Chetaslina Rivers. Diamicton.",,,VA008,59,Valdez,Unconsolidated,135,,,1350
Qg,Drift of older glaciations,Pleistocene,"Wisconsin glaciation and older end, lateral, and ground moraines local kames, kame-like deposits, and outwash. Also includes the glaciolacustrine deposits (Qcr) near complex interface with glacial Lake Atna in lower Chitina River valley. Chiefly diamicton, local gravel and sand",,,VA006,6011,Valdez,Unconsolidated,135,,,1350
Qyg,Drift of younger (Wisconsin) glaciation,Pleistocene,"Well defined lateral moraines high on the valley walls of the Dadina, Chetaslina, and East Fork of the Chetaslina Rivers. Diamicton.",,,VA006,6017,Valdez,Unconsolidated,135,,,1350
Qcf,Chetaslina volcanic debris flow,Pleistocene,"Multi-colored, voluminous debris avalanche deposit containing megablocks of both porphyritic and aphanitic andesite lava, hydrothermally altered lava, volcanic breccia, pyroclastic flow deposits, lacustrine sediments, and glacial deposits.",,,VA008,65,Valdez,Igneous,312,,,3120
Qvd,Volcanic debris flow,Pleistocene,"Chetaslina volcanic mass-flow deposit, probably sourced from Mount Drum, exposed along Chetaslina and Copper Rivers; Sanford volcanic debris flow exposed along Sanford and Copper Rivers. Large blocks of lava and varied debris",,,VA006,6019,Valdez,Igneous,312,,,3120
Qpf,Pyroclastic flows,Pleistocene,"The extensive informally named Nadina hot avalanche deposit resulting from Mount Drum's cataclysmic eruption and a smaller pyroclastic flow (0.3 Ma) possibly derived during an explosive episode from Mount Drum deposited at Chetaslina River's two forks. Abundant bombs, scoria, pumice, and ash; lesser andesite and dacite blocks",,Whole rock K/Ar age of 342 ka from a scoria bomb,VA006,6045,Valdez,Igneous,314,,,3140
PPas,"Skolai Group, undivided",Early Permian and Pennsylvanian,"Lower late Paleozoic magmatic arc and associated upper sedimentary rocks. Equivalent to the Mankomen Group (Pe, Pel, and PPass) and the Tetelna Volcanics (PPat) in northern Wrangell Mountains and eastern Alaska Range",,,VA006,6039,Valdez,Metamorphic,5625,,,
,Not mapped,,Not mapped,,,YA002,98,Yakutat,,98,,,
Qbc,"Cinder cones, flows, and tuffs","Quarternary, Pleistocene",Olivine basalt and basaltic andesite,,,GU003,3110,Gulkana,Igneous,320,,,3200
Jc,Chitina Valley batholith,Late Jurassic,"Compositionally diverse quartz monzodiorite, ranging from granite to diorite, generally foliated and locally gneissic particularly within plutons enclosed by the Strelna Metamorphics of Plafker and others (1989) (PPasm). K-Ar dates indicate plutonic ages of 157-138 Ma, foliated phase ages are as young as 122 Ma; synchronous with Late Jurassic major regional orogeny perhaps related to subduction along Border Ranges Fault",,"K-Ar dates indicate plutonic ages of 157-138 Ma, foliated phase ages are as young as 122 Ma",VA006,6043,Valdez,Igneous,3403,,,
,Not mapped,,Not mapped,,,MS002,98,Mount Saint Elias,,98,,,
Qsg,Superglacial drift,Quaternary,Superglacial drift,,,MC004,413,McCarthy,Unconsolidated,126,,,1260
Qwws,Shield lavas -- Mount Wrangell volcano,"Holocene and Pleistocene, 0.65 Ma and younger",Chiefly andesitic flows,,,MC006,429,McCarthy,Igneous,301,,,3011
Qvd,Volcanic debris flows,Pleistocene,"Chetaslina volcanic mass-flow deposit, probably sourced from Mount Drum, exposed along Chetaslina and Copper Rivers; Sanford volcanic debris flow exposed along Sanford and Copper Rivers. Large blocks of lava and varied debris",,,MC006,420,McCarthy,Igneous,312,,,3120
Qvd,Volcanic debris flows,Pleistocene,"Chetaslina volcanic mass-flow deposit, probably sourced from Mount Drum, exposed along Chetaslina and Copper Rivers; Sanford volcanic debris flow exposed along Sanford and Copper Rivers. Large blocks of lava and varied debris",,,MC006,440,McCarthy,Igneous,312,,,3120
Qvd,Shield and intracaldera lavas -- Mount Jarvis volcanoes,"Pleistocene, 1.7-1.0 Ma",Extensive flat-lying andesitic flows,,,MC006,430,McCarthy,Igneous,355,,,3551
QTw,Lava flows and sedimentary rocks -- Older volcanic and sedimentary rocks,"Pleistocene, Pliocene, or Miocene",Flat-lying andesite and dacite lava flows; a Tertiary tillite and the fossil-rich conglomeratic sandstone Frederika Formation,,,MC006,439,McCarthy,Igneous,455,,,4550
QTwr,Domes and intrusive rocks -- Older volcanic and sedimentary rocks,"Pleistocene, Pliocene, or Miocene",Chiefly dacite and rhyolite,,,MC006,416,McCarthy,Igneous,465,,,4650
Tw,Lava flows and lahars -- Older volcanic rocks,Miocene or Oligocene,"Basaltic andesite, andesite, and dacite lava flows; andesitic lahar deposits",,,MC006,427,McCarthy,Igneous,1040,,,
Tw,Lava flows and lahars -- Older volcanic rocks,Miocene or Oligocene,"Basaltic andesite, andesite, and dacite lava flows; andesitic lahar deposits",,,MC006,434,McCarthy,Igneous,1040,,,
Tw,Lava flows and lahars -- Older volcanic rocks,Miocene or Oligocene,"Basaltic andesite, andesite, and dacite lava flows; andesitic lahar deposits",,,MC006,436,McCarthy,Igneous,1040,,,
Tg,Granodiorite -- Hypabyssal and plutonic rocks,"Pleistocene, Pliocene, Miocene, or Oligocene","Plutonic phase of the Wrangell Lava exposed mainly at Hawkins Glacier head, marginal to Mount Blackburn volcano caldera",,,MC006,435,McCarthy,Igneous,1250,,,
Ku,Marine sedimentary rocks -- Wrangellia terrane,Early and Late Cretaceous,"Sandstone and siltstone deposited at shallow to moderate depths; locally abundant marine fossils. Includes the MacColl Ridge, Chititu, Schulze, and Moonshine Creek Formations",,,MC006,438,McCarthy,Sedimentary,1940,,,
KJm,Mlange units -- Valdez Group,"mid-Cretaceous, Jurassic(?), and Late Triassic","Tholeiitic pillowed basalt, chert, tuff, greywacke, argillite, and phyllite-greenstone deposited along a convergent plate margin as early as Late Triassic continuously into middle Cretaceous. Includes the McHugh Complex, a structurally complex and chaotic assemblage of oceanic rocks containing abundant slightly deformed radiolarian chert; and a mlange-like unit between the McHugh Complex and the Valdez Group (Kv)",,,MC006,423,McCarthy,Tectonite,2190,,,
Kv,Greenschist-facies flysch -- Valdez Group,Late Cretaceous,"Flysch metamorphosed to lower greenschist-facies. Mainly mudstone and graywacke turbidite beds, carbonaceous phyllite, minor mafic tuff and breccia in a thick regionally extensive belt of accreted flyschoid deep marine rocks. Metamorphic grade increases southward from lower greenschist-facies to amphibolite-facies",,,MC006,437,McCarthy,Metamorphic,2700,,,
Jc,Chitina Valley batholith,Late Jurassic,"Compositionally diverse quartz monzodiorite, ranging from granite to diorite, generally foliated and locally gneissic particularly within plutons enclosed by the Strelna Metamorphics of Plafker and others (1989) (PPasm). K-Ar dates indicate plutonic ages of 157-138 Ma, foliated phase ages are as young as 122 Ma; synchronous with Late Jurassic major regional orogeny perhaps related to subduction along Border Ranges Fault",,"K-Ar dates indicate plutonic ages of 157-138 Ma, foliated phase ages are as young as 122 Ma",MC006,414,McCarthy,Igneous,3403,,,
JTrm,McCarthy Formation,Early Jurassic and Late Triassic,"Spiculite, impure chert and limestone, and shale deposited in a starved marine basin environment",Fossils locally abundant,,MC006,417,McCarthy,Sedimentary,3820,,,
Trl,Triassic limestone,Late Triassic,"Locally fossil-rich, thin-bedded limestone and interbedded argillite in partially starved marine basin; overlies shallow marine to intertidal fossil-poor cherty massive limestone",Fossils locally abundant,,MC006,431,McCarthy,Sedimentary,4029,,,
Trcn,Chitistone and Nizina Limestones,Late Triassic,"Chiefly limestone and dolomite; minor chert and marble; locally fossil rich. The upper Chitistone and cherty Nizina deposited in a shallow to moderately deep marine neritic environment; transition into an intertidal-supratidal setting with local sabkha facies full of algal-mat chips, stromatolites, and evaporate relics typical of the dolostone-rich lower Chitistone rocks",,,MC006,426,McCarthy,Sedimentary,4030,,,
Trn,Nikolai Greenstone,Late and Middle Triassic,"Altered tholeiitic basalt. Largely subareial, locally submarine in northeastern part of quadrangle. where basal sections contain pillow basalt and intercalated argillite. elsewhere, base generally characterized by volcanic conglomerate as much as 70-m-thick. Consists dominantly of pahoehoe and aa flows between 15-cm- and 15-m-thick; some flow tops are brecciated. Characteristically amygdaloidal except interiors of thicker flows. Typically altered and metamorphosed to prehnite-pumpellyite facies",,,MC002,29,McCarthy,Igneous,4420,,,
Trn,Nikolai Greenstone,Late and(or) Middle Triassic,"Widespread sequence of tholeiitic flood basalt flows, mainly subaerial and characteristically amygdaloidal, include subordinate volcaniclastic interbeds and volcanic conglomerate basal sections. Metamorphosed to prehnite-pumpellyite facies although alteration rarely masks primary mineralogy and texture. Contains anomalously high amounts of copper",,,MC006,418,McCarthy,Igneous,4420,,,
PPas,"Skolai Group, undivided",Early Permian and Pennsylvanian,"Lower late Paleozoic magmatic arc and associated upper sedimentary rocks. Equivalent to the Mankomen Group (Pe, Pel, and PPass) and the Tetelna Volcanics (PPat) in northern Wrangell Mountains and eastern Alaska Range",,,MC006,433,McCarthy,Igneous,5325,,,
PPasm,Strelna Metamorphics of Plafker and others (1989),"Jurassic(?), Triassic(?), Permian, Early Pennsylvanian, and Late Mississippian(?)","Dominantly calcareous metasedimentary rocks, schist, phyllite, amphibolite, and marble; lesser quartzite, meta-andesite, and metabasalt in thin to thick thrust sheets containing local pods of the tectonically emplaced ultramafic rock and marble (PPam); overlying the gabbro and orthogneiss (Pago). Includes the Jurassic Uranatina Metaplutonic Complex and the Dadina Schist of Carboniferous and possibly older(?) age exposed near Mount Drum. Metamorphic grade increases closer to the Chitina Valley batholith (Jc) and might represent metamorphosed roots of the Skolai-Tetelna magmatic arc (PPat, PPas, and PPasc)",,,MC006,419,McCarthy,Metamorphic,5625,,,
PPam,Marble,"Permian, Early Pennsylvanian?",Regionally metamorphosed with poorly preserved and locally placed Permian and Early Pennsylvanian fossils. Partially equivalent to the Permian limestone of the Hasen Creek Formation (Pl),,,MC006,415,McCarthy,Metamorphic,5955,,,
PPasc,Station Creek Formation,Early Permian and Pennsylvanian,"Magmatic arc consists of a younger volcaniclastic member and an older andesitic and basaltic lava flow member, both of submarine origin; locally metamorphosed to greenschist-facies south of Chitina Fault",,,MC006,441,McCarthy,Igneous,6120,,,
orange,Orthogneiss,Age not given,Metamorphosed plutonic rocks. Mostly Ti2 plutons within the gneissic core of the complex,,,CV006,509,Cordova,Metamorphic,2715,,,
Qa,Alluvium ,Holocene,In active streambeds and lowest terraces along larger streams and active alluvial fans. Chiefly well sorted gravel and sand; minor silt and boulders,,,CV004,703,Cordova,Unconsolidated,105,,,1050
Qu,"Slope deposits, undifferentiated",Holocene and Pleistocene,"Colluvium consisting of talus and small landslides, also includes small glacial, rock glacier, and alluvial deposits. Sand, gravel, boulders, diamicton, and rubble",,,CV004,701,Cordova,Unconsolidated,107,,,1070
Ql,Landslide deposits,Holocene and Pleistocene,"Slumps, earth-debris flows, block glides, and debris avalanches. Diamicton and rubble",,,CV004,713,Cordova,Unconsolidated,108,,,1080
Qao,Older alluvium,Holocene and Pleistocene,"In higher terraces along larger streams and in inactive alluvial fans. Predominantly of Pleistocene age, but may include localized Holocene deposits. Chiefly well sorted gravel and sand; minor silt and boulders",,,CV004,705,Cordova,Unconsolidated,109,,,1090
Qao,Older alluvium,Holocene and Pleistocene,"In higher terraces along larger streams and in inactive alluvial fans. Predominantly of Pleistocene age, but may include localized Holocene deposits. Chiefly well sorted gravel and sand; minor silt and boulders",,,CV004,705,Cordova,Unconsolidated,109,,,1090
Qao,Older alluvium,Holocene and Pleistocene,"In higher terraces along larger streams and in inactive alluvial fans. Predominantly of Pleistocene age, but may include localized Holocene deposits. Chiefly well sorted gravel and sand; minor silt and boulders",,,CV004,705,Cordova,Unconsolidated,109,,,1090
Qao,Older alluvium,Holocene and Pleistocene,"In higher terraces along larger streams and in inactive alluvial fans. Predominantly of Pleistocene age, but may include localized Holocene deposits. Chiefly well sorted gravel and sand; minor silt and boulders",,,CV004,705,Cordova,Unconsolidated,109,,,1090
Qfl,Fine-grained deposits,Holocene,"In ponds, swamps, lagoons, and along low-gradient streams. Chiefly silt, clay, fine sand, peat, and other organic material",,,CV004,707,Cordova,Unconsolidated,112,,,1120
Qb,Beach and delta deposits ,Holocene,"Wave-deposited, coarse-grained material and driftwood along seacoast; fine-grained sediment in mud flats of Copper River Delta; and marine uplift terraces. Successive spit-building episodes of progressive gradation are preserved in beach sequences along coastal lowland between Cape Yakataga and Bering Glacier. Boulders, gravel, sand, and silt",,,CV004,703,Cordova,Unconsolidated,115,,,1150
Qb,Beach and delta deposits ,Holocene,"Wave-deposited, coarse-grained material and driftwood along seacoast; fine-grained sediment in mud flats of Copper River Delta; and marine uplift terraces. Successive spit-building episodes of progressive gradation are preserved in beach sequences along coastal lowland between Cape Yakataga and Bering Glacier. Boulders, gravel, sand, and silt",,,CV004,709,Cordova,Unconsolidated,115,,,1150
Qe,Eolian deposits ,Holocene,"Dunes on tops of river bluffs, windblown flats, and river bars. Includes informally named Bremner sand dunes, a large barchan field, located at confluence of Bremner and Copper Rivers. Fine-grained sand",,,CV004,715,Cordova,Unconsolidated,120,,,1200
Qag,Drift of Alaskan glaciation,Holocene,"Neoglacial deposits of end, lateral, and ground moraines, kames and outwash proximal to present glaciers; includes small rock glaciers. Diamicton, local gravel, and sand",,,CV004,711,Cordova,Unconsolidated,130,,,1300
Qt,Talus,Holocene,"Larger areas of poorly sorted, angular deposits forming cones and aprons at the base of steep slopes",,,MS002,1,Mount Saint Elias,Unconsolidated,107,,,1071
Th,Hypabyssal rocks,Tertiary,"Dacite, andesite, and rhyodacite porphyry. Typically strongly porphyoritic. Correlates with younger porphyry of Nabesna quadrangle and with hypabyssal rocks associated with the Wrangell Lava in Alaska and Canada",,K-Ar on biotite of 3.8+0.8 m.y. and sanidine of 6.5+0.2 m.y.,MC002,31,McCarthy,Igneous,1055,,,