McGRATH QUADRANGLE

(Alder Gulch) (Cr.) Antimony, Bismuth, Gold, Tungsten
McGrath district McGrath (2.35, 12.15)
MF-379, loc. 21 62942'N, 155°43'W

Geologically similar to Candle Cr. Between 1929 and 1933 about 65 oz

of gold was recovered from a cut of about 13,600 £2, Large boulders
hampered the hand operation. Concentrates contained considerable scheel-
ite, some magnetite, stibnite, and bismuth, and no cinnabar. See also
(Candle Cr.).

(Black Cr.) Gold
McGrath district(?) McGrath(?)

Placer mining in 1930 reported. Location of creek not known; may not
be in McGrath quadrangle.

(Bowser Cr.) Copper, Gold, Lead, Silver, Zinc
McGrath district McGrath (18.75-18.9, 3.45-3.7)
MF-379, locs. 11-13 62911'-62912'N, 153942'-153°43 'W

Argentiferous galena, sphalerite, pyrrhotite, and minor chalcopyrite in
replacement bodies and fissure veins in Paleozoic limestone cut by intru-
sive breccia, a small body of granodiorite porphyry, and felsic and mafic
dikes, all of probable Tertiary age. Sulfides also as fracture fillings
in breccia. Hornfels developed in limestone and pelitic rocks around some

intrusive bodies. Samples contained as much as 3.4 ppm Au and 309.8 ppm
Ag.

(Candle Cr.) Gold, Mercury, Monazite(?), Silver,
Tungsten

McGrath district McGrath (1.55-1.85, 15.3-15.75)

MF-379, loc. 20 62°53'-62°54'N, 155°46'-155°49'W

Small quartz monzonite pluton of Late Cretaceous-early Tertiary age intruded
Cretaceous shale and sandstone. Basalt at extreme head of creek. Gold in
placers probably derived from quartz veins in quartz monzonite and mineral-
ized sandstone and shale near contact. Gold, some in nuggets of as much as
2 0z, accompanied by much cinnabar (some recovered, retorted, and the mer-
cury sold for local use) and magnetite; smaller amounts of scheelite and
monazite(?). Placer deposits probably represent residual accumulations

that are nearly in place and have been forming since late Tertiary. Gold
discovered in 1913. Dredge operated 1918-26. Recorded production through
1950 was 129,500 oz gold and 12,210 oz silver.

AlQ


Probably a contact-metamorphic deposit that contains disseminated chalco-
pyrite.

(Telaquana Pass) Molybdenum
Aniak district Lake Clark (21.75, 16.6) approx.

60°56'N, 153°27'W aprox.

Molybdenite associated with quartz, pyrite, and magnetite in a Tertiary
composite granitic pluton.

(Telaquana R.) Molybdenum
Aniak district Lake Clark (20.7, 16.3) approx.

60°55'N, 153°34'W approx.

Molybdenite in pyritized zones in Tertiary quartz diorite; schistose roof
pendants.

(Twin Lakes, east) Copper

Bristol Bay region Lake Clark (19.6, 12.8) approx.
60°43'N, 153°43'W approx.

Chalcopyrite and bornite, generally with pyrrhotite, in andesitic volcanic
rocks near Tertiary granite.

(Iwin Lakes, west) Copper, Lead, Zinc
Bristol Bay region Lake Clark (18.7, 11.9) approx.

50°40'N, 153°50'W approx.

Pyrite, sphalerite, chalcopyrite, and galena in silicified Tertiary
felsic volcanic rocks; mainly in volcanic breccia.

(Upper Tazimina) Copper
Bristol Bay region Lake Clark (18.1, 2.1) approx.

60°06'N, 153°55'W approx.

Apparently small contact-metamorphic deposits near contact between Cre-
taceous or Tertiary granitic rocks and older metavolcanic rocks. Nearby
deposit said to be similar contains disseminated chalcopyrite, its alter-
ation products, and minor amounts of other ore minerals.

(West Ospook) Copper, Molybdenum
Bristol Bay region Lake Clark (18.25, 2.4) approx.

60°07'N, 153°55'W approx.

Probably a porphyry-type deposit; contains pyrite with some chalcopyrite,
magnetite, and molybdenite; mainly localized near contact between Creta—

Al3


Unnamed occurrence Copper

McGrath district McGrath (1.1, 15.25)
62952'N, 155°52'W

Visible chalcopyrite blebs in Cretaceous porphyritic basalt.

Unnamed creek Copper, Lead, Zinc

McGrath district McGrath (19.2, 6.5)
MF-379, locs. 8, 24 62°21'N, 153°39'W

Sulfide minerals in small veinlets and along shear zones near contact
between Paleozoic limestone, argillite, and siltstone and a large Ter-
tiary igneous complex. Samples of bedrock and a stream cobble contain
pyrrhotite, pyrite, galena, chalcopyrite, and sphalerite.

Unnamed occurrence Copper, Nickel
McGrath district McGrath (12.75, 3.6)
MF-379, loc. 17 62°12'N, 154°27'w

Minor amounts of scattered copper-nickel sulfides in partially serpentin-
ized peridotite that intrudes complexly folded Paleozoic limestone and

argillite; may have been emplaced along a segment of Farewell fault. Maxi-
mum exposed dimension is 50 ft.

Unnamed occurrence Fluorite, Rare-earth elements, Thorium,

Uranium

McGrath district McGrath (15.8, 1.4)

62°04'N, 154°05'W
Sample of eudialite-bearing dike associated with peralkaline granite of
the Tertiary Windy Fork pluton contains 33.3 ppm U and 46.3 ppm Th. Ew
dialite (zirconium- and rare-earth-bearing silicate) is an abundant
mineral in quartz—amphibole-potassium feldspar pegmatite veins that cut
the granite and adjacent sedimentary rocks near the north end of the plu-

ton. Purple fluorite is the most abundant accessory mineral; zircon and
rare allanite also present.

Unnamed occurrence Fluorite, Thorium, Uranium

McGrath district McGrath (15.95, 1.05)
62°02'N, 153°04'W

Uranium content of 5 anomalously radioactive grab samples of peralkaline
granite of the Tertiary Windy Fork Pluton averages 25.5 ppm (range - 19.9-
29.1 ppm); thorium content averages 295 ppm (range - 169-404 ppm); average
Th/U ratio is 11.4, about 3 times that of background samples. Radioactivity
is apparently concentrated in unidentitifed yellow-green crystals that may
be uranothorite or thorianite. Fluorite is a ubiquitous accessory mineral.
Some uranium has been mobilized and redeposited along joint surfaces.

A23


greenstone near contact with Jurassic? granitic plutons. Prospective ore
said to be rich, but in small bodies. Prospect located in 1905, but has
been inactive for many years. Includes references to Keyes.

(Diamond Point) Gold(?)
Redoubt district Lliamna (21.05, 11.7)
MF-364, loc. 8 59°39'N, 153°38'W

Jurassic quartz monzonite intruded Triassic limestone and greenstone and
Lower Jurassic volcanic rocks. Both granitic and country rocks shattered
and impregnated with veins and stringers of pyrite. Rocks highly stained
from oxidation of pyrite, but no other mineralization noted. Assays of
about 0.1 oz/ton Au rumored.

Durand Copper, Iron
Bristol Bay region Iliamna (17.65, 12.65)
MF-364, loc. 4 59°43'N, 154°00'W

A quartz vein 10 ft wide in Lower Jurassic schistose greenstone was ex-
plored by 2 pits before 1909. Vein contains pyrite, chalcopyrite, mala-
chite, and azurite. In same area a magnetite occurrence has been staked
as an iron prospect; probably similar to that at Chenik Mtn.

Duryea (& Duryea) Copper, Gold, Lead, Silver, Zinc

Bristol Bay region Iliamna (18.4, 12.3)
MF-364, loc. 6 59°41'N, 153°56'W

Claims staked 1901 or 1902. Argentiferous galena-sphalerite vein in brec-
ciated Triassic limestone. Minor chalcopyrite, pyrite, and limonite in
weathered rock. Mineralized zone continues for about 2 km with average
width of about 23 m; manganiferous gossan containing 2-6 oz/ton Ag near
eastern end of mineralized zone. In 1909 claim owners reported that samp-
les contained 80-196 oz/ton Ag, about 1 oz/ton Au, 35%-50% Pb, and 15%—
20% Zn. Extensive underground workings (caved by 1949), but no record of
production. Includes reference to Duryea & McNeil.

Dutton (Mining & Development Co.) Copper, Gold(?), Molybdenum, Silver(?),

Bristol Bay region Iliamna (18.1, 12.15)
MF-364, loc. 5 59°41'N, 153°58'W

Skarn in zone about 200ft wide and 3,000 ft long in brecciated limestone
(now largely marble) along contact with greenstone (both of Late Triassic
age); both cut by small porphyritic andesite dikes. Skarn laced by inch-
thick veinlets containing quartz, calcite, chalcopyrite, and pyrite; a
little molybdenite and malachite also present. One old report, but no
recent ones, mentions small amounts of gold and silver. Marble also con-

a4


Chip Loy Nickel

McGrath district McGrath (13.35, 3.05)
MF-379, loc. 18 62°10'N, 154°23'wW

Nickel-bearing pyrrhotite in an irregular zone of massive bodies as much

as 11 ft wide and disseminated bodies as much as 150 ft wide along the side
of a diabase pipe(?) in silicified and folded lower Paleozoic limestone and
slate. Mineralized zone has a strike length of more than 1,100 ft. No
data on Ni content of pyrrhotite; little if any high-grade ore. A few
other pyrrhotite occurences in vicinity.

(Fluorite Cr.) Fluorite, Gold, Silver
McGrath district McGrath (14.3-15.05, 2.9-3.35)
MF-479, loc. 25 62909'-62911'N, 154°10'-154915'W

Float of gossan material scattered along creek; apparently representative
sample contained 0.06 oz/ton Au and 0.16 oz/ton Ag. One 5-in cobble of
green fluorite was found.

(Hippie Cr.) Lead, Silver
McGrath district McGrath (19.1, 5.0)
MF-379, loc. 9 62°16'N, 153°40'W

Dike swarms and small stocklike bodies of Tertiary porphyritic felsic
rocks in Paleozoic limestone with small amounts of argillite and silt—
stone. Calcite vein (apparently along a fault) 6 in to6 ft wide in lime-
stone contains pyrite and argentiferous galena in scattered grains and
discontinuous bands 1-10 in wide; minor arsenopyrite. As determined by
fire assay of one sample Au is less than 0.02 ppm and Ag is 2.2 oz/ton.

(Hippie Cr., South Fork) Lead, Silver
McGrath district McGrath (18.7, 4.15)
MF-379, loc. 10 62°13'N, 153°43'W

Narrow shear zone in Paleozoic massive gray limestone 2 ft from contact

with and parallel to a 20-ft-thick pyrite-bearing Tertiary felsite por-
phyry sill. Shear zone is discontinuously mineralized; chiefly calcite,
pyrite, and galena. Sample contained more than 1,000 ppm (about 30 oz/

ton) Ag.

(Ozzna Cr.) Lead, Zinc
McGrath district McGrath (17.0, 5.7)
MF-379, loc. 23 62°19'N, 153°55'W

Stream heads in small, probably quartz diorite, intrusive body. Boulders
of pyrrhotite and sphalerite, pyrite-pyrrhotite-galena-sphalerite-arseno-

A20


(Sheep Cr., Rat Fork) Copper, Lead, Silver, Zinc

McGrath district McGrath (17.3-17.85, 5.8-6.3)
MF-379, locs. 4, 5 62°19'-62°20'N, 153°49'-153°53'W

Small intrusive body (probably Tertiary quartz diorite) near head of stream.
Quartz diorite porphyry dikes cut Paleozoic limestone and argillite in
nearly vertical cirque walls near head of creek (MF-379, loc. 4); skarn
zones 2-10 ft wide contain pyrrhotite, sphalerite, and chalcopyrite. Boul-
ders of pyrrhotite and sphalerite, pyrite-pyrrhotite-galena-sphalerite-
arsenopyrite, or pyrite and magnetite near headwaters of creek and in talus
slopes. Sample from one boulder assayed 9.6 oz/ton Ag, more than 10% Pb,
and 7% Zn. Near mouth of creek (MF-379, loc. 5) a highly oxidized fault(?)
zone between Paleozoic argillite and limestone is about 8-10 ft wide. Sel-
ected sample of oxidized material included pyrrhotite with subordinate
sphalerite, galena, and chalcopyrite that replaced silicated limestone.

(Tin Cr. tributary) Copper, Zinc
McGrath district McGrath (18.95, 8.5)
MF-379, locs. 2, 22 62°28'N, 153°40'W

Paleozoic limestone within 2-5 ft of a narrow malachite-stained shear is
altered to a yellowish gray color; sparse sulfides (chiefly chalcopyrite)
are localized within a foot of the shear for about 20 ft along dip. Stream
cobble contains pyrrhotite with subordinate sphalerite and chalcopyrite.

(White Mtn.) Mercury
McGrath district McGrath (9.3-9.4, 2.95-3,3)
MF-379, locs. 14-16 62°10'-62°11'N, 154951'-154°52'wW

Located in 1958; produced more than 400 flasks (14+ tons) of mercury be-
tween 1964 and 1974. Cinnabar, without significant Sb or As, localized in
veinlets, breccia fillings, and as disseminations in dolomitized Middle?
Ordovician limestone along southeast-dipping, mainly bedding-plane, faults
that probably are part of the Farewell fault system. Some replacement of
dolomite by cinnabar. Only igneous rock found in immediate vicinity isa
basaltic dike altered to clay, carbonate minerals, and fine-grained silica
that was uncovered in a prospect trench.

Unnamed occurrence Copper
McGrath district McGrath (13.3, 3.05)
MF-379, loc. 18 62°10'N, 154°23'W

Narrow, gossan-capped vein of pyrrhotite(?) and chalcopyrite in silicified
lower Paleozoic limestone-slate bedrock. Malachite and azurite in gossan.

A22


diorite near shear zone. Float downslope from small oxidized zones con-
tains disseminated chalcopyrite, bornite, other sulfide minerals, and
tourmaline.

Unnamed occurrences Copper, Gold, Molybdenum, Zinc
McGrath district Lime Hills (21.05-21.15, 8.9-9.05)
MF-412, loc. 9 . 61°29'-61930'N, 153°29'wW

Quartz cobbles contained (1) less than 2% molybdenite; (2) less than 10%
sphalerite and pyrite in veinlets 1-3 mm wide; and (3) 40% pyrrhotite and
minor chalcopyrite. Sample from one cobble contained 12 ppm Au. Area
underlain by upper Mesozoic metasedimentary rocks.

Unnamed occurrence Copper, Lead, Silver, Zinc
Aniak district Lime Hills (19.25, 8.45)
MF-412, loc. 7 61°28'N, 153°42'wW

Boulder, 2 ft in diameter, of sulfide breccia that contains angular frag-
ments of volcanic rock. 60% sulfide minerals, chiefly galena, with sub—
ordinate sphalerite, bournonite, chalcopyrite, and pyrite; sample contained
3,000 ppm Ag. Tertiary? volcanic rocks in nearby cirque are locally altered.

Unnamed occurrence Copper, Lead, Zinc

McGrath district Lime Hills (24.7, 12.15)
MF-412, loc. 13 61°40'N, 153°02'w

Mineralized float in a small cirque; samples of Tertiary granodiorite,
altered felsic rock, sulfides, and vein quartz contained chalcopyrite,
pyrrhotite, sphalerite, galena, and pyrite.

Unnamed occurrences Copper, Zinc
McGrath district Lime Hills (20.3, 10.8)
MF-412, loc. 6 61°936'N, 153°34'W

Relatively unmetamorphosed upper Mesozoic shale, argillite, and graywacke
cut by faults or shear zones and about a mile from a small Tertiary?
granitic body contain disseminated sulfide minerals, narrow veins of
massive sulfide minerals, and quartz veins with minor sulfide contents.
Sulfides in samples include arsenopyrite, pyrite, pyrrhotite, chalco-
pyrite, and (in one probably exotic boulder) sphalerite.

Unnamed occurrence Fluorite, Lead, Thorium, Uranium, Zinc(?)
McGrath district Lime Hills (23.25, 12.65)
61°42'N, 153°12'w

Sample of sericitized alkali-feldspar granite porphyry of the Tertiary
Styx River batholith contained 14.8 ppm U and 38.3 ppm Th. Grab samples

Al7


Principal site of prospecting and placer mining in Mulchatna basin. Small-
scale exploitation since 1912; mining on Bonanza and Scynneva Creeks since
1957; total production from Bonanza Cr. and tributaries probably not more
than 3,000 oz of gold. Valley has been glaciated; erratics reworked into
creek gravels. Bedrock is Jurassic shale, argillite, siltstone, and minor
amounts of fine conglomerate cut by fine-grained felsic dikes of Cretaceous
or Tertiary age. A mineralized shear zone contains quartz veins with pyrite,
arsenopyrite, and a little gold. Quartz-carbonate vein 0.5 m thick contains
disseminated galena. Includes reference to (Big Bonanza Cr.).

(Bonanza Hills) Antimony, Copper, Gold, Lead, Silver
Bristol Bay region Lake Clark (12.1-13.5, 12.5-13.75)

60°43 '-60°47'N, 154°26'-154°36'W

Jurassic, Cretaceous, and lower Tertiary volcanic and sedimentary rocks
cut by many small Cretaceous-Tertiary quartz monzonite bodies and by dikes
associated with volcanic rocks are hosts for quartz-sulfide vein deposits.
Sulfides include tetrahedrite, arsenopyrite, galena, chalcopyrite, pyrite,
and stibnite. Analyses of samples indicated as much as 1.25 oz/ton Au and
3 or more oz/ton Ag.

(Currant Cr.) Copper
Bristol Bay region Lake Clark (17.9, 6.1) approx.

60°20'N, 153°46'W approx.

Pyrite and chalcopyrite in a Tertiary volcanic-intrusive complex.

(Franklin Gulch) Gold
Bristol Bay region Lake Clark
SENEX% quad.

Gold prospects have been found in this and other headwaters of the Kijik R.

(Ingersol Gulch) Gold
Bristol Bay region Lake Clark
S4NE% quad.

Gold prospects have been found on this and other headwaters of the Kijik R.

(Kasna Cr.) Copper, Iron, Zinc
Bristol Bay region Lake Clark (17.0, 3.0)
MF-378, loc. 5 60°09'N, 154°03'W

Lenticular body (possibly discontinuous) of Triassic limestone and dolomite
between volcanic rocks and cut off on south end by Tertiary granodiorite is
cut by dikes and sills of porphyritic basalt. Parallel zones as much as

Ag


Knutson Copper, Gold, Silver(?)

Bristol Bay region Tliamna (15.2, 14.9)
MF-364, loc. 3 59°50'N, 154°17'W

A quartz vein 3-8 ft thick that cuts Cretaceous or Tertiary granitic
rock contains copper minerals, gold, and probably silver. A 40-ft tunnel
was driven in 1912, but there has been no recorded production.

(Koktuli R.) Gold

Bristol Bay region Iliamna
NW% quad.

Fine flour gold on river bars.

(Lake Fork area) Copper, Gold, Silver
Redoubt district Iliamna (13.65, 4.45)
MF-364, loc. 17 59°15'N, 154°29'wW

An igneous breccia zone about 45 m wide in Jurassic quartz diorite in-
truding hornblende gabbro contains many sulfide-rich veins; principal

ore mineralsare pyrite, chalcopyrite, and malachite. Selected samples
contained as much as 6.5% Cu and more than 0.5 oz/ton of both Au and Ag.
A partially caved adit in the breccia shows meager sulfide mineralization.

(Marsh Cr.) Copper, Iron

Redoubt district Iliamns (23.25, 14.8)
MF-364, loc. 10 59°49'N, 153°22'W

Small magnetite occurrence in Triassic metamorphosed sedimentary and vol-
canic rocks in a fault block. A vein of chalcopyrite with malachite and
azurite 6-12 in. thick in marble. Includes reference to (Clearwater Cr.).

McNeil(-Cook) Copper, Gold, Silver
Redoubt district Iliamna (12.3, 2.45)
MF-364, loc. 20 59°08'N, 154°38'W

Series of small tactite skarn deposits formed by intrusion of Cretaceous

or Tertiary granodiorite into volcanic and calcareous rocks of the Jurassic
and Triassic Talkeetna and Kamishak Fms. Largest body extends for about

760 m along contact between volcanic and sedimentary rocks along Crevice

Cr. Chalcopyrite and pyrite are most abundant sulfides; some chalcocite,
malachite, and azurite present. Developed 1913-20, claims dropped in 1926,
relocated in 1953. Developed by pits and a 60-ft tunnel. Test shipments

of ore in 1914 and 1916 (about 12 tons) averaged 17.55% Cu, about 0.12 oz/
ton Au, and 15 oz/ton Ag. Includes references to: Cook & Bornland, (Crevice
Cr.), (Okchiak Cr.). See also (Paint R.).

A6


tains lenses and beds of magnetite-rich rock. Extensive development 1902-
05, but no ore was shipped.

(Fog Pond) Copper(?), Gold
Bristol Bay region Iliamna (14.6, 9.1)
MF-364, loc. 14 59°31'N, 154°22'W

Mafic volcanic rocks intruded by felsic dikes(?) and possibly by quartz
porphyry; all are now altered. Porphyry contains widespread pyrite and
scattered grains that are probably chalcopyrite, though analyses of samples
taken in a geochemical reconnaissance are low in copper. Selected speci-
mens from shear zones contain pyrite stringers and as much as 37.7 ppm Au..

(Frying Pan Lake) Iron, Vanadium
Bristol Bay region Iliamna (5.95, 15.1)
MF-364, loc. 1 59952'N, 155°20'W

Plutonic breccia is 50%-90% pyroxenite blocks made up largely of pyroxene
and magnetite in a matrix of Late Cretaceous or Tertiary granodiorite.
Analyses showed iron as FeO, 16%-24%; Ti09, about 1.3%; P205, 0.1%-3.2%;
vanadium, 0.1%-0.15%. Includes reference to (Iliamna Lake).

(Iliamna Lake) Zeolites

Bristol Bay region Iliamna (6.5-15.75, 7.25-13.75)
59°22'-59°47'N, 154914'-155°16'N

Clinoptilolite, mordenite, heulandite, and minor amounts of laumontite
occur as alteration products of nonmarine Tertiary tuffs and other vol-
canic rocks and sedimentary rocks derived from them along the shores of
Iliamna Lake and on islands in the lake. Zeolitized beds are as much as
a few tens of feet thick and underlie areas with exposed lengths of as
much as a few hundred feet. See also (Frying Pan Lake.)

(Iniskin Bay) Iron
Redoubt district Iliamna (22.95, 13.6)
MF-364, loc. li 59°45'N, 153°24'W

Small occurrences of magnetite in metamorphosed volcanic rocks of the Lower
Jurassic Talkeetna Fm. near younger Jurassic granitic rocks.

(Iniskin R.) Copper
Redoubt district Iliamna (22.6, 14.5)
MF-364, loc. 9 59°48'N, 153°27'W

Copper sulfide(s) near contact between Jurassic or older metamorphic rocks
and Jurassic quartz monzonite and diorite.

AS


of radioactive hornblende granite contained as much as 882 ppm U. Uranium
is enriched along iron-stained joint surfaces, which also contain galena,
arsenopyrite, and sphalerite(?). Purple fluorite is an abundant accessory
mineral of the granite.

Unnamed occurence Fluorite, Thorium, Uranium
McGrath district Lime Hills (23.3, 13.4)

61°44'N, 153°12'W

Sample of Tertiary biotite granite porphyry of the Jimmy Lake stock con-
tained 35.4 ppm U and 42.3 ppm Th. The low Th/U ratio of 1.20 suggests
uranium enrichment. Another sample contained 15.1 ppm U and 45.8 ppm Th.
Accessory minerals include fluorite and rare allanite.

Unnamed occurrence Lead, Silver, Zinc
McGrath district Lime Hills (24.15, 9.2) approx.

61930'N, 153°07'W approx.

Float of silver-bearing veins that contain abundant galena and sphalerite.

Unnamed occurrence Molybdenum
McGrath district Lime Hills (19.3, 13.05)
MF-412, loc. 3 61944'N, 153°41'W

A quartz vein 2 in wide in upper Mesozoic quartz diorite contains less than
2% finely disseminated molybdenite.

Unnamed occurrence Monazite(?), Rare-earth elements
McGrath district Lime Hills (15.85, 8/2)
MF-412, loc. 2 61°27'N, 154°07'W

Sample of Tertiary biotite granite of Tired Pup batholith contained abundant
accessory allanite and also monazite and/or xenotime, which are characteris-—
tic acccessory minerals of the main batholithic mass.

Unnamed occurrence Monazite(?), Rare-earth elements
McGrath district Lime Hills (14.8, 9.8)
MF-412, loc. 1 61°33'N, 154°14'wW

Sample of Tertiary biotite granite of Tired Pup batholith contained abundant
accessory allanite and also monazite and/or xenotime, which are character-
istic accessory minerals of the main batholithic mass.

Al8


Unnamed prospect Iron

Redoubt district Iliamna (13.8, 4.55)
MF-364, loc. 21 59°15'N, 154°28'w

Magnetite-rich segregations in Jurassic mafic intrusive rocks.

Unnamed prospect Iron
Redoubt district Iliamna (18.95, 9.3)
MF-364, loc. 23 59°31'N, 153°52'w

Magnetite-bearing zones in Jurassic mafic plutonic rocks.

Unnamed prospect Iron
Bristol Bay region Iliamna (17.3, 11.75)
MF-364, loc. 24 59°39'N, 154°03'W

Average magnetite content of samples of Triassic greenstone within a few
tens of meters of a contact with Cretaceous or Tertiary granodiorite is
about 5%. Near Meadow Lake.

Unnamed prospect Iron
Redoubt district LIliamna (19.9, 12.1)
MF-364, loc. 25 59°41'N, 153°45'W

Magnetite-bearing Jurassic mafic plutonic rocks.

Unnamed prospect Iron
Redoubt district Tliamna (21.5, 12.6)
MF-364, loc. 26 59°42'N, 153934'W

Magnetite-bearing Jurassic mafic plutonic rocks.

Unnamed prospect Iron
Bristol Bay region Iliamna (18.1, 13.2)
MF-364, loc. 27 59°44'N, 153°58'W

Magnetite-bearing Jurassic mafic plutonic rocks.

LAKE CLARK QUADRANGLE

(Bonanza Cr.) Lead, Gold
Bristol Bay region Lake Clark (9.2-11.5, 12.15-13.25)
MF-378, locs. 1, 6 60°42'-60°45'N, 154°40'-154°51'W

A8


Synonyms, Owners, Operators, and Claim Names

Iliamna quadrangle
Alaska Katmalite Corp. -- see (Augustine I.)

Black Prince -- see Copper King

Cook & Bornland -- see McNeil

Copper King Ledge -- see Millet

(Crevice Cr.) -- see McNeil

Duryea & McNeil -- see Duryea

Dutton, Goodro & Thomas -- see Dutton
Dutton Mining (& Milling) Co. -- see Dutton
Ida G. -- see Duryea

Keyes -- see Copper King

Knudsen -- see Knutson

(Koktalee R.) -- see (Koktuli R.)

McNeil, Holly and others -- see McNeil
(Okchiak Cr.) -~ see McNeil

Pan American Petroleum Corp. -- see (Chenik Mtn.), unnamed iron prospects
Plaff -- see (Battle Lake)

Reward-Ridgway -- see McNeil

St. Eugene Mining Corp., Ltd. -- see Millet
Sargent -- see McNeil

Silver Bell -- see Duryea

Success -- see Durand

War Eagle -- see Duryea

Lake Clark quadrangle

Barnes -- see (Kasna Cr.)

Belle -- see (Kasna Cr.)

(Big Bonanza Cr.) -- see (Bonanza Cr.)
Bowman -- see (Portage Cr.)

Brooks & von Hardenberg -- see (Kasna Cr.)
(Caribou Cr.) -- see (Koksetna R.)

Cook -- see (Kasna Cr.)

Cyanide -- see (Kasna Cr.)

Edwards -- see (Kasna Cr.)

Gill -- see (Bonanza Cr.), (Portage Cr.)

Gilt Edge -- see (Kasna Cr.)

Gleason -- see (Kijik R.)

Hardenberg -- see (Kasna Cr.)

(Keejik R.) -- see (Kijik R.)

Kendall -- see (Kasna Cr.)

(Kijak R.) -- see (Kijik R.)

King -- see (Kasna Cr.)

Melish, Walker & King -- see (Mulchatna R.)
Millett -- see (BonanzaCr.), (Portage Cr.)
Morris -- see (Kasna Cr.)

Peary -- see (Kasna Cr.)

Platsburg -- see (Kasna Cr.)

Rabbit Foot Two -- see (Portage Cr.)

St. Eugene Mining Corp., Ltd. -- see (Kasna Cr.)
(Scenneva Cr.) -- see (Scynneva Cr.)
Shamrock Ledge -- see (Kasna Cr.)

Thompson -- see (Kijik R.)

A24


UNITED STATES DEPARTMENT OF THE INTERIOR
GEOLOGICAL SURVEY

SUMMARIES OF DATA ON AND LISTS OF REFERENCES TO
METALLIC AND SELECTED NONMETALLIC MINERAL OCCURRENCES
IN THE ILIAMNA, LAKE CLARK, LIME HILLS, AND McGRATH
QUADRANGLES, ALASKA

SUPPLEMENT TO OPEN-FILE REPORT 76-485

PART A -- SUMMARIES TO JANUARY 1, 1981

By
Edward H. Cobb and Bruce L. Reed

Open-File Report 81-1343A
1981

This report is preliminary and has not been
reviewed for conformity with U.S. Geological
Survey editorial standards.


Two modes of mineral occurrence; (1) quartz veins and pegmatites that contain
molybdenite and pyrite and cut basalt and granite; and (2) silicifed shear
zones that contain lead, copper, and zinc minerals and silver. See also
(Kasna Cr.).

(Lincoln Gulch) Gold
Bristol Bay region Lake Clark

S$NE% quad.

Gold prospects have been found on this and other headwaters of the Kijik R.

(Little Tazimina) Copper
Bristol Bay region Lake Clark (17.6, 1.25) approx.

60°04'N, 153°59'W approx.

Contact-metamorphic deposits that contain disseminated chalcopyrite and
its alteration products and minor amounts of other ore minerals; near con-
tact between Cretaceous or Tertiary granitic rocks and older metavolcanic
rocks.

(Mulchatna R.) Gold
Bristol Bay region Lake Clark
NW% quad.

Gold, not in paying quantities, in most river bars. Some gold on bedrock
on some of smaller tributaries. Most prospecting in 1890's and, possibly,
early 1900's. See also (Bonanza Cr.).

(Neacola R.) Copper, Molybdenum
Redoubt district Lake Clark (25.1, 17.4) approx.

60°58'N, 153°03'W approx.

Copper minerals associated with pyrite and some molybdenite in Tertiary
granitic rocks.

(Otter Lake) Copper, Zinc
Bristol Bay region Lake Clark (19.0, 8.75) approx.

60°29'N, 153°48'W approx.

Pyrite-rich deposits that contain some chalcopyrite and sphalerite; in
schists largely of volcanic derivation; both mafic and felsic volcanic
rocks involved.

All


250 ft wide and 1,050 ft long were contact metamorphosed to skarn consisting
of specular hematite, chalcopyrite (that contains fine grains of sphalerite),
magnetite, pyrite, amphibole, chlorite, calcite, garnet, and quartz. Deposit
discovered in 1906. Has been considerable drilling and trenching, which
proved the existence of a deposit of several million tons of material con-
taining slightly less than 1% Cu and about 27% Fe; there has been no pro-

duction. Includes references to: Hardenberg and to claims near Kontrashibuna
Lake.

(Kellet Cr.) Gold

Bristol Bay region Lake Clark
S4NE% quad.

Gold prospects have been found on this and other headwaters of the Kijik R.

(Kijik Lake) Copper, Silver
Bristol Bay region Lake Clark (13.75, 5.9) approx.

60°20'N, 154°25'W approx.

Silicified zones in porphyritic and brecciated Tertiary? dacite contain
pyrite and some chalcopyrite and silver.

(Kijik R.) Copper, Gold, Lead, Manganese, Molyb-
denum, Silver, Zinc

Bristol Bay region Lake Clark (13.75-14.6, 6.25-6.5) approx.

MF-378, locs. 2-4 (in part) 60°21'-60°22'N, 154°19'-154925'W approx.

A shear zone in Tertiary granitic rocks that cut Lower Jurassic rocks (MF-
378, locs. 3, 4) contains arsenopyrite with a little argentiferous galena,
chalcopyrite, sphalerite, and pyrite in a gangue of calcite and rhodochros-
ite. Graniticfloat (MF-378, loc. 2) contains some molybdenite and possibly
a little gold. Placer gold present in alluvium of some headwater tribu-—
taries. Includes references to: Gleason, (Keejik R.), (Kijak R.), Thompson.
See also: (Franklin Gulch), (Ingersol Gulch), Kellet Cr.), (incoln Gulch).

(Koksetna R.) Gold
Bristol Bay region Lake Clark
SW% quad.

Fine gold has been found. No mention of placer mining. Includes references
to (Caribou Cr.)

(Kontrashibuna Lake) Copper, Lead, Molybdenum, Silver, Zinc
Bristol Bay region Lake Clark (17.3-17.7, 2.9)
MF-378, loc. 10 60°09'N, 153°59'-154°01'W

ALO


Millet Copper, Gold, Silver

Bristol Bay region Iliamna (13.2, 13.9)
MF-364, loc. 2 59°47'N, 154°31'W

Mineralized Triassic limestone bordered on west by volcanic rocks of Jur-
assic Talkeetna Fm.; volcanic breccia to south is Tertiary. Mineralized
dikes that cut limestone are probably offshoots of Cretaceous or Tertiary
granodiorite body that lies alongeast side of deposit. Most of samples
analyzed contained less than 1% Cu; a few contained 3%-4% Cu with minor
amounts of Au and Ag. Mineralized zone is 6-12 m wide and has been traced
on surface for about 1,000 m. Deposit was explored before 1915 by open
cuts and a shallow shaft. Extensive U.S. Bureau of Mines drilling and
trenching program in 1949-50. No record of any production.

(Mirror Lake) Copper
Bristol Bay region Iliamna (11.3, 4.2) approx.

56°15'N, 154°44'W approx.

Chalcopyrite and pyrite in quartz vein in shear zone in Tertiary volcanic
rocks. Copper content low and volume of copper-bearing rock probably small.

(Paint R.) Copper, Iron
Redoubt district Iliamna (12.2, 2.6)
MF-364, loc. 19 59°08'N, 154939'W

Contact-metamorphic deposits consisting of tactite bodies in Jurassic vol-
canic and Triassic sedimentary rocks at or near contacts with younger grano—
diorite. One large tactite body is epidote-garnet rock with abundant actin-
olite and lesser amounts of calcite, quartz, pyrite, and chalcopyrite.

Other tactites are magnetite and quartz. Chalcopyrite is in sulfide lenses
that may be as large as 3 ft by 10 ft and contain more than 7% Cu or is
disseminated. Magnetite-quartz bodies are as large as 75 ft by 10 ft con-
taining very little quartz or smaller bodies with 50% quartz. Magnetic

data suggest the presence of other unexposed bodies. See also McNeil.

(Upper Copper Lake) Copper, Molybdenum, Silver
Bristol Bay region Iliamna (16.55-16.9, 10.5-10.9
MF-364, locs. 12, 13 59°35'-59°37'N, 154°06-154°08'W

Minor showings of molybdenite and chalcopyrite in pyritized and altered
Tertiary(?) intrusive rocks. A little Ag in some samples.

(Ursus Cove) Copper
Redoubt district Iliamna (19.85, 9.45)
MF-364, loc. 15 approx. 59°931'N, 153°46'W

Bedrock occurrence of copper sulfide. Symbol for locality 15, MF-364 is
1.25 mi SW of actual location.

Av


pyrite, or pyrite and magnetite in stream bed and in talus slopes.

(Ozzna Cr. tributary) Lead, Silver, Zinc
McGrath district McGrath (16.8, 5.4)
MF-379, loc. 3 62°18'N, 153°57'W

Stream drains part of a circular Tertiary igneous body 2 mi in diameter
(may be a breccia pipe) that is surrounded by complexly folded Paleozoic
argillite, limestone, and siltstone. Talus chiefly coarse igneous breccia.
Felsic and mafic dikes (relations to main breccia body not known) cut sed-
imentary rocks. Sulfide minerals exposed in valley wall along shear zones
in a felsic dike; small pods and lenses of pyrrhotite (containing euhedral
pyrite crystals), sphalerite, and argentiferous galena; selected sample
contained 52.2 oz/ton Ag; a 10-ft chip sample across 2 pods contained less
that 4% oz/ton Ag. Another lens along a fault zone that shows intensive
hydrothermal alteration contains pyrrhotite, sphalerite, and argentiferous
galena; selected sample contained 70-4 oz/ton Ag.

(Post R., West Fork) Copper, Zinc
McGrath district McGrath (17.45, 0.55)
MF-379, loc. 19 62°01'N, 153°53'W

Minor chalcopyrite and sphalerite in small lenses and disseminations of
pyrrhotite in mafic dikes in Paleozic argillite adjacent to a small Ter-
tiary stock. Lithology of stock not reported.

(Roundabout Mtn.) Copper, Nickel
McGrath district McGrath (3.25, 15.7) approx.
MF-379, loc. 1 62°54'N, 155°35'W approx.

Sample sent to U.S. Geological Survey in about 1919 contained pyrite,
chalcopyrite, and a trace of nickel. Country rock is lower Paleozoic
(Devonian) limestone and shale.

(Sheep Cr.) Zinc
McGrath district McGrath (18.0-18.15, 5.65-5.9)
MF-379, locs. 6, 7 62°19'N, 153°47'-153°48'W

Small stock of Tertiary quartz monzonite or granodiorite porphyry cuts
Paleozoic limestone, siltstone, and argillite. Shear zones in altered
felsite porphyry dikes in sedimentary rocks near north side cf stock
contain small lenses of sphalerite and pyrrhotite. Discontinuous veins
and pods of pyrrhotite in sedimentary rocks near dikes in vicinity.

\ A21


ILIAMNA QUADRANGLE

(Augustine I.) Pumice

Redoubt district Iliamna (22.9, 6.4)
59°20'N, 153°27'W

Volcanic cone mainly of fragmental material with subordinate trachitic
and andesitic lavas. A deposit of pumice at an altitude of 1,250 ft is
about 10 ft thick, 300 ft long, and probably about 50 ft wide and was
partly mined, as were other thinner (up to 3 ft) deposits in lower part
of island, between 1946 and 1949. Material barged to Anchorage and used
for making building blocks. Coordinates above are for the large deposit.
Eruptions since 1949 have causedconsiderable local changes, cut off road
to large deposit, and destroyed several buildings.

Aukney Gold(?)
Bristol Bay region Iliamna (6.6, 7.25)

59°25'N, 155°16'W

Claim, presumably staked for gold, on cliff of pyritiferous quartz latite
tuff. Only work was a little blasting on cliff face at shore of Lake
Iliamna.

(Battle Lake) Copper, Gold, Silver
Bristol Bay region Iliamna (10.15, 1.95)
MF-364, loc. 18 59°06'N, 154°53'w

Quartz vein cutting Tertiary locally propylitized interbedded volcanic
breccia and dacitic flows contains visible gold, chalcopyrite, pyrite,
malachite, and unidentified silver-sulfosalt mineral(s). Vein is from
a few cm to 2 m wide and exposed for a discontinuous strike length of
at least 300 m. Selected samples contained as much as 1,247 g/ton Au,
5,783 g/ton Ag, and several percent Cu. Mineralization is sporadic and
the results of a drilling program in 1965 were not encouraging.

(Chenik Mtn.) Iron
Redoubt district Iliamna (15.6, 4.4)
MF-364, loc. 22 59°15'N, 154°16'W

Magnetite-rich segregations in Jurassic mafic plutonic rocks. Deposit
probably of contact-metamorphic origin and low grade.

Copper King Copper, Iron
Redoubt district Iliamna (20.8, 12.15)
MF-364, loc. 7 59°41 'N, 153939'W

Chalcopyrite- and magnetite-bearing skarns in Lower Jurassic? marble and

A3


ceous or Tertiary granite and older metavolcanic rocks.

Unnamed occurrence Copper, Zinc

Aniak district Lake Clark (21.2, 16.75) approx.
60°56'N, 158°31'W approx.

Pyrite, pyrrhotite, and minor amounts of chalcopyrite and sphalerite in
Tertiary granite and in metasedimentary roof pendants.

LIME HILLS QUADRANGLE

(Another R.) Lead, Molybdenum, Zinc

Redoubt district Lime Hills (23.35, 3.25) approx.
61°09'N, 153°15'W approx.

Molybdenite- and pyrite-bearing disseminations and quartz veins in Tertiary
granitic rocks; local galena- and sphalerite-bearing veins nearby.

Chill Copper, Gold, Lead, Silver, Zinc
Redoubt district Lime Hills (24.75, 9.0)
MF-412, loc. 16 61°29'N, 153°03'W

Boulder of mafic rock contains 30% massive chalcopyrite and pyrite; cobble
of tourmaline-quartz rock with 20% disseminated arsenopyrite, pyrite, and
chalcopyrite; cobble of altered felsic rock with 3% disseminated pyrite
and galena and limonite and malachite on fracture surfaces. One sample
contained 0.2 ppm Au and 200 ppm Ag; others contained 30-100 ppm Ag. In
vicinity claims have been staked on porphyry-type copper deposits related
to Tertiary granitic rocks, on sulfide-rich float that contains sphalerite
and pyrite, and on a quartz-tourmaline-sulfide vein. Name used only in
MacKevett and Holloway, 1977 (OF 77-169F) of references listed in Part B.

(Chilligan R.) Lead, Zinc
Redoubt district Lime Hills (23.35, 8.45)
MF-412, loc. 15 61°27'N, 153°13'W

Galena and sphalerite, mainly in shear zones in metamorphic rocks near
complex Tertiary and Cretaceous granitic plutons; local porphyry-type

mineralized zones in plutons. Float of altered quartz monzonite on a

medial moraine contains 5%-10% galena, sphalerite, and pyrite.

(Jimmy Lake) Copper, Fluorite, Lead, Molybdenum, Zinc
McGrath district Lime Hills (23.3, 13.45)
MF-412, loc. 11 61°44'N, 153°12'W

Mineralized rock in altered parts of a biotite granite stock that intruded
sedimentary rocks and possibly overlying Tertiary volcanic rocks. Stock

Al4


Unnamed occurrence Antimony

McGrath district Lime Hills (20.2, 11.75)
MF-412, loc. 4 61939'N, 153935'W

Massive stibnite blocks up to a foot across in frost-heaved rubble near top
of a ridge and in talus. Area underlain by upper Mesozoic argillite and
graywacke near Cretaceous? granitic pluton. Float samples probably very
close to source. Deposits probably localized along faults or shear zones.

Unnamed occurrence Copper
Aniak district Lime Hills (19.65, 5.6) approx.

61°18'N, 153°40'W approx.

Chalcopyrite, pyrite, and pyrrhotite as blebs and disseminations in meta-
sedimentary rocks near Tertiary granite.

Unnamed occurrence Copper
McGrath district Lime Hills (21.05, 9.5)
MF-412, loc. 8 61°31'N, 153°29'W

Boulders of brecciated Tertiary quartz diorite and diorite gneiss contain
tourmaline and 15% chalcopyrite. One sample contained 5% pyrite.

Unnamed occurrence Copper
McGrath district Lime Hills (22.45, 10.45)
MF-412, loc. 10 61°34'N, 153°19'W

A small body of Tertiary quartz monzonite cuts upper Mesozoic slates and

graywacke and a probably Cretaceous monzonite stock. The quartz monzonite
contains traces of disseminated chalcopyrite and sparse fractures locally
contain quartz, chalcopyrite, and minor amounts of other sulfide minerals.

Unnamed occurrence Copper
McGrath district Lime Hills (20.2, 10.8)
MF-412, loc. 5 61°36'N, 153°35'W

Float and quartz veins in faulted or sheared relatively unmetamorphosed
upper Mesozoic sedimentary rocks about a mile from a small intrusive body
of probably Tertiary granitic rock contain sulfide minerals, including
pyrite, arsenopyrite, chalcopyrite, and pyrrhotite.

Unnamed occcurences Copper
McGrath district Lime Hills (24.6, 12.5)
MF-412, loc. 12 61°41'N, 153°03'W

Shear zone in Tertiary granodiorite contains chalcopyrite and other sul-
fides; malachite and azurite stains and traces of chalcopyrite in grano-

Al6




McGrath quadrangle
Blackburn & Eldridge -- see (Candle Cr.)

Cordero Mining Co. -- see (White Mtn.)
Egnati -- see (White Mtn.)

Egnaty -- see (White Mtn.)

Ignaty -- see (White Mtn.)

Kuskokwim Dredging Co. -- see (Candle Cr.)
Lyman -- see (White Mtn.)

Mary Margaret -- see (White Mtn.)

Mary Margie -- see (White Mtn.)

Peggy Barbara -- see (White Mtn.)

Red Devil -- see (Candle Cr.)

Strandberg & Sons, Inc. -- see (Candle Cr.)
(Vinasale) -- see (Alder Gulch) (Cr.)

A25


Introduction

This report was prepared as a supplement to a 1976 report which sum-
marized data on mineral occurrences in part of southwestern and west-cen-—
tral Alaska (Cobb, E. H., 1976, Summary of references to mineral occurrences
(other than mineral fuels and construction materials) in the Iliamna, Lake
Clark, Lime Hills, and McGrath quadrangles, Alaska: U.S. Geological Survey
Open-File Report 76-485, 101 p.). As a result of suggestions from users of
the series of which the 1976 report is a part, this supplement is released
in two parts; Part A, which presents summaries of data to January 1, 1981,
and Part B, which consists of reference lists for each occurrence.

In Part A data from most reports released between the cut-off date
(January 1, 1976) for the original report and January 1, 1981, have been
incorporated in new or rewritten summaries. Some of the original summaries
have also been expanded. For each occurrence described in Part A, the name,
U.S. Bureau of Mines mining district, reference (if any) that has the occur-
rence plotted on a map at a scale of 1:250,000, list of mineral commodities,
and location data are in the same format as in the 1976 report. Also in-
cluded at the end of Part A are updated lists of synonyms, owners, opera-
tors, and claim names.

In both parts citations are in standard bibliographic format with the
exception that references to reports and maps in numbered publication
series also show, in parentheses, an abbreviation for the report or map
series and the number of the report or map. Abbreviations used are:

AOF Alaska Division of Geological and Geophysical Surveys
Open-File Report

B U.S. Geological Survey Bulletin

BMB U.S. Bureau of Mines Bulletin

Cc U.S. Geological Survey Circular

GC Alaska Division of Geological and Geophysical Surveys
(and predecessor State agencies) Geochemical Report

GR Alaska Division of Geological and Geophysical Surveys
(and predecessor State agencies) Geologic Report

I U.S. Geological Survey Miscellaneous Geologic Investi-
agtions Map

Ic U.S. Bureau of Mines Information Circular

OF U.S. Geological Survey Open-File Report

MF U.S. Geological Survey Miscellaneous Field Studies Map

Pp U.S. Geological Survey Professional Paper

RI U.S. Bureau of Mines Report of Investigations

TDM Alaska Territorial Department of Mines Pamphlet

In Part B each citation to the principal references used in preparing
summaries in Part A is preceded by an asterisk. The form of citation used
in the reference list for each occurrence is considered sufficient identi-
fication for each numbered report or map to be found easily in most lib-
raries. Complete references to reports without identifying numbers are
listed at the end of Part B.

Al


Pass Copper, Lead, Silver, Zinc

Bristol Bay region Lake Clark (13.2, 6.6)
60°22'N, 154°29'W

Brecciated zone in Tertiary dacite porphyry; mineralized with pyrite,
pyrrhotite, chalcopyrite, galena, and sphalerite; silver reported.

(Pass Cr.) Gold

Bristol Bay region Lake Clark (11.2, 13.2)
MF-378, loc. 8 60°45'N, 154°41'W

Has been some ground sluicing. Coarse gold reported. Tributary of Bonanza
Cr. See also (Bonanza Cr.)

(Portage Cr.) Gold
Bristol Bay region Lake Clark (17.0, 6.55-6.7)
MF-378, loc. 9 60922'N, 154°03'W

Phyllite, slate, argillite, and greenschist intruded by granitic pluton,
which formed contact aureole a few meters wide. Creek is actively down-
cutting; all gravel deposits postglacial. Most placer mining in canyon
upstream from a fan being rapidly built into Lake Clark. All deposits above
fan contain many large boulders. Both low bench and stream-bar placers.
Considerable barite in some pan-concentrate samples. Intermittent mining
above fan since before 1909. Total production not known, but probably not
more than 1,000 fine oz of gold.

(Ptarmigan Cr.) Gold
Bristol Bay region Lake Clark (13.5, 12.75) approx.

60°43 'N, 154°25'W approx.

Encouraging results from prospecting for placer gold reported. Deposits
probably have lower potential than those of Bonanza Cr.

(Scynneva Cr.) Gold
Bristol Bay region Lake Clark (11.15, 12.45)
MF-378, loc. 7 60°42'N, 154°42'W

Tributary of Bonanza Cr. from which one man mined gold worth about $1,200
from 800-900 yd> of gravel. Large boulders; claims were abandoned. In-
cludes reference to (Scenneva Cr.). See also (Bonanza Cr.).

(Tazimina) : Copper(?)
Bristol Bay region Lake Clark (18.3, 1.7) approx.

60°05'N, 153°55'W approx.

Al2


contains accessory fluorite. A float boulder of altered granite consisted
chiefly of quartz, sericite, kaolinite, albite, and less than 5% dissemin-
ated galena and sphalerite. Other pieces of float contained thin veinlets
of quartz, galena, sphalerite, arsenopyrite, and chalcopyrite and a 1-in-

wide quartz-molybdenite vein. Sediment samples from streams draining the

area contain high contents of Ag, As, Cu, Pb, and Zn.

(Necons R.) Gold

Aniak district Lime Hills (17.0, 1.7) approx.
61°02'N, 154°00'W approx.

Has been recent placer gold activity along and near the Necons R.

(Pass Lake) Copper, Molybdenum, Zinc
Redoubt district Lime Hills (23.2, 17.5) approx.

61°24'N, 153°14'W approx.

Low-grade mineral deposits associated with Tertiary granite contain molyb-
denite, pyrite, pyrrhotite, and some chalcopyrite and sphalerite.

(Styx R.) Gold, Lead, Zinc
McGrath district Lime Hills
MF-412, loc. 14 (in part) EXNE% quad.

Placer gold present in lower basin, but not found in minable quantities.
Altered Tertiary graniteat 61°32'N, 153°09'W (MF-412, loc. 14) contains
small amounts (generally less than 1%) sulfide minerals (pyrite, sphaler-
ite, and galena) as disseminations, in thin veinlets, and in thin quartz
veins.

(Two Lakes) Copper, Molybdenum
Redoubt district Lime Hills (21.9, 1.9) approx.

61°05'N, 153°25'W approx.

Molybdenite and copper minerals associated with Tertiary rhyolite plugs
and flows.

(West Chilligan) Copper, Lead, Molybdenum, Zinc
Redoubt district Lime Hills (23.0, 8.7) approx.

61°28'N, 153°15'W approx.

Mainly porphyry-type deposits related to Tertiary plutons that intruded
older granitic rocks. Deposits contain pyrite, chalcopyrite, molybdenite,
and some galena and sphalerite.

ALS