. t4-~ 7 

~urficial Geologic History 

of the Canyon Village 

Quadrangle, Yellowstone 

National Park, Wyoming, 

for use with Map 1-652 

By GERALD M. RICHMOND 

GEOLOGICAL SURVEY BULLETIN 

A summary of the glacial and nonglacial history of the 

basin ofYellowstone Lake and the Grand Canyon of the 

Yellowstone in the Yellowstone caldera 

1427 

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON: 1976 

\ 
UNITED STATES DEPARTMENT OF THE INTERIOR 

THOMAS S. KLEPPE, Secretary 

GEOLOGICAL SURVEY 

V. E. McKelvey, Director 

Library of Congress Cataloging in Publication Data 

Richmond, Gerald Martin, 1914-

Surficial geologic history of the Canyon Village quadrangle, Yellowstone National Park, 

Wyoming. 

(Geological Survey Bulletin 1427) 

Bibliography: p. 

Supt. of Docs. no.: I 19.3:1427 

1. Geology, Stratigraphic-Quaternary. 2. Geology-Yellowstone National Park. 

I. Title. II. Series: United States Geological Survey Bulletin 1427. 

QE75.B9 no. 1427 [QE696] 557.3'08s (551.4'09787'52] 76-608357 

For sale by the Superintendent of Documents, U.S. Government Printing Office 

Washington, D.C. 20402 

Stock Number 024-001-02899-9 
CONTENTS 

Page 

Units of measure used in this report ............................................................................. III 

Abstract ..................................................................................................................... I 

Introduction ...................................... .. I 

Quaternary history ............ . .. ............................. 2 

Pre-Sacagawea Ridge Glaciation events ................................ . .. ................. 5 

Sacagawea Ridge Glaciation....................................... ......................... 8 

Sacagawea Ridge-Bull Lake interglaciation .... ....................... 9 

Bull Lake Glaciation .......... ................... .. ........................................................... 10 

Early stade ......................... .. ........................................................ 11 

Intra-Bull Lake interstadial ............................... 13 

Late stade .............................. . ................. 15 

Bull Lake-Pinedale interglaciation .. ............. 18 

Pinedale Glaciation .......................... .. ........... 20 

Stagnation of the Pinedale icecap .................. . .. ........... 22 

Postglacial history of the Grand Canyon of the Yellowstone .. 

Postglacial history of Yellowstone Lake 

... 29 

.................. 30 

Other postglacial events ............... . .. ............. 32 

Hydrothermal activity...... .. .............. .. .. ................. 33 

Quaternary faulting ........ ........................... 33 

References ................ .. .. ........................ 34 

ILLUSTRATIONS 

Page 

FIGURE l. Index map of Yellowstone National Park, showing location of 

Canyon Village quadrangle and published U.S. Geological 

Survey Miscellaneous Geologic Investigations Maps .. 3 

2. Map of Canyon Village quadrangle showing distribution of 

Quaternary rhyolite flows .................... ........................................ 4 

UNITS OF MEASURE USED IN THIS REPORT 

To convert 

English units 

Feet (ft) 

Miles(mi) .. 

Inches (in.) 

Yards (yd) 

Feet/mile (ft/mi) 

Multiply fry 

..... 0.3048 

.... 1.609 

........ 2.54 

. 9146 

. 1893 

To obtain 

Metric units 

Metres (m). 

Kilometres (km) . 

Centimetres (em) . 

Metres (m) . 

Metres/kilometre (m/km) . 

III 

SURFICIAL GEOLOGIC HISTORY OF 

THE CANYON VILLAGE QUADRANGLE, 

YELLOWSTONE NATIONAL PARK, 

WYOMING 

By GERALD M. RICHMOND 

ABSTRACT 

The Canyon Village quadrangle lies in central Yellowstone National Park. It includes 

the northern part of Yellowstone Lake and the spectacular sector of the Grand Canyon 

of the Yellowstone seen by most visitors. The oldest Quaternary event recognized in the 

quadrangle occurred about 600,000 years ago when a large caldera, covering most of the 

quadrangle, collapsed after eruption of vast quantities of tuff. Events prior to the 

Sacagawea Ridge Glaciation include primarily a lake in the caldera and the eruption 

from beneath the lake of a large rhyolite flow. Possible glaciolacustrine deposits but no 

till of the Sacagawea Ridge Glaciation were found in the quadrangle. However, Sacagawea Ridge Till derived from sources in Yellowstone National Park occurs just outside 

the park. During the Sacagawea Ridge-Bull Lake interglaciation, further eruptions of 

rhyolite flows and tuffs in the caldera constructed the present Central Plateau and 

thereby separated the eastern part of the lake from a former outlet to the west. As a 

result, the eastern lake rose, and its overflow to the north initiated erosion of a paleocanyon along the course of the present Grand Canyon of the Yellowstone. The subsequent history of the canyon and of the caldera lake consisted largely of a succession of 

major advances and recessions of Bull Lake and Pinedale glaciers, and eruptions of 

rhyolite flows during both glacial and interglacial or interstadial times. canyon, in this 

quadrangle, was partly filled with lake sediments deposited upstream from ice dams 

during both stades of the Bull Lake Glaciation. A major withdrawal of the ice occurred 

between the early and late stades of the Bull Lake Glaciation and during the Bull 

Lake-Pinedale interglaciation. A major shrinkage of the ice also took place between the 

early and middle stades of the Pinedale Glaciation; final wasting was very rapid and 

occurred between about 13,600 and 12,000 years ago. 

INTRODUCTION 

The Canyon Village quadrangle is in central Yellowstone National 

Park (fig. 1). Yellowstone Lake, in the southern part of the quadrangle, 

is bordered to the east by the foothills of the Absaroka Range which 

trends north across the Pelican Cone quadrangle, adjacent to the east, 

and is underlain by Eocene volcanic rocks. West of the lake, Elephant 

Back Mountain forms the east edge of the Central Plateau which ts 
2 YELLOWSTONE NATIONAL PARK, WYOMING 

chiefly in the Norris Junction quadrangle, adjacent to the west. Pelican 

Creek flows into the north end of Yellowstone Lake from its broad 

valley to the east. A short distance to the west, the Yellowstone River 

flows from the lake northward across an east-trending fault at LeHardys Rapids and along a trench through the rolling terrain of 

Hayden Valley. East of Hayden Valley, a broad, high, broken, domeshaped upland culminates in Stonetop Mountain (altitude 9,042 feet, 

or 2,756 m), the highest point in the quadrangle. North of Hayden 

Valley, the Yellowstone River flows through a narrows and then turns 

sharply northeast across Upper Falls (109 feet or 33m high) and Lower 

Falls (319 ft, or 97 m high) into the Grand Canyon of the Yellowstone 

(750-1,600 ft or 228-488 m deep). The canyon, in this quadrangle, 

cuts across a large rhyolite flow which underlies the hills rising eastward to Broad Creek. The spectacular hues of yellow and red for 

which the canyon is so famous are the result of hydrothermal alteration 

of the rhyolite in the areas below Lower Fklls and Inspiration Point, 

and north of the great elbow in the canyon 2.5 miles (4 km) 

downstream. 

This report was originally planned as part of the text of U.S. Geological Survey Miscellaneous Geologic Investigations Map I-652, Surficial 

geologic map of the Canyon Village quadrangle (Richmond, 1976), 

and its organization parallels that of the surficial geologic history texts 

of other surficial geologic maps of Yellowstone National Park (fig. 1). 

However, the unusually large number of geologic units mapped in this 

quadrangle necessitated a descriptive text of such length that available 

space on the map would not permit inclusion of the surficial geologic 

history. 

This report makes constant reference to places, features and deposits shown on map I-652, as well as to the descriptions of geologic 

units and stratigraphic sections on it. Map I-652 is thus essential to the 

use and understanding of this report. An index map of published 

Miscellaneous Geologic Investigations Maps in the park (fig. 1) and an 

index map of the Canyon Village quadrangle showing the distribution 

of Quaternary rhyolite flows (fig. 2) are included both on map I-652 

and in this report. 

QUATERNARY HISTORY 

Yellowstone National Park was repeatedly glaciated by large icecaps 

during the Quaternary. Volcanic eruptions of rhyolite tuffs and flows 

occurred during both glacial and interglacial times. The Quaternary 

history of this quadrangle involves the sequence of these events. Three 

glaciations are recognized, from oldest to youngest: Sacagawea Ridge, 

Bull Lake, and Pinedale (Richmond, 1965). Evidence for Sacagawea 
45° 

CANYON VILLAGE QUADRANGLE, QUATERNARY HISTORY 3 

GARDINER 

' __} 

I -1- ---~-

TEP~E ! MOUNT MA MMO TH 

CRE~K I HO L MES 1- 641 

·~ I 1- 640 

< ,,... 

1~1 WE ST::SI MADI SON NORRI S 

YELLOW STON E J U NCT I ON JUN CT IO N 

1- 648 1'-' 1- 651 1- 650 

, I z 

1 S1 

0 

>< 

I~ 

I I BUFFALO OLD L AKE I 

:ol FAITHFUL 

1~1 1- 649 

I I 

I 

WAR M RIVER GRASS Y LAKE HUCKLEBERRY 

B UTTEj RE SERV OIR MO UNTAIN 

1- 6451 1- 644 1- 6 3 9 

MOUNT 

WALLACE 

MONTAJ:l_,i 

TOWER 

JUNCTION 

1- 647 

MO UNT 

HAN COC K 

1- 636 

( 

------

TW O OCEAN 

PASS 

1- 635 

uo· 

COOKE 

CITY 

44o L_ ____ ~_L--------~--------L_ ______ _L ______ ~ 

0 20 MILES 

0 20 KILOMET RES 

FIGURE 1. - Index map of Yellowstone National Park, showing location of Canyon 

Village quadrangle and published U.S. Geological Survey Miscellaneous Geologic 

Investigations Maps of the area. 

Ridge Glaciation is sparse. Deposits of the Bull Lake Glaciation can be 

divided into informal early and late stades; deposits of the Pinedale 

Glaciation can be divided into informal early and middle stades. Deposits of an informal late stade of the Pinedale have been recognized in 

the Pelican Cone quadrangle (MI-638, Richmond and Waldrop, 1972), 

adjacent to the east. 

K-Ar (potassium-argon) dates determined by John D. Obradovich 

(written commun., 1974, 1975) of rhyolite flows and pumice beds 

stratigraphically related to the sediments broadly place pre-Pinedale 

glacial and interglacial events in time. Carbon-14 dates by Meyer Rubin 
4 YELLOWSTONE NATIONAL PARK, WYOMING 

110°30' 

44°45' 

As 

0 5 Ml LES 

D 5 KILOMETRES 

EXPLANATION 

Rs - Solfatiua Plateau flow 

Rh - Hayden Valley flow 

Re - Elephant Back flow 

Rw - West Thumb flow 

Rdp - Dunraven Pass flow 

Rc - Canyon flow 

Margin of flow 

Inferred position of northwest rim of 600,000-

year-old caldera 

FIGURE 2. - Index map of Canyon Village quadrangle showing distribution of Quaternary rhyolite flows. Modified from "Geologic Map of Yellowstone National Park," U.S. 

Geological Survey Misc. Geol. lnv. Map 1-711, 1972, and "Geologic Map of the 

Canyon Village Quadrangle, Wyoming," U.S. Geol. Survey Geol. Quad. Map GQ1192, 1975. 
CANYON VILLAGE QUADRANGLE, QUATERNARY HISTORY 5 

serve a like purpose for events preceding and following the Pinedale 

Glaciation. 

PRE-SACAGA WEA RIDGE GLACIATION EVENTS 

A large caldera, 30-40 miles (48-64 km) in diameter, developed in 

the park in association with the eruption of a tuff (Boyd, 1961) of the 

Yellowstone Group (Christiansen and Blank, 1972), K-Ar dated as 

about 600,000 years old. The north rim of the caldera extends along 

the base of the Washburn Range, just north of the quadrangle. Broad 

Creek flows along the inside margin of its northeast rim (fig. 2). The 

large faulted elliptical dome east of the Yellowstone River is a resurgent dome underlain by two tuffs of the Yellowstone Group, one about 

600,000 years and the other about 2 m.y. (million years) old (Christiansen and Blank, 1972). 

Subsequent to formation of the caldera, the tuff of Uncle Toms Trail 

(Rut), which is exposed in the Grand Canyon of the Yellowstone 

between Lower Falls and Upper Falls, erupted, probably along the 

fault system just inside the caldera rim to the north. The tuff contains 

the oldest sediments in the caldera, recorded by sand and gravel masses 

several feet long and 1-3 feet (0.3-1 m) thick that are swirled upward 

in the tuff. The sediments were probably swept from a streambed by 

the force of the ash flow that descended the north slope of the caldera 

and formed the welded tuff. Pebbles of quartzite and gneiss in the 

sediments probably were transported by the stream southward from 

Eocene and early Pleistocene or Pliocene conglomerates1 containing 

these rock types that are now exposed north of the caldera rim on the 

southeast slope of Hedges Peak, in the Washburn Range, just north of 

the quadrangle. 

The oldest evidence of a lake in the caldera is the tuffaceous lake silt 

of the sediments of Lower Falls (If) which overlies the tuff of Uncle 

Toms Trail in the wall of the canyon at Lower Falls (stratigraphic 

section 12). The lake rose over the tuff to an altitude of at least 7,650 

feet (2,332 m), the highest altitude at which the lake sediments occur. 

Later, the diamicton of the sediments of Lower Falls was deposited 

over the lake silt. The genesis of this diamicton is not fully understood. 

It has been called till (De Martonne, 1915; Alden, 1928; Richmond, 

1971; U.S. Geological Survey, 1972) and talus (Howard, 1937). The 

1

Schultz ( 1962, p. 43-57) believed these conglomerates and associated sandstones to be all of middle Eocene age on 

the basis of fossil leaves identified by Erling Dorf and the position of some of the beds beneath andesitic volcanic rocks. 

He described some beds as containing chiefly volcanic pebbles and others as chiefly of Precambrian crystalline and 

younger non volcanic rocks. Pollen analysis of silty interbeds in conglomerates composed chiefly of non volcanic rocks, 

exposed at the old Canyon Village water-intake dam along the Dunraven Pass road, revealed types and percentages of 

pollen showing that these particular beds are probably of Pliocene or early Pleistocene age (William Mullenders, 

Louvain Ia Neuve Univ., Belgium, written commun., 1973). The beds at this locality do not underlie andesitic volcanic 

rocks. 
. 6 YELLOWSTONE NATIONAL PARK, WYOMING 

numerous subangular fragments of gray fine-grained biotite diorite in 

it are derived from an Eocene intrusive mass exposed in the area of 

Washburn Hot Springs, just north of the quadrangle (R. L. Christiansen, written commun., 1971). The massive nonbedded unsorted 

tuffaceous nature of the deposit and the shapes of its enclosed fragments suggest that although it may be a till, it more probably is a 

subaqueous tuffaceous mudflow or a subaqueous lithic tuff. It has been 

recognized in boring Y -3 at the picnic area along Yellowstone River 

south of Mud Volcano (Christiansen and Blank, 1975) about 10 miles 

( 16 km) from Washburn Hot Springs. Such extent precludes its being a 

talus. 

There followed an interval of erosion of the caldera wall during 

which the sediments of Lower Falls (lf) were stripped from the tuff of 

Uncle Toms Trail except in the area of the present canyon above 

Lower Falls. The lowest altitude at which evidence of this erosion -

represented by a disconformity between the tuff and the overlying 

Canyon rhyolite flow (Rc) - was observed is 7,500 feet (2,286 m). 

Thus, at the time of erosion, the level of the caldera lake could not have 

been above that altitude. 

The Canyon rhyolite flow (Rc) (K-Ar age about 590,000 years) and 

the associated tuff of Sulphur Creek (Christiansen and Blank, 1972) 

next erupted in the caldera lake in the northeastern part of the quadrangle (fig. 2), locally overlapping onto the north rim of the caldera. 

The upper limit of intense perlitization of the flow, indicative of rapid 

hydration and chilling in contact with water, is at an altitude of about 

7,600 feet (2,316 m) beneath the next younger sediments of Cascade 

Creek (cc) (stratigraphic section 15). This altitude probably approximates that of the caldera lake immediately following eruption of the 

Canyon flow. Other evidence for the existence of the lake at the time of 

the eruption are inclusions of bedded lake silt in the tuff of Sulphur 

Creek along Broad Creek, north of Wapiti Lake Trail. 

At the site of present Lower Falls, the western extremity of the 

Canyon flow encountered a steep prominence, nearly 600 feet ( 183 m) 

high, underlain by the sediments of Lower Falls and the tuff of Uncle 

Toms Trail. A near-vertical contact between the flow and the tuff of 

Uncle Toms Trail is exposed on the east wall of the canyon at Lower 

Falls, and a similarly steep contact between the flow and the diamicton 

of the sediments of Lower Falls is exposed opposite the mouth of 

Cascade Creek (between Lower Falls and Upper Falls), and upstream 

along the east wall of the canyon about 750 yards (686 m) below Upper 

Falls. The prominence divided the rhyolite flow into two lobes which 

flowed around its steep slopes and rejoined to the west in the vicinity of 

the present mouth of Cascade Creek. There, a depression about 100 

feet (30.5 m) deep was left between the two lobes. 
CANYON VILLAGE QUADRANGLE, QUATERNARY HISTORY 7 

Subsequently, the mudflow and alluvial fan facies of the sediments of 

Cascade Creek (cc), composed chiefly of detritus from the Canyon 

flow, were deposited at the west edge of the depression, whereas in the 

depression itself, the tuffaceous lake facies of the sediments of Cascade 

Creek (cc) was deposited. The two facies intertongue abruptly, and 

both rest on the Canyon flow (stratigraphic sections 15, 16). Probably, 

the depression lay at the edge of the caldera lake. The altitude of the 

highest lake sediments (cc) in the depression is 7,600 feet (2,316 m), 

which is about the same as the highest intensely perlitized parts of the 

subjacent Canyon flow. This altitude is about 400 feet ( 122 m) below 

the pre-Grand Canyon drainage divide on the Canyon flow to the 

north, in which direction no similar sediments were found. It is therefore improbable that the caldera lake drained northward at this time. 

More likely, it drained west across the west rim of the caldera near or 

above the site of present Madison Canyon (Madison Junction quadrangle). This hypothesis is based on the probability that the caldera lake 

extended to the west rim ofthe caldera near Madison Junction because 

the rhyolite flows of the Central Plateau were not in existence at this 

time, as discussed below. 

In the northwestern part of the quadrangle, the Dunraven Pass 

rhyolite flow (Rdp) may have erupted over the surface of the Canyon 

flow during deposition of either the sediments of Cascade Creek or the 

sediments of Inspiration Point. However, this is conjecture, inasmuch 

as the flow is not in contact with the sediments and could not be reliably 

K-Ardated. 

Probably after deposition of the sediments of Cascade Creek, but 

possibly at the same time, the sediments of Inspiration Point (ip) were 

deposited at higher altitudes in a broad swale on the surface of the 

Canyon flow along which the canyon itself was subsequently cut. The 

sediments crop out on both rims of the canyon northeast of Cascade 

Creek. Most have been intensely opalized and cemented by hydrothermal solutions (Christiansen and Blank, 1972). Howard ( 1937, p. 

Ill) recognized these highly altered sediments between Grand View 

and Inspiration Point and near Artist Point, but included them with his 

"Rim Sediments" here called the sediments of Upper Falls (uf). Locally, 

they contain layers of chalcedonic sinter, evidence that the sediments 

were deposited near hot springs. The texture and bedding characteristics of the sediments suggest that they are of alluvial and shallow-lake 

origin, much like those forming in Norris Geyser Basin today. Their 

association with sinter at altitudes as low as 7,750 feet (2,362 m) indicates that the caldera lake could not have been that high, for hot 

springs cannot deposit sinter under water (Donald E. White, written 

commun., 1972). Such springs do, however, require a high water table, 

and the caldera lake probably lay to the west and south at about the 

same level as during deposition of the sediments of Cascade Creek. 
8 YELLOWSTONE NATIONAL PARK, WYOMING 

The sinter deposits of hot springs are originally opaline. Their conversion to chalcedony requires subsequent burial for a long time under 

conditions of high temperature and high ground water (White and 

others, 1956). The sinter in the sediments of Inspiration Point may 

have been buried by any of four kinds of deposits or combinations 

thereof. Burial may have been accomplished by additional increments 

of the sediments themselves, by younger pumiceous tuff units described below, by ice-contact deposits or till of the Sacagawea Ridge 

Glaciation localized as a result of rapid melting of the glacier over the 

hot springs area, or by lake sediments of Sacagawea Ridge-Bull Lake 

interglacial age. Whatever the cover, it has now been stripped away by 

erosion. 

Three pumiceous tuff beds exposed in the south wall of the canyon 

below the lookout at Uncle Toms Trail parking area (stratigraphic 

section 13, pumice beds uf-I, uf-11 and uf-III of the sediments of 

Upper Falls, uf) were deposited at some time after deposition of the 

sediments of Inspiration Point. The oldest, pumice bed uf-I, rests 

disconformably on the diamicton of the sediments of Lower Falls. It is 

22 feet (6. 7 m) thick and its top is at an altitude of 7,640 feet (2,329 m). 

The upper 12 feet (3.6 m) of the pumice are stained bright orange by 

iron oxide. The color zone appears related to a long stand of the water 

table rather than to weathering. The source and age of the pumice are 

unknown. Pumice bed uf-11 is about 8 feet (2.4 m) thick. It yielded a 

K-Ar age older than the caldera and, thus, must contain age contaminants. Pumice bed uf-III, about 12 feet (3.6 m) thick, yielded a K-Ar 

age of about 266,000 years. Between pumice beds uf-11 and uf-III at 

stratigraphic section 13 is a pumiceous sandy diamicton (ufd), discussed below. 

SACAGA WEA RIDGE GLACIATION 

Though no distinct till of the Sacagawea Ridge Glaciation was found 

in the quadrangle, Sacagawea Ridge Till immediately south and 

southwest of Yellowstone National Park in the Huckleberry Mountain 

quadrangle (Richmond, 1973b), Grassy Lake Reservoir quadrangle 

(Richmond, 1973c), and Warm River Butte quadrangle (Richmond, 

1973d) was deposited by cap ice flowing from the caldera. Sacagawea 

Ridge ice was therefore probably present in this quadrangle. Just west 

of the park, in the Buffalo Lake quadrangle, reddish, deeply weathered loess beneath a flow K-Ar dated as about 156,000 years old is 

considered to be of Sacagawea Ridge age. An older glacial advance, 

included in the Sacagawea Ridge Glaciation, is represented by a till-like 

diamicton exposed in the shore of Flat Mountain Arm of Yellowstone 

Lake in the Frank Island quadrangle (MI-642, Richmond, 1974). The 

till lies below lake silt that is overlain by a thick pumiceous tuff K-Ar 
CANYON VILLAGE QUADRANGLE, QUATERNARY HISTORY 9 

dated as about 219,000 years old. I correlated the Tuff (Richmond, 

1974) with the Shoshone Lake Tuff member (Christiansen and Blank, 

1972), K-Ar dated as about 155,000 years old, but I now believe that 

the till-like diamicton at Flat Mountain is older than about 219,000 

years. In the Canyon Village quadrangle, the diamicton exposed at 

stratigraphic section 13 between pumice beds uf-II and uf-III of the 

sediments of Upper Falls may represent a correlative deposit. The 

diamicton is a compact, massive, angular pumiceous sand containing 

scattered subangular to subround clasts, chiefly of local derivation but 

including a few quartzite erratics. Its poor sorting and local weak 

lacustrine bedding suggest a glaciolacustrine origin. 

SACAGAWEA RIDGE-BULL LAKE INTERGLACIATION 

Eruption of a succession of rhyolite flows and tuffs within the caldera 

in the Norris Junction (MI-650, Richmond and Waldrop, 1975) and 

West Thumb (MI-643, Richmond, 1973a) quadrangles, west and 

southwest of this quadrangle, took place between about 160,000 and 

about 140,000 years ago, on the basis of K-Ar dating of the flows. 

These eruptions built up the Central Plateau, gradually divided the 

caldera lake into eastern and western parts, and eventually blocked the 

probable former westward drainage of the eastern part. In this quadrangle, the eruptions of the West Thumb rhyolite flow (Rw) (K-Ar age 

about 144,000 years), and of the overlying, slightly zounger Elephant 

Back rhyolite flow (Re) were a late phase of this volcanic activity (fig. 2). 

The West Thumb flow (Rw) erupted eastward across the caldera lake 

basin and impinged against the flank of the faulted resurgent dome 

east of the present Yellowstone River at an altitude of about 8,000 feet 

(2,438 m). It thereby divided the eastern caldera lake into two parts, 

one to the south and one to the north. The southern lake rose to an 

altitude of at least 8,000 feet or 2,438 m (overstated at 8,100 feet or 

2,469 m in Richmond, 1973a, 1974) or about 270 feet (83 m) above 

present Yellowstone Lake. Its outlet was to the north around the outer 

margin of the West Thumb flow in the area of present LeHardys 

Rapids. Deposits of this lake are exposed in the Frank Island quadrangle (Richmond, 197 4), adjacent to the south. 

The northern lake also rose against surrounding divides. Its sediments include the lacustrine pumiceous silty sand exposed in the west 

bluff of the Yellowstone River in Hayden Valley (s-bsl in stratigraphic 

sections 29, 30), and possibly the lowest lake silt (s-bl) of the sediments 

of Upper Falls (uf) downstream from Upper Falls. Its highest sediments (mapped as uf) are at an altitude of 7,900 feet (2,408 m) in the 

southeastern part of Canyon Village. The lake is inferred to have 

attained an altitude of 8,000 feet (2,438 m) and to have been the first to 

drain northward across the divide of the Canyon rhyolite flow (Rc) at 
10 YELLOWSTONE NATIONAL PARK, WYOMING 

about the position of the great elbow in the present canyon 2 miles (3 

km) downstream from Point Sublime. To the north, the outlet stream 

flowed into an ancestral Yellowstone River whose headward erosion to 

the elbow at that time is suggested by the abrupt doubling of the width 

of the present canyon both in the soft hydrothermally altered rock of 

the Canyon flow immediately downstream and in the hard rocks in the 

Tower Junction quadrangle to the north. 

After overflow, the outlet stream cut a narrow canyon about 320 teet 

(97 m) deep from the elbow upstream past Red Rock as far as Lower 

Falls. Fragments of highly altered, silicified sediments derived from the 

sediments of Inspiration Point, well-rounded pebbles of biotite diorite 

derived from the diamicton of the sediments of Lower Falls upstream, 

and well-rounded pebbles of andesite derived from either upstream or 

downstream occur in the talus breccia at the base of the sediments of 

Red Rock (rr) (stratigraphic section 8). They show that the canyon was 

cut through both the sediments of Inspiration Point (ip) and the 

diamicton of the sediments of Lower Falls (lf) into the underlying 

Canyon rhyolite flow (Rc). This canyon lay entirely within the area of 

the present canyon. A remnant of it, now a paleocanyon filled with the 

sediments of Red Rock (rr), is preserved between Red Rock, a pinnacle 

jutting from the west wall of the present canyon, and the main canyon 

wall Qones and Field, 1929; Howard, 1937). At Red Rock, the base of 

the paleocanyon is at an altitude of about 7,400 feet (2,255 m), 250 feet 

(76 m) above the present canyon floor and about 80 feet (24 m) below 

the present top of Lower Falls. An ancestral Lower Falls may therefore 

have existed at the head of the paleocanyon. If so, its crest was probably 

at an altitude of about 7,800 feet (2,377 m), and its height above the 

floor of the paleocanyon was probably between 350 and 400 feet ( 106 

and 122m). This ancestral falls would have been retained, as today, by 

a zone of hard rhyolite at the outer margin of the Canyon flow, in 

near-vertical contact with the tuff of Uncle Toms Trail (Rut) upstream. 

Upper Falls did not exist at that time. 

BULL LAKE GLACIATION 

The Bull Lake Glaciation in Yellowstone National Park comprised 

two stades of widespread icecap development, separated by an interval 

when the ice retreated from both Hayden Valley and the basin of 

Yellowstone Lake. During both stades, valley glaciers flowed west and 

north from the Absaroka Range into the basin of Yellowstone Lake 

where they merged as a single icecap. At their maximums, the icecaps 

of both stades were more than 3,000 feet (915 m) thick and extended 

south and west of this quadrangle to points within and beyond the 

boundaries of the park. North of the quadrangle the ice merged with 

another large glacier in the drainage of the Lamar River. 
CANYON VILLAGE QUADRANGLE, QUATERNARY HISTORY 11 

EARLY STADE 

Glacial sediments here assigned to the early stade of the Bull Lake 

Glaciation are distinguished in stratigraphic sections of the sediments 

of Upper Falls (uf). In Hayden Valley (stratigraphic sections 29, 30) 

and in the area of the canyon (stratigraphic section 13), they consist of a 

thin layer of unsorted subangular to subround pebbles and cobbles in a 

silty sandy matrix (bgl) and contain erratics of basalt and andesite from 

the Absaroka Range. In the headwaters of Astringent Creek (stratigraphic section 55), they are composed of rhyolite, tuff, andesite, and 

basalt, are 30 feet (9 ni) thick, and probably represent an outwash or 

ice-contact deposit, Locally (stratigraphic sections 29, 30), they overlie 

coarse gravelly lake sand (bsll) of possible proglacial origin; elsewhere 

(stratigraphic sections 13) they rest disconformably on laminated lake 

silt (s-bl) of the Sacagawea Ridge-Bull Lake interglacial interval. In the 

Frank Island quadrangle (MI-642, Richmond, 1974) lake silt of the 

Sacagawea Ridge-Bull Lake interglaciation is extensively exposed in 

the bluffs of Yellowstone Lake, locally beneath Bull Lake Till (bt). The 

silt contains a pumice bed K-Ar dated about 150,000 years old, and 

rests on the West Thumb rhyolite flow, more reliably K-Ar dated as 

about 144,000 years old. The early stade of the Bull Lake Glaciation is 

thus younger than about 144,000 years. In the Madison Junction 

quadrangle (MI-651, Waldrop and Pierce, 1975), Waldrop found 

erratics of basalt above and beyond the outer limit of Pinedale end 

moraines and 1,200 feet (365 rn) above the nearby valley of the Madison River on the steep west-facing slope of the West Yellowstone 

rhyolite flow, K-Ar dated as 114,500±7,300 years old. Abnormal incurving basins along the margin of this flow indicate that it erupted 

around and in contact with something no longer there, and suggests to 

R. L. Christiansen (written commun., 1974) and myself that the flow 

erupted in contact with a glacier. The basalt erratics could only have 

been deposited at this time for they lie beyond the outer limits of 

Pinedale ice. I infer that they were deposited during the early stade of 

the Bull Lake Glaciation, for they are younger than deposits between 

150,000 and 160,000 years old, correlated with the Sacagawea Ridge 

Glaciation. Presumably, deposition of these deposits was separated 

from that of the erratics by the interglaciation about 125,000 years ago 

that is widely recognized in other parts of the world. 

In this quadrangle (stratigraphic sections 13, 30), glacial sediments 

(bgl) of the early stade of the Bull Lake are locally overlain by lacustrine 

gravelly sand (bsll), possibly related to the recession of early Bull Lake 

ice. Above this sand and directly above the glacial sediments elsewhere 

(stratigraphic section 29) are laminated lake silts (bil). In Hayden Valley (stratigraphic sections 18, 19, 29, 30), these silts are invaded by the 

Hayden Valley rhyolite flow (Rh) (K-Ar age about 100,000 years; fig. 

2). In the canyon area the lake silts are overlain by lake sand containing 
12 YELLOWSTONENATIONALPARK, WYOMING 

a pumice bed K-Ar dated as about 99,000 years old (near stratigraphic 

section 13). The early stade of the Bull Lake Glaciation is thus older 

than about 99,000 or 100,000 years by an undetermined amount of 

time, the time of existence of this lake. I estimate that it began about 

120,000 years ago and ended about 110,000 years ago. 

Erratics of basalt and andesite from the Absaroka Range in glacial 

sediments of early Bull Lake age (stratigraphic sections 13, 29, 30) 

show that the ice advanced across the quadrangle from the southeast. 

In and north of Hayden Valley the ice flowed across older lake beds of 

the Sacagawea Ridge-Bull Lake interglacial interval (stratigraphic sections 29, 30). Beyond, to the west and north, it thickened against and 

probably overrode the divides of the Central Plateau and the 

Washburn Range. While this ice was advancing from the southeast, a 

large glacier was also developing in the drainage of the Lamar River, 

which is tributary to the Yellowstone River in the northern part of the 

park (Alden, 1928; Howard, 1937; Pierce, 1974). Lateral extension of 

this ice to the south was proposed by Howard (1937) as a means of 

impounding the lacustrine sediments of Red Rock (rr) in the paleocanyon of the Yellowstone River in this quadrangle. This hypothesis is 

still the most acceptable. One or more landslides downstream from Red 

Rock could have formed temporary dams as they have at later times, 

but such dams would hardly have lasted for sufficient time to permit 

deposition of over 200 feet (61 m) of the sediments of Red Rock. 

Movement along faults that cross the canyon downstream from Red 

Rock might have formed dams, but the precise age and extent of 

displacement of the faults are unknown. 

The sediments of Red Rock (rr) have an original northeasterly 

downstream dip and in places a downstream deltaic structure. They 

were therefore derived from the south. None are varved and none 

contain erratics. This suggests that the ice both to the north and to the 

south was probably at a distance. Overflow of the lake across the ice to 

the north was at an altitude of at least 7,585 feet (2 ,312 m), the present 

top of the sediments, and probably higher. The sediments are believed 

to have been deposited during the advance of the early Bull Lake 

glaciers, rather than during their recession, because they rest on a talus 

breccia containing river gravel and sand (stratigraphic section 8), 

rather than on till. Pebbles of andesite and biotite diorite in the gravel 

could have been derived from sources to either north or south, but the 

fact that the gravel is well rounded indicates that it was transported 

from southern sources by the north-flowing ancestral Yellowstone 

River. I infer that after the sediments of Red Rock were deposited, they 

were overridden by early Bull Lake ice from the south because no 

erratics of northern derivation have been found in deposits of early 

Bull Lake age in this quadrangle. 
CANYON VILLAGE QUADRANGLE, QUATERNARY HISTORY 13 

Deposits associated with the recession of early Bull Lake ice include 

the gravelly sand (bsll) and silt (bll) immediately above the erraticbearing glacial sediments (bgl) at stratigraphic section 13 and elsewhere 

just below the canyon rim (stratigraphic sections 9, 10, 14) at an altitude 

of about 7,900 feet (2,410 m). Along the highway, just south of the 

parking area at Artist Point (stratigraphic section 9), the sand is overlain by varved silt. These sediments therefore were deposited in a lake 

retained at an altitude of 7,900-8,000 feet (2,410-2,438 m) over the 

hydrothermally active section of the paleocanyon by ice of northern 

derivation northeast of Inspiration Point. The lake was probably short 

lived. 

A similarly short-lived but smaller lake existed over a hydrothermally 

active area in the headwaters of Astringent Creek in the east-central 

part of the quadrangle. It was impounded between ice to the south and 

the Astringent Creek-Broad Creek divide to the north, over which it 

probably drained at an altitude of about 8,200 feet (2,500 m). At 

stratigraphic section 55, gravel (bgl) of early Bull Lake age is overlain 

by sand deposits (bsll) of the lake, beneath younger deposits oflate Bull 

Lake and Pinedale age. 

INTRA-BULL LAKE INTERSTADIAL 

Following stagnation and recession of the early Bull Lake icecap, the 

Yellowstone River began to cut a new canyon below Lower Falls 

through the sediments of Upper Falls (uf, stratigraphic section 9, units 

bll and older) and the sediments of Red Rock (rr) into the underlying 

Canyon rhyolite flow (Rc). Lower Falls was probably exhumed. The 

course of this new canyon was within the limits of the present canyon. 

At the end of the interval, its depth may have been about 280 feet (85 

m) at Inspiration Point, south of which a segment of its floor is preserved on the west wall of the canyon beneath sediments inferred to be 

of late Bull Lake age (gv, stratigraphic section 5). 

Above Lower Falls, an open lake extended southwest and south 

across Hayden Valley. The highest deposits of this lake are cemented 

nearshore sands of the sediments of Upper Falls (uf) that are exposed 

around the hills south of the canyon at altitudes between 7,760-7,800 

feet (2,365-2,377 m). In the Norris Junction quadrangle (MI-650, 

Richmond and Waldrop, 1975), along the upper part of the canyon of 

Cascade Creek at an altitude of 7,800 feet (2,377 m), some of these 

sands were injected into the base of, and were baked by, the overlying 

Hayden Valley rhyolite flow (Rh) (K-Ar age about 100,000 years). I 

infer that the lake was retained at this level by a dam formed of the 

nearly vertical hard rhyolite at the margin of the Canyon rhyolite flow 

(Rc) at the present position of Lower Falls. In Hayden Valley, as has 

been stated, massive and laminated offshore silt deposits (bil in strati-
14 YELLOWSTONE NATIONAL PARK, WYOMING 

graphic sections 29, 30) of this lake locally overlie deposits of early Bull 

Lake age and underlie the Hayden Valley flow (Rh). The silt contains 

abundant pumice from the flow and is infolded into its lower part. 

Along the east side of the Yellowstone River (stratigraphic sections 18 

and 19), the silt also was injected as much as 40 feet (12m) up into the 

flow by its overriding weight. At the highway bend just south of 

Chittenden Bridge (Norris Junction quadrangle; MI-650, Richmond 

and Waldrop, 1975), a great fold of the silt extending up into the 

overlying perlitized flow is well exposed. In the canyon between Upper 

and Lower Falls, the silt (bil) and overlying pebbly sand (bslu) (the "Rim 

Conglomerate" of Howard, 193 7, p. 11 0) are exposed along and below 

both rims (stratigraphic sections 13, 14). They form the uppermost 

part of the sediments of Upper Falls (uf). The upper part of the sand is 

extremely rich in pumice and obsidian. A pumice layer near its top 

yielded a K-Ar age of about 99,000 years and is probably related to the 

eruption of the Hayden Valley rhyolite flow, K-Ar dated at about 

100,000 years. Intrusion of the Hayden Valley flow into the lake 

displaced its waters from Hayden Valley and the area northward to 

about the site of present Upper Falls. Displacement of the water may 

well have caused catastrophic erosion of the canyon downstream. 

The Hayden Valley flow extended east of the present Yellowstone 

River (fig. 2). West of the river in the Norris Junction quadrangle 

(MI-650, Richmond and Waldrop, 1975), it extended north of the 

present site of Upper Falls. Outcrops of the flow overlying lake sand 

(uf, unit bsll) of early Bull Lake age occur within 220 yards (200 m) of 

Upper Falls. They suggest that the flow extended to the site of the falls 

and that it controlled their original position, now controlled by hard 

rhyolite at the north edge of a lobe of the Canyon rhyolite flow (Rc). 

Following eruption of the Hayden Valley rhyolite flow, a low-level lake, 

dammed by the flow, probably existed in Hayden Valley. From it, the 

ancestral Yellowstone River drained across the flow to the present 

confluence of Otter Creek (Norris Junction quadrangle). Beyond, it 

flowed along the margin of the Hayden Valley flow to Upper Falls 

which first came into existence at this time. Subsequently, the river cut 

a channel at least 50 feet (15m) deep across the flow before eruption of 

the Solfatara rhyolite flow (Rs). 

A lake also existed in the basin of Yellowstone Lake during the 

intra-Bull Lake interstadial. In this quadrangle, its sediments were 

found only at Steamboat Point (bisl, bil, stratigraphic section 65), where 

they underlie till of late Bull Lake age and younger deposits. The lake 

was impounded in the area of LeHardys Rapids, as was its predecessor 

during the Sacagawea Ridge-Bull Lake interglaciation, by the east 

margin ofthe West Thumb rhyolite flow (Rw), where it overlapped the 

flank of the dome of older tuffs of the Yellowstone Group to the east. 

The surface of the lake, as thus controlled, was probably at an altitude 
CANYON VILLAGE QUADRANGLE, QUATERNARY HISTORY 15 

of about 7,980-8,000 feet (2,432-2,438 m). Its outlet was northward 

across the dam into the lake in Hayden Valley. That this lake was an 

extensive open lake is substantiated by the presence of lake silt containing a layer of pumice, K-Ar dated as about 103,000 years old, along 

Chipmunk Creek at the south end of Yellowstone Lake. Open water in 

that area must indicate withdrawal of the ice for climatic reasons. 

Neither rhyolite extrusion of this age nor hydrothermal activity capable of inducing local melting occurs in that area. However, glaciers may 

have existed in the Absaroka Range and in the valley of the Yellowstone River south of Yellowstone National Park. 

LATE STADE 

The icecap of the late stade of the Bull Lake Glaciation advanced 

from the southeast in the same manner as that of the early stade. 

Nowhere in the quadrangle were erratics of northern derivation, such 

as granite, gneiss, or quartzite, found in deposits of late Bull Lake age. 

However, while late Bull Lake ice was advancing from the southeast, 

another icecap developed in a drainage basin tributary to the Yellowstone River in the northern part of the park (Tower Junction 

quadrangle, MI-647, Pierce, 1974). Lateral buildup ofthis ice from the 

north is inferred to have impounded a lake west of Inspiration Point in 

the canyon existing at that time. Lake sediments derived from the 

south were deposited in this lake and are now exposed (stratigraphic 

section 5) beneath a younger landslide deposit on the northwest wall of 

the present canyon 0.4 mile (0.6 km) northeast of Grand View, from 

which their informal name, sediments of Grand View, is derived. 

The sediments of Grand View (gv) are about 150 feet (45 m) thick. 

They consist of sand rich in obsidian and pumice, and varved silt. The 

obsidian and pumice were probably derived from the Hayden Valley 

flow (Rh) upstream. Their abundance is in marked contrast to their 

near absence in the sediments of Red Rock (rr) of early Bull Lake age 

and is a major reason for assigning them a late Bull Lake age. The base 

of the deposits is about 380 feet (115 m) below the rim of the canyon at 

Inspiration Point, a measure of the depth of the canyon in late Bull 

Lake time. These sediments were probably deposited during the advance of late Bull Lake ice from the north because they overlie talus 

rather than till. Following deposition, they are believed to have been 

overridden by ice from the south because of the absence of erratics 

from the north in deposits of late Bull Lake age in this quadrangle. The 

southern ice probably merged with the northern ice north of the 

quadrangle. However, no till or erratics were found between the sediments and the overlying landslide deposit. 

Elsewhere in the quadrangle, till (bt) and glacial rubble (br) of late 

Bull Lake age occur on the higher part of the upland east of the 

canyon. They are mapped as late Bull Lake because they lie topo-
16 YELLOWSTONE NATIONAL PARK, WYOMING 

graphically higher than thick, hummocky Pinedale moraines to the 

west. The deposits contain erratics of Eocene basalt and andesite. 

Basalt erratics in the till have weathering rinds as much as one-fourth 

inch (0.6 em) thick, and the profile of weathering on the till is locally 

24-30 inches (60-75 em) thick, in contrast to less than 12 inches (30 em) 

on Pinedale Till. 

Glacial sediments referred to the late stade of the Bull Lake Glaciation can be stratigraphically bracketed and restricted in age. At Steamboat Point (stratigraphic section 65) till (btu) and interlayered gravel, 

both containing erratics of Eocene basalt, andesite, and rhyodacite 

porphyry, overlie lake deposits of the intra-Bull Lake interstadial (bil, 

bisl) and are overlain by pumice-bearing lake silt and sand (bsl) of 

either late Bull Lake age or Bull Lake-Pinedale interglacial age. These 

units are steeply overlapped by Pinedale Till and kame gravel. In 

Hayden Valley (stratigraphic sections 29,30), sandy gravel (bgu) containing striated erratic cobbles of basalt and andesite overlies the 

Hayden Valley rhyolite flow (K-Ar age about 100,000 years); the gravel 

grades up into lake silt of late Bull Lake age which is overlain disconformably by Pinedale Till. Farther west in Hayden Valley, in the Norris 

Junction quadrangle (MI-650, Richmond and Waldrop, 1975), till, 

containing erratics of basalt and andesite, overlies the Hayden Valley 

flow and grades upward into varved silt of late Bull Lake age which is 

overlain disconformably by Pinedale Till. Between Upper Falls and 

Lower Falls (stratigraphic sections 11, 12, 14), sandy gravel containing 

subangular clasts and erratics of basalt and andesite disconformably 

overlies the cemented upper sand (bslu) of the sediments of Upper 

Falls. The sand contains a pumice bed K-Ar dated as about 99,000 

years old whose eruption is probably related to that 'of the Hayden 

Valley flow (Rh). At a nearby temporary excavation (stratigraphic 

section 11), the zone of erratic-bearing gravel grades upward into 

pumice-rich silt that contains a layer of clean pumice and is overlain by 

sorted well-bedded sand. The sand is overlain by construction debris at 

this exposure, but nearby it is overlain by Pinedale Till containing 

erratics of granite and gneiss from the north. The lake deposits above 

the zone of erratics probably accumulated rapidly in an ice-dammed 

lake. The pumice is as yet undated. It is inferred to be associated with 

the eruption of the Solfatara Plateau rhyolite flow (Rs) (fig. 2), which 

yielded a K-Ar age of about 107,000 years but which overlies the 

Hayden Valley rhyolite flow (Rh) K-Ar dated at about 100,000 years. 

In the Norris Junction quadrangle (MI-650, Richmond and Waldrop, 

1975), adjacent to the west, the incurvate shape of the Solfatara Plateau 

flow, the shattered and recemented nature of its glassy marginal breccia, and the intimate association of the breccia with glass-rich sediments 

of late Bull Lake age (sediments of Otter Creek, not exposed in this 

quadrangle) indicate that the flow probably erupted against advancing 
CANYON VILLAGE QUADRANGLE, QUATERNARY HISTORY 17 

late Bull Lake ice. The zone of erratics and overlying pumice-bearing 

lake sediments at stratigraphic section 11 may have been deposited at 

this time. 

In the western part of the Norris Junction quadrangle, the Gibbon 

River rhyolite flow, K-Ar dated as about 88,000 years old, was not 

glaciated by late Bull Lake ice, although it lies in the path of the ice and 

below its upper limit. However, the flow dammed a lake whose northern end was dammed by late Bull Lake ice from the north (MI-650, 

Richmond and Waldrop, 1975). The late Bull Lake glacial advance 

therefore began at some time after extrusion of the Hayden Valley 

flow about 100,000 years ago. I infer that it began about 98,000 years 

ago and that the Solfatara Plateau rhyolite flow (Rs) erupted against 

the ice about 95,000 years ago. The glacier had receded east of the 

western part of the Norris Junction quadrangle, but still lay to the 

north, about 88,000 years ago. Deglaciation was completed by 85,000 

years ago. The total duration of the late stade of the Bull Lake Glaciation may therefore have been about 13,000 years, which is essentially 

the same as the duration of the last glaciation (late Wisconsin) as dated 

in other parts of the United States. 

During late Bull Lake deglaciation, large mounds of kame gravel 

(bkg, bksg) were deposited beneath or adjacent to the ice in areas of 

hydrothermal activity, owing to more rapid melting of the ice in these 

areas. The deposits, now hydrothermally altered and silica cemented, 

are partly overlapped by uncemented Pinedale Till or ice-contact deposits. They occur in Hayden Valley, south of Artist Point, at Josephs 

Coat Springs and on Sulphur Hills. 

As deglaciation progressed, a lake opened in Hay<;len Valley. The 

silty sediments of the lake (bl) are mostly varved but in places are 

massive or laminated. They are commonly mantled by Pinedale Till or 

by erratics that, north of Crater Hills, include granite and gneiss of 

northern derivation. Beneath the till, the lake beds are locally disrupted, broken, and mixed with masses of the till throughout a zone a 

few feet thick. However, no erratics of northern derivation were found 

in the lake beds themselves. East of Yellowstone River the silt .occurs at 

a maximum altitude of 8,120 feet (2,475 m). To the south, on both 

sides of the river in the area of Mud Volcano, the silt is as much as 

7,960 feet (2,426 m) high. In the central part of the valley, it underlies 

ridges at about 7,940 feet (2,420 m). This distribution suggests that 

deposition began in high ice-marginal ponds, which gradually expanded and merged to become an open lake. Howard (1937, p. 94) 

inferred that the lake sediments comprised deposits of a proglacial 

"advance" phase overlain by deposits of a "retreat" phase of his 

"Hayden Lake," dammed during both phases by ice from the north. 

However, he was unable to demonstrate evidence of glaciation between 

the lake deposits. He concluded that these lakes were associated with 
18 YELLOWSTONE NATIONAL PARK, WYOMING 

the last glaciation (Pinedale). Because the lake deposits contain no 

erratics of northern origin, grade downward into till of late Bull Lake 

age containing erratics of southeastern origin, and, in the Norris J unction quadrangle (MI-650, Richmond and Waldrop, 1975), are crumpled, folded, and mixed beneath overlying Pinedale Till containing 

erratics of northern origin, I conclude that they were deposited during 

wasting of late Bull Lake ice. 

North of Hayden Valley, the varved silt (bl) overlaps the slopes of the 

Solfatara Plateau flow (Rs) to an altitude of 8,080 feet (2,463 m) and is 

at about the same altitude northwest and southeast of the canyon 

where it is extensively overlain by Pinedale TilL Along the road just 

south of Artist Point (stratigraphic section 9), the varved silt (bl) overlies cemented and hydrothermally altered sediments of Upper Falls 

(uf). The lake must therefore have been dammed at an altitude of over 

8,000 feet (2,438 m) by ice in and over the canyon, as postulated by 

Howard (1937), though in late Bull Lake time rather than during the 

Pinedale advance. 

At about the same time that the lake existed in Hayden Valley, a lake 

was opening around stagnant ice in the basin of Yellowstone Lake. Its 

highest deposits (bsl, stratigraphic section 55), in the headwaters of 

Astringent Creek, consist of hydrothermally altered lake sand that rests 

on glacial gravel (bgu) oflate Bull Lake age which overlies more altered 

deposits of early Bull Lake age. The lake sand (bsl) is overlain by 

unaltered kame sand (pks) of Pinedale age. The deposits lie 520 feet 

(158m) above present Yellowstone Lake. Their position, 50 feet (15m) 

above the divide to the north, suggests that the lake was dammed by ice 

both to the north and to the south. Varved silt (bl), overlapped by 

Pinedale Till just west of Natural Bridge and 320 feet (97 m) above 

Yellowstone Lake, may represent the locus of an ice-marginal pond. 

One or more floods may have taken place during final disintegration 

of late Bull Lake ice. Such floods may have initiated erosion of the 

trench of the Yellowstone River through Hayden Valley and of the 

present Grand Canyon of the Yellowstone in the sediments of Grand 

View (gv). 

BULL LAKE-PINEDALE INTERGLACIATION 

During the Bull Lake-Pinedale interglaciation, as during previous 

interglacial intervals, a high-level open lake was impounded in the 

basin of Yellowstone Lake by a dam in the area where the West Thumb 

rhyolite flow (Rw) overlaps the dome of older tuffs near present 

LeHardys Rapids. Though the surface altitude of this lake cannot be 

determined in this quadrangle, huge silt deltas, overlain by Pinedale 

Till and gravel in the valley of the Yellowstone River and its tributaries 
CANYON VILLAGE QUADRANGLE, QUATERNARY HISTORY 19 

south of Yellowstone Lake, are at an altitude of7,980 feet (2,432 m) or 

250 feet (76 m) above present Yellowstone Lake, in the Eagle Peak 

(MI-637, Richmond and Pierce, 1972), Two Ocean Pass (MI-635, 

Richmond and Pierce, 1971), and Frank Island (MI-642, Richmond, 

1974) quadrangles. The silt deposits locally overlie a thin volcanic ash 

at the top of a compressed peat that rests on thick, weathered outwash 

gravel of late Bull Lake age. The ash has petrographic characteristics 

indicating a source within Yellowstone National Park (R. E. Wilcox, 

oral commun., 1972) and can therefore be no younger than about 

70,000 years, the K-Ar age of the youngest rhyolite flow in the park. 

Wood from the middle part of the delta deposits yielded a radiocarbon 

age of >42,000 years (W-2197) and >45,000 years (W-2411, Meyer 

Rubin, written commun., 1970). 

In this quadrangle, silt (pbl) and sand (pbsl) deposits of the lake are 

exposed in several places in the bluffs of present Yellowstone Lake. At 

Lake Hotel (stratigraphic section 80), they lie beneath Pinedale Till; at 

Fishing Bridge (stratigraphic sections 78, 79) they contain a layer of 

volcanic ash and underlie Pinedale lake deposits (pl, psl); at Steamboat 

Point (stratigraphic section 65), they contain a pumice-rich sand, overlie till and gravel of late Bull Lake age, and are overlain by ice-contact 

gravel of Pinedale age. Exposures of the silt along Sedge Creek are 

capped by Pinedale Till; others in Pelican Valley are overlain by 

Pinedale erratics of Eocene volcanic rocks. Along Bear Creek near 

Turbid Lake (stratigraphic sections 58, 59), a gravelly sand (pbgl) 

facies is overlain by Pinedale Till and younger deposits. 

Drainage from the lake across the dam at LeHardys Rapids probably 

further deepened and widened the trench of the Yellowstone River 

through Hayden Valley. At some time during the interglaciation a 

shallow lake lay within the trench at an altitude of about 7,760 feet 

(2,365 m). At the great southward bend of Sour Creek, a deposit of 

cemented gravelly sand (bdgs), having long foreset bedding, represents 

a delta in this lake. The cemented delta deposits have been truncated, 

probably by Pinedale ice, and are overlapped by similar but uncemented Pinedale delta deposits (pdgs). No deposits of this lake occur 

along the Yellowstone River north of Hayden Valley, which suggests 

that the lake was dammed where the east margin of the Solfatara 

Plateau flow (Rs) overlapped the Hayden Valley flow (Rh) (fig. 2). To 

the north, the ancestral Yellowstone River deepened its valley as far as 

Lower Falls. Downstream, by the end of the Bull Lake-Pinedale interglaciation, the river had cut a canyon about 440 feet (135 m) deep 

through the sediments of Grand View, west of Inspiration Point 

(stratigraphic section 5), into the underlying Canyon flow (Rc). At the 

north edge of the quadrangle, this canyon was cut deeper than the bed 

of the present river. 
20 YELLOWSTONE NATIONAL PARK, WYOMING 

PINEDALE GLACIATION 

Early in Pinedale time, glaciers formed in the higher parts of the 

Absaroka Range east and southeast of Yellowstone Lake. The glaciers 

flowed into the lake basin where they coalesced to become a large 

icecap (Richmond and Pierce, 1972). The cap eventually attained a 

thickness of about 3,000 feet (915 m) in the southeastern part of the 

lake basin (Frank Island quadrangle; MI-642, Richmond, 1974) and 

may have been as much as 2,000 feet (610 m) thick in the southeastern 

part of this quadrangle. The beginning of Pinedale time cannot be 

precisely dated. In the Frank Island (MI-642, Richmond, 1974) and 

Eagle Peak (MI-637, Richmond and Pierce, 1972) quadrangles, 

Pinedale Till and ice-contact deposits disconformably overlie lake silt of 

the Bull Lake-Pinedale interglaciation that contains wood more than 

40,000 years old and locally overlies volcanic ash not less than about 

70,000 years old. 

In this quadrangle, Pinedale Till overlies lake deposits of the Bull 

Lake-Pinedale interglaciation in the bluffs of Yellowstone Lake at a 

number of places (stratigraphic sections 64, 80, 81, and elsewhere). 

Erratics of Eocene basalt, andesite, and volcanic breccia in the till north 

and west of the lake show that the ice flowed northwestward across the 

southern, central, and northeastern parts of the quadrangle. It overrode the uplands of Elephant Back Mountain and Stonetop Mountain 

in the central part. In the northern part, the surface of the ice was 

lower, for the highest Pinedale deposits, represented by end moraines 

and embankments of thick till, lie at an altitude of 8,950 feet (2,728 m) 

on the eastern slope of the upland northwest of Fern Lake and at an 

altitude of 8,760 feet (2,670 m) on the western slope. The upland itself 

shows no evidence of having been crossed by the main icecap but may 

have supported a local cap or snow dome. 

As the icecap was forming in the basin of Yellowstone Lake, a large 

glacier was also developing in the drainage of the Lamar and Yellowstone Rivers in the region north of this quadrangle (Howard, 1937; 

Pierce, 1974). That this northern ice spread laterally southwest to the 

canyon was first recognized by Holmes (1883), who discovered the 

now-famous large granite "glacial boulder" on the rim of the canyon 

near Inspiration Point. He concluded that it had been transported by a 

glacier from a source 20 miles (32 km) to the north. Later, Howard 

( 1937, p. 89) showed, from the distribution of granite erratics, that the 

northern glacier not only advanced over the area in which the canyon 

lies but also spread westward across Hayden Valley. The present study 

fully supports Howard's conclusion. Erratics from northern sources 

are widespread north and south of the canyon in this quadrangle. 

These include large cobbles and boulders of granite and gneiss derived 

from far to the north, pebbles and small well-rounded cobbles of 
CANYON VILLAGE QUADRANGLE, QUATERNARY HISTORY 21 

granite and quartzite from a conglomerate of probable Pliocene or 

early Pleistocene age on the southeast side of Hedges Peak (Tower 

Junction quadrangle), irregular fragments of an agglutinate phase of 

the tuff of Sulphur Creek from the canyon rim west of Sevenmile Hole, 

and fragments of obsidian from the Dunraven Pass rhyolite flow (Rdp), 

all to the north. South of the canyon, the erratics also include cobbles of 

biotite diorite from the diamicton at Lower Falls (possibly also from 

their original source in an Eocene stock exposed on the south slope of 

Mount Washburn in the Tower Junction quadrangle), and fragments 

of chalcedonic sinter from the area of Artist Point. All of these erratics 

must have been transported by southward-flowing Pinedale ice. That 

they are not reworked from older glacial or lake deposits is indicated by 

the absence of erratics of northern derivation in older deposits in this 

area. 

The erratics of granite, gneiss, and quartzite extend to higher altitudes than the other erratics. Northwest of the canyon, in the Tower 

Junction quadrangle, a 2-foot (0.6-m) boulder of granite was reported 

by Howard (1937, p. 87) near the Dunraven Pass road at an altitude of 

8,490 feet (2,588 m). I have found boulders of granite and gneiss at 

altitudes of as much as 8,760 feet (2,670 m) on the two ridges southeast 

and south of Hedges Peak (Tower Junction quadrangle). On both 

ridges and in the intervening stream gullies the erratics are moderately 

abundant. Few were found on ridge slopes, owing to a mantle of 

colluvium. To the west, erratics become increasingly sparse. The highest were found at altitudes which decrease westward from 8,760 feet 

(2,670 m) to 8,520 feet (2,597 m) northeast of Cascade Lake in the 

Mammoth quadrangle. The erratics consist of cobbles and boulders 

6-14 inches (15-35 em) in diameter and of smaller stones. Most are of 

gray hard unweathered Precambrian crystalline rock. However, some 

of the small crystalline stones are stained yellow or brown and some are 

rotted. Some small quartzite stones are also stained and have weathered rinds. These small stones are believed to be derived from a 

conglomerate of probable Pliocene or early Pleistocene age that is 

exposed locally southeast of Hedges Peak. Southeast of the canyon, the 

highest granite boulders lie at an altitude of only 8,080 feet (2,460 m), 2 

miles (3.2 km) northeast of Point Sublime. The 420-foot (125-m) difference in maximum altitude of erratics northwest and southeast of the 

canyon suggests that the crystalline-bearing glacier from the north 

abutted ice bearing erratics of basalt and andesite from sources to -the 

southeast. This suggestion is supported by evidence in Hayden Valley. 

The zone of granite-bearing drift in the area of the canyon is about 4 

miles (6.5 km) wide. South of the canyon, this drift is present on the 

upland immediately east of the Yellowstone River as far south as the 

confluence of Sour Creek. Immediately west of the Yellowstone River, 

it extends as far south as the north slope of Crater Hills. Farther west, 
22 YELLOWSTONE NATIONAL PARK, WYOMING 

granite en_·atics occur sparingly in a band of drift about 8 miles ( 13 km) 

wide that extends across the Norris Junction quadrangle (Richmond 

and Waldrop, 1975) between the south flank of the Washburn Range 

in the Mammoth quadrangle, adjacent to the north, and the central 

axis of Hayden Valley at elevations of as much as 8,520 feet (2,600 m). 

Howard ( 1937, p. 87) reported an erratic of granite on Mary Mountain 

(Norris Junction quadrangle) at an altitude of about 8,500 feet (2,590 

m). The glacier-bearing crystalline erratics were therefore at least 720 

feet (220 m) thick in Hayden Valley and must have been in contact 

along the axis of the valley with ice from the southeast. Such a confluence of the two ice masses was suggested by Howard (193 7, p. 92) for 

other reasons. 

Though the existence of Pinedale Till in Hayden Valley has been 

debated, there is no doubt that Pinedale glaciers traversed the lake 

sediments (bl) of late Bull Lake age in that area. Hague, Weed, and 

Iddings (1896) and De Martonne (1915) failed to recognize the lake 

sediments and considered all of the deposits to be moraine. Howard 

(1937, p. 93) found that varved and laminated lake sediments underlay 

the broad high divides and denied the existence of moraine. Both 

conclusions are, in part, correct. As stated, lake silt of late Bull Lake 

age, in which I found no erratics, underlies the divides. However, there 

is clear evidence that these deposits were deeply eroded during the 

Bull Lake-Pinedale interglaciation by ravines graded to the trench of 

the Yellowstone River, and that Pinedale glaciers from both northeast 

and southeast subsequently left their deposits on this dissected terrain. 

Pinedale Till as much as 15 feet (4.6 m) thick mantles the walls of the 

trench and the southeast slopes of divides in the southeastern part of 

Hayden Valley. Thin till locally mantles the divides and northwest 

slopes. In the western part of Hayden Valley (Norris Junction quadrangle; MI-650, Richmond and Waldrop, 1975), a veneer of glacial 

stones, including erratics, mantles the dissected lake silt. Along the 

highway south from Upper Falls (Norris Junction quadrangle), crumpling, folding, and mixing of the upper few feet of the silt beneath 

Pinedale Till indicate overriding by Pinedale ice. 

STAGNATION OF THE PINEDALE ICECAP 

After the Pinedale icecaps had begun to recede, several secondary 

readvances of the ice took place in middle Pinedale time. The terminal 

moraines of the younger of these advances lie in the Norris Junction 

quadrangle (MI-650, Richmond and Waldrop, 1975) west of this 

quadrangle. 

In the Canyon Village quadrangle, the upper limit of one middle 

Pinedale readvance (PM) is recorded by discontinuous lateral 

moraines, morainal embankments, and ice-marginal drainage outlets 
CANYON VILLAGE QUADRANGLE, QUATERNARY HISTORY 23 

around the upland extending northwest from Fern Lake to the Grand 

Canyon of the Yellowstone. These features lie about 400 feet (120m) 

below the maximum upper limit of Pinedale ice northwest of Fern 

Lake and slope northwest to the canyon where they are about 700 feet 

(215 m) below the maximum upper limit 5 miles (8 km) east of the 

canyon. 

Following the read vance, both the southern and northern ice masses 

wasted rapidly. As uplands appeared from beneath the ice, ice-contact 

gravelly sand (pkgs) was deposited around, or upvalley from, the ice. 

The highest deposits are northwest of Stonetop Mountain at an altitude of 8,400 feet (2,560 m), 670 feet (204 m) above present Yellowstone Lake. They extend down the valleys northwest of Stonetop 

Mountain and the melt waters which deposited them probably drained 

across ice in Hayden Valley and westward into the Norris Junction 

quadrangle. A small deposit, also at an altitude of 8,400 feet (2,560 m), 

on the south side of Sulphur Hills owes its location to melting of the ice 

over local hot springs. Other deposits related to local hydrothermal 

activity are the ice-dammed lake silt in the area of Hot Springs Basin 

Group, also at 8,400 feet (2,560 m) altitude, and probably some of the 

ice-contact gravelly sand rna pped as Bull Lake in age (bkgs) at Josephs 

Coat Springs. A Pinedale hydrothermal explosion deposit (phe) and 

crater near Josephs Coat Springs suggest that area may have been the 

locus of a small ice-marginal lake in Pinedale time. Muffler, White, and 

Truesdell (1971) proposed that some hydrothermal explosions may be 

caused by the sudden release of water from a lake overlying an area of 

hot springs. Another hydrothermal explosion deposit (phe) forms a 

ridge around a crater at Fern Lake, 5 miles (8 km) to the southeast. 

After further downwasting of the icecap, ice-contact gravelly sand 

(pkgs) was deposited on and adjacent to the ice in the valley of Astringent Creek, on the slopes around Yellowstone Lake, and in the area of 

LeHardys Rapids. In the valley of Astringent Creek the deposits lie 

between altitudes of 8,500 feet (2,590 m) and 8,040 feet (2,450 m), or 

between 770 feet (235 m) and 310 feet (94 m) above present Yellowstone Lake. They contain small pebbles of pumice derived from outcrops of the tuff of Sulfur Creek at the margin of the Canyon rhyolite 

flow (Rc) to the north, indicating that the local drainage was to the 

south. The deposits show unusually well-developed ice-contact slopes. 

The basins of White Lake and Fern Lake are huge kettles formed when 

buried ice masses melted. An esker (peg) at the narrows of White Lake 

marks the former position of a subglacial stream. On the east side of 

Yellowstone Lake, ice-contact sandy gravel (pkgs) mantles the slopes 

south of Lake Butte between altitudes of 8,240 feet (2,510 m) and 

7,840 feet (2,390 m), or between 510 feet (155m) and 110 feet (33m) 

above present Yellowstone Lake, and extends upslope to higher altitudes in the Pelican Cone quadrangle (MI-638, Richmond and Wal-
24 YELLOWSTONE NATIONAL PARK, WYOMING 

drop, 1972), adjacent to the east. On the west side of Yellowstone Lake, 

ice-contact gravelly sand (pkgs) extends from an altitude of 8,200 feet 

(2,500 m), or 470 feet (143m) above present Yellowstone Lake, down 

to 7,840 feet (2,390 m), or 110 feet (33m) above the lake. The deposits 

form a series of broad discontinuous kame terraces. In the valley of the 

Yellowstone River near present LeHardy's Rapids, thick ice-contact 

deposits of gravelly sand (pkgs) extend from river level upslope over 

ridges of tuff of the Yellowstone Group (through which the river had 

cut its course during the Bull Lake-Pinedale interglaciation) and form 

a sequence of terraces at altitudes of 8,040, 7,880 and 7,840 feet (2,450, 

2,402, and 2,390 m) or 310, 150, and 110 feet (94, 46, and 33m) above 

present Yellowstone Lake. The highest of these terraces, which is at the 

same altitude as the lowest ice-contact deposits around Yellowstone 

Lake, is a kame terrace formed when ice lay both in Hayden Valley to 

the north and in the area of Yellowstone Lake to the south. The lower 

two are erosion terraces cut in the deposits of the highest terrace. In 

the southern part of Hayden Valley, at the west edge of the quadrangle, ice-contact gravel underlies an irregular surface that slopes northward from an altitude of 8,000 feet (2,438 m) to 7,800 feet (2,377 m). 

As downwasting continued in the basin of present Yellowstone Lake, 

silt (pkl) was deposited in small lakes marginal to the ice. One such lake, 

ancestral to Yellowstone Lake, first developed at an altitude of 8,360 

feet (2,548 m) in an area of thermal activity on the west side of the basin 

of Astringent Creek. Further down wasting of the ice extended the lake 

eastward and southward toward Pelican Valley at gradually decreasing 

surface levels. At about the same time, another ice-marginal lake developed at an altitude of 8,240 feet (2 ,511 m) in the headwaters of 

Pelican Valley in the Pelican Cone quadrangle (MI-638, Richmond and 

Waldrop, 1972) adjacent to the east. In like manner, this lake opened 

southward and westward down Pelican Valley into this quadrangle at 

gradually decreasing surface levels until it merged with the lake in the 

valley of Astringent Creek at an altitude of 8040 feet (2,450 m), or 310 

feet (94 m) above present Yellowstone Lake. At this altitude the lake 

was probably retained by ice in the basin of Yellowstone Lake at about 

the position of the present north-west trending ridge north of Mary 

Bay. Its outlet was through a channel at an altitude of 8,040 feet (2,450 

m) north of Ebro Springs. From the channel it drained along the edge 

of the ice (at about the position of the present unnamed stream south 

of Thistle Creek) into melt waters flowing on a gradient of about 40 

feet/mile (7 .6 m/km) from the ice front east of Ochre Springs across the 

kame terrace gravel (pkgs) at an altitude of 8,040 feet (2,450 m) 

southwest of LeHardys Rapid onto and around ice in Hayden Valley. 

From this ice it probably drained westward through a large channel, 

recognized by Howard (1937, p. 99), which extends westward from 

moraines in the headwaters of Cascade Creek (Mammoth quadrangle; 
CANYON VILLAGE QUADRANGLE, QUATERNARY HISTORY 25 

MI-641, Pierce, 1973) at an altitude of about 8,040 feet (2,450 m) 

through Cascade, Grebe, and Wolf Lakes (Norris Junction and Mammoth quadrangles) into the drainage of the Gibbon River. The channel 

marks the last westward flow of water from the drainage of the Yellowstone River. 

Subsequently, the ancestral lake was lowered 200 feet (60 m) to an 

elevation of 7,880 feet (2,402 m) or 150 feet (46 m) above present 

Yellowstone Lake. The lowering was probably caused by wasting of the 

ice from the hills south of the unnamed stream south of Thistle Creek 

and was probably sudden and extraordinarily rapid. It was not caused 

by movement on the east-trending fault across LeHardys Rapids because Pinedale Till (pt) and overlying ice-contact gravelly sand (pkgs) 

extend unbroken across the fault (stratigraphic sections 38 and 39). 

Lowering of the lake reduced its confining pressure on the hy~ 

drothermal area around Mary Bay and triggered a hydrothermal explosion or group of closely spaced explosions in that area. According to 

Muffler, White, and Truesdell (1971), hydrothermal explosions are 

commonly caused by the rapid fall of a lake. The explosion deposit 

(phe), the largest known in the park, forms a broad hemi-elliptical 

ridge around the north and east sides of Mary Bay. The ridge is about 

200 feet (60 m) high and Y2-l Y2 miles (0.8-2.4 km) wide. The inside 

long dimension of its arc is about 3 miles ( 4.8 km). An elliptical depression shown in Mary Bay on an unpublished reconnaissance map of the 

floor of Yellowstone Lake by the U.S. Fish and Wildlife Service may be 

a remnant explosion crater. It is nearly 1 mile ( 1.6 km) long and has a 

maximum depth of more than 160 feet (49 m). 

The explosion deposit (phe) is well exposed along the service road to 

Turbid Lake. In places it is 140 feet (43 m) thick (stratigraphic section 

71). In the bluff east of Mary Bay it rests on lake sand (pksl) (stratigraphic sections 69, 70) which overlies Pinedale Till (pt) (stratigraphic 

section 71). In the bluff southeast of Squaw Lake (stratigraphic sections 

73, 75, 76) it disconformably overlies varved silt (pl), is locally contorted, and is overlain by fine lake sand (psi) or varved silt (pl). At 

stratigraphic section 76, the outer edge of the hydrothermal explosion 

deposit (phe) intrudes a dark, richly organic lake deposit, carbon-14 

dated as 13,650±600 years old (W-2894) (Meyer Rubin, written commun., 1973), which lies in finely laminated lake sand immediately 

above varved silt (pl). 

In Pelican Valley, the explosion debris (phi) is silty and weakly 

bedded, as if deposited in or reworked by the lake. The deposit (phi) 

rests disconformably on lake-bottom silts (stratigraphic sections 49, 50, 

51, 52, 53). Beyond the limits of the debris (phi), a distinct though 

slight disconformity separates silts deposited before and after the explosion (stratigraphic section 45). The water in Pelican Valley, displaced violently by the explosion and construction of the ridge, flooded 
26 YELLOWSTONE NATIONAL PARK, WYOMING 

across the hills south of the unnamed stream south of Thistle Creek, 

where it produced a local scabland topography. Backwash of the waters 

flooded through four distinct channels across the ridge of explosion 

debris into the explosion crater. The lake in Pelican Valley settled at an 

altitude of 7,880 feet (2,402 m) for a short time, draining through the 

area of LeHardys Rapids across the kame terrace deposit (pkgs) at that 

altitude. It was then lowered by erosion of its outlet through the ridge 

west of Vermilion Springs to an altitude of 7,840 feet (2,390 m), 110 

feet (33 m) above present Yellowstone Lake, and merged with water 

ponded in front of and around the margin of the ice in the basin of 

Yellowstone Lake. The upper limit of the lake at this altitude is marked 

by two terraces; one, underlain by lake-reworked explosion debris 

(phi), is on the southwestern slope of the ridge of hydrothermal explosion debris, and the other, underlain by beach gravel (pklb), is on the 

slopes northwest of Yellowstone Lake. In the southern part of the 

quadrangle and farther south around Yellowstone Lake, a 110-foot 

(33-m) terrace is also well developed but has ice-contact features, indicating that only a narrow irregular strip of water, ponded between 

stagnant ice in the basin and the adjacent hill slopes, lay in these areas. 

The northern limit of the ice was probably along the abrupt lobate 

slope shown by contours on the floor of Yellowstone Lake east of 

Stevenson Island (from U.S. Geological Survey topographic map of 

Yellowstone National Park, 1961). Stevenson Island is underlain 

largely by ice-dammed lake sand (pksl). The outlet of the lake was at 

the level of the erosional terrace cut in ice-contact sandy gravel (pkgs) 

at an altitude of 7,840 feet (2,390 m), 110 feet (33 m) above present 

Yellowstone Lake, at LeHardys Rapids. 

South of this quadrangle, other strand lines and terraces, 90 and 

80-75 feet (27 and 24-23 m) above present Yellowstone Lake, are 

believed to have been controlled by pauses in the erosion of the outlet, 

which, in turn, were probably controlled by stagnation of the ice in 

Hayden Valley. Their discontinuous nature and, for the most part, 

poor development suggest that they represent ony minor and shortlived stands during a time of falling water level. These strand lines 

were not noted in this quadrangle. Lake sediments younger than the 

hydrothermal explosion deposit at Mary Bay contain evidence for the 

time when Yellowstone Lake became fully open. Thinly laminated 

wavy beds of fine lake sand, exposed in the bluffs of the lake southeast 

of Squaw Lake, immediately overlie the explosion deposit (stratigraphic sections 73, 74, 75, 76). At stratigraphic section 75, a thin layer 

of volcanic ash, identified by R. E. Wilcox (written commun., 1972) as 

probably the Glacier Peak ash but possibly the Mount St. Helens J ash, 

was found in the sand, 2 feet (0.6 m) above the explosion deposit. The 

Glacier Peak ash is 12,000 or 12,600 years old and the Mount St. 

Helens J ash is probably about the same age. Both are from sources in 
CANYON VILLAGE QUADRANGLE, QUATERNARY HISTORY 27 

the Cascade Range in Washington. Either would be about 1,000 years 

younger than the explosion deposit (carbon-14 age, 13,600±600 

years). Charcoal found at a point 4.4 feet (1.34 m) above the ash 

yielded a carbon-14 age of 10,720±350 years (W-2738, Meyer Rubin, 

written commun., 1972). An ash bed, identified by Wilcox as the same 

as that at stratigraphic section 75, occurs-in laminated silt in the bluff of 

Yellowstone Lake south of Gull Point (stratigraphic section 92), and, in 

the Frank Island quadrangle (Richmond, 1974), at the entrance to Flat 

Mountain Arm and along Grouse Creek. At the latter locality, the ash is 

4 feet ( 1.2 m) above the base of the laminated silt which, in turn, 

overlies varved silt. Organic matter 4 feet ( 1.2 m) above the ash yielded 

a carbon-14 age of 9,060±300 years (W-2041; Sullivan and others, 

1 970). In the Canyon Village quadrangle, just north of the ridge of 

hydrothermal explosion debris (phe) in Pelican Valley at stratigraphic 

section 45, a pair of thin ash beds, 6 inches ( 15 em) apart, occur in the 

thinly laminated foreset-bedded silt of a delta which disconformably 

overlies varved silt. These ash laminae have not been identified but 

may be the Glacier Peak or Mount St. Helens J ash bed. 

The broad distribution of the ash around northern, western, and 

southwestern parts of Yellowstone Lake and its position in nonvarved 

sediments overlying varved sediments indicate that by 12,000 or 12,600 

years ago the lake was free of ice. The relatively small amount of 

sedimentation, 2-4 feet (0.6-1.2 m), during the 1,200 to 2,000 years 

following deposition of the ash contrasts markedly with the underlying 

thickly varved beds and further suggests that the lake was fully ice free 

at the time the ash fell. 

In Hayden Valley the ice from both northern and southern sources 

appears to have remained intact for some time and then to have 

downwasted very rapidly. Discontinuous ice-contact deposits of 

gravelly sand (pkgs) as high as 8,000 feet (2,438 m) altitude east and 

west of the southern part of Hayden Valley and the absence of lake 

deposits of Pinedale age at this level suggest that melt-water streams 

flowed north both on and marginal to ice in Hayden Valley and in the 

basin of Sour Creek. They probably drained through an outlet channel 

at an altitude of about 7,980 feet (2,432 m) 2 miles (3.2 km) northeast 

of Silver Cord Cascade and onto ice in the Grand Canyon of the 

Yellowstone. The surface of the ice in Hayden Valley was probably 

eroded by floodwaters resulting from the hydrothermal explosion and 

concurrent rapid fall of the lake in Pelican Valley to a level 110 feet 

(33 m) above present Yellowstone Lake. In the southern part of Hayden Valley, lake sediments (pkl) at and below an altitude of 7,840 feet 

(2,390 m) show that a lake 110 feet (33 m) above present Yellowstone 

Lake also occupied this area. These sediments are the "plains sediments" of Howard (1931, p. 94) in Hayden Valley. The level of this 

lake probably controlled that of the lake at the same altitude in the 
28 YELLOWSTONE NATIONAL PARK, WYOMING 

basin of Yellowstone Lake. The two may have been essentially continuous across the erosional terrace cut on ice-contact sandy gravel (pkgs) at 

an altitude of 7,840 feet (2,390 m) in the area of LeHardys Rapids. The 

lake in Hayden Valley was dammed by the front of ice from the north, 

which lay along the slopes north of Crater Hills and to the northeast, 

east of the Yellowstone River. For a time, it probably drained north 

across ice in the lower valley of Sour Creek and through successively 

lower well-marked outwash channels cut in rock at altitudes of 7,840 to 

7,800 feet (2,390 to 2,377 m) between Ribbon Lake and Clear Lake, 

onto ice or into a lake in the Grand Canyon of the Yellowstone. 

A thick basal sand and an overlying succession of five conformable 

sequences of varved silt were deposited in the lake. These sediments 

are exposed in the bluff of Trout Creek at stratigraphic section 35. 

Each varved sequence grades from mega varves at its base to thin varves 

at its top, and each is separated from its successor by a very thin layer of 

fine sand. No erosion seems to have taken place between sequences. 

The succession probably was the result of minor changes iH lake regimen, but its precise meaning is obscure. 

Subsequently, the ice in the basin of Sour Creek and in northern 

Hayden Valley deteriorated, and the drainage shifted to a course over 

ice in the sheltered canyon of the Yellowstone River north of Hayden 

Valley. At this time the lake level was lowered gradually about 100 feet 

(30m) to an altitude of 7, 700 feet (2,34 7 m). As the lake was lowered, a 

thin sheet of gravel (pgs), possibly a recessional beach deposit, was 

spread out over the lake deposits (pl). The level of the lake at 7, 700 feet 

(2,34 7 m) is marked by the surface of a large delta of gravelly sand 

(pdgs) well exposed at stratigraphic section 21 in the basin of Sour 

Creek. 

Final deterioration of the ice in the canyon of the Yellowstone River 

north of Hayden Valley and drainage of this lake was probably catastrophic. Ragged scablike pillars of rock in the Yellowstone River below 

Chittenden Bridge (Norris Junction quadrangle) suggest flood scour of 

the river channel. A flood also took place along the trench of the 

Yellowstone River at the head of the lake at this time. A deposit of this 

flood (pfd) at least 60 feet ( 18 m) thick is exposed in a highway cut at 

stratigraphic section 34. The deposit appears to be a flood bar, the top 

of which is at an altitude of 7, 760 feet (2,365 m). The deposit is banked 

in near-vertical contact against Pinedale Till and underlying lake deposits of late Bull Lake and intra-Bull Lake age. To the west, in the 

bluff north of Trout Creek, thin layers of older flood deposits, possibly 

related to the flood immediately preceding the 110-foot (33-m) lake 

level, are interbedded in the basal sandy deposits of that lake. To the 

east, a younger alluvial terrace deposit (pgs) lies in steep contact against 

the flood deposit. The flood was probably associated with one of the 
CANYON VILLAGE QUADRANGLE, QUA TERNARY HISTORY 29 

drops in the level of Yellowstone Lake after its stand at the 110-foot 

(33-m) level, but no specific relation can be established. 

In the Grand Canyon of the Yellowstone, wasting of the ice was 

probably rapid owing to the local extensive hydrothermal activity. A 

small deposit of lake silt, first noted by Howard (1937, p. 106) on the 

west wall of the canyon below Lower Falls, has steeply dipping laminae 

and appears to have formed in water ponded by ice in the canyon. 

Talus deposits on the east wall of the canyon below Lower Falls contain 

abundant well-rounded cobble gravel, chiefly of rhyolite but including 

unaltered obsidian, basalt, andesite, diorite, granite, gneiss, and red 

and white quartzite. This gravel is traceable upslope to a bed of gravel, 

mixed with, and mostly covered by, talus, that is perched on the canyon 

wall about 200 feet (60 m) above the river. The gravel was probably 

deposited by a stream marginal to ice in the canyon. 

Lakes probably existed in the hydrothermal areas below Lower Falls 

and in Sevenmile Hole at least by the time of the flood caused by the 

giant hydrothermal explosion and catastrophic lowering of the lake in 

the basin of Yellowstone Lake to its 110-foot (33-m) level about 13,650 

years ago. Erosion by this and other floods probably deepened the 

canyon and undercut its walls. Howard (1937, p. 106) described a 

sandstone block, about 50 feet (15 m) above river level on the east side 

of the canyon along the trail downstream from the observation platform below Lower Falls, which he believed had fallen from the canyon 

rim. The block is 30-40 feet (9-12 m) long, and the bedding of the 

sandstone strikes N. 25° W. and dips 25° S. Its lithologic characteristics 

are identical to those of silica-cemented sand (uf, unit 1) on the rim of 

the canyon upslope. Such blocks could easily have fallen during or 

shortly after undercutting of the canyon wall by a flood. 

Just north of this quadrangle, near the south edge of the Tower 

Junction quadrangle, varved lake silt at an altitude of 7,400 feet (2,255 

m) in a reentrant on the west slope of the canyon records the locus of 

an ice-marginal pond 800 feet (244 m) above the river. In this quadrangle, varved silt, overlying Pinedale gravel and till (stratigraphic 

section 1) at an altitude slightly less than 6,800 feet (2,073 m), formed 

in a lake dammed in the canyon at that altitude by an ice margin 

downstream north of Tower Fall. The lake was first recognized and its 

deposits described by Howard (1937, p. 127-134), who named it Retreat Lake. It is further discussed by Pierce (MI-647, 1974). 

POSTGLACIAL HISTORY OF THE 

GRAND CANYON OF THE YELLOWSTONE 

Since drainage of Retreat Lake, 40-80 feet (12-24 m) of its sediments 

and older deposits have been stripped from the canyon floor, and the 
30 YELLOWSTONE NATIONAL PARK, WYOMING 

canyon walls have been eroded by mass-wasting processes associated 

with the development of landslides, mudflows, and talus. A mudflow 

deposit (pmf) containing wood, carbon-14 dated as 10,900±350 years 

old (W-2736) (Meyer Rubin, written commun., 1973), rests on gravel 

(pg) and till (pt) of Pinedale age about 15 feet (4.6 m) above river level 

at stratigraphic section 2. At the same locality, laminated silt of a 

landslide-dammed lake contains logs, one of which yielded a carbon-14 

age of 2,430±250 years (W-2735) (Meyer Rubin, written commun., 

1973). The logs were coated with sulfur and completely carbonized by 

local hydrothermal activity. Downstream, in the southern part of the 

adjacent Tower Junction quadrangle, logs from the same bed are 

altered to white splintery silicified wood. At another locality, at river 

level in the southern part of the Tower Junction quadrangle, a log 

from soft lake silt immediately upstream from a large landslide yielded 

a carbon-14 age of 540±250 years (W-2766) (Meyer Rubin, written 

commun., 1973). In June 1971 a landslide developed in hydrothermally altered talus and underlying rock on the east wall of the canyon 

in the Canyon Village quadrangle opposite stratigraphic section 3. The 

slide raised the floor of the river, bringing Pinedale Till and overlying 

deposits to the surface in the channel. The slide dammed the river to a 

height of approximately 40 feet (12m) above its normal level, as shown 

by the presence of flood trash and boulders around the toe of the slide 

and upstream. Damming was probably brief, for the river broke across 

the eastern part of the slide deposit, cutting a new channel and leaving 

a deep pool, informally known as Threemile Hole, upstream from the 

western part of the deposit. 

POSTGLACIAL HISTORY OF YELLOWSTONE LAKE 

Since disappearance of the icecap from the basin of Yellowstone 

Lake about 12,000 or 12,600 years ago, the lake has existed as a body of 

open water at successively lower levels. A prominent terrace and associated well-sorted l~custrine deposits extend almost continuously 

around the lake at a level 60-65 feet (18-20 m) above it. The deposits 

of this terrace differ from those at higher levels in that they are 

characterized by numerous large spits, bars, and lagoonal depressions, 

indicative of strong longshore currents found only in a large body of 

open water. The presence of large deltas at the 60- to 65-foot (18- to 

20-m) level along Pelican Creek, Sedge Creek, and Bridge Creek, as 

well as the width and continuity of the terrace, suggests that the lake 

maintained itself at this level for a fairly long time. No evidence of the 

age of the terrace was found in this quadrangle. However, along 

Grouse Creek in the Frank Island quadrangle (MI-642, Richmond, 

197 4), foreset-bedded sand deposits of a prograding delta at the 60- to 
CANYON VILLAGE QUADRANGLE, QUATERNARY HISTORY 31 

65-foot (18- to 20-m) level overlie lake silts containing organic matter 

that was carbon-14 dated as 9,060±300 years old (W-2041; Meyer 

Rubin, written commun., 1972). The 60- to 65-foot (18- to 20-m) 

terrace is therefore younger than 9,060±300 years. 

The outlet waters of the lake probably flowed across the silicacemented lake sand (pbsl) of Bull Lake-Pinedale interglacial age that 

underlies the area between Pelican Creek and the Yellowstone River 

and served to retain the lake in the same way that compact silt (pbl) of 

the same age retains present Yellowstone Lake at Fishing Bridge. The 

outlet at the time of the 60-foot (18-m) lake level is estimated to have 

been about 1.5 miles (2.4 km) north of Fishing Bridge. It might be 

imagined that the lake extended north to the outlets cut in rock (mentioned above) southeast of the canyon at an altitude of about 7,800 feet 

(2,377 m), approximately 60 feet (18 m) above present Yellowstone 

Lake. However, this seems impossible because those outlets show no 

evidence of long-term use. Furthermore, there is no gravel terrace and 

no lake silt at the 60-foot (18-m) level in the valley of the Yellowstone 

River south and west of LeHardys Rapids. 

Although no glacial deposits of late Pinedale age are present in this 

quadrangle, outwash of late Pinedale age is graded to the 60-foot 

(18-m) terrace at the southeast end of Yellowstone Lake (MI-637, 

Richmond and Pierce, 1972). Late Pinedale time is therefore included 

in the time of formation of the 60-foot (18-m) terrace. 

A hydrothermal explosion deposit (he) forms a ridge around Turbid 

Lake, the site of the crater from which the material was ejected. The 

deposit rests on a layer of subaerial organic matter carbon-14 dated as 

8,000±500 (W~2486; Meyer Rubin, written commun., 1969) and 

8,310±300 years old (W-1944; Marsters and others, 1969). The explosion does not seem to have been related to a falling lake level, because 

the preexisting-terrain was 100-125 feet (30-38 m) above the 65-foot 

(20-m) terrace. 

Lake terraces and associated lake deposits, 50-55, 40-45, and 30-35 

feet (15-17, 12-14, and 9-11 m) above Yellowstone Lake are considered to have formed during the "altithermal" interval. A stream terrace 

entrenched about 8 feet (2.5 m) below the floor of the drained lake in 

Pelican Valley is itself entrenched 15 feet (4.5 m) by the modern flood 

plain. The terrace is probably related to the 40- to 45-foot (12- to 14-m) 

lake terrace, though this cannot be proven. Twigs from a boggy sand 

layer beneath the stream terrace gravel yielded a carbon-14 age of 

5,900±300 years (W-2580) (Meyer Rubin, written commun., 1969). 

Organic matter from a lagoonal deposit of the 40-foot (12-m) terrace in 

the Frank Island quadrangle (MI-642, Richmond, 1974) is older than a 

minimal date of 5,590±250 years (W-2286) (Meyer Rubin, written 

commun., 1969). Lowering of the lake from the 30- to 35-foot (9- to 
32 YELLOWSTONE NATIONAL PARK, WYOMING 

11-m) level to the 25-foot (7.6-m) level touched off a hydrothermal 

explosion, the crater of which is at Squaw Lake (Canyon Village quadrangle). In the bluff of Yellowstone Lake southeast of Squaw Lake, the 

hydrothermal explosion deposit (he) overlies thinly laminated wave 

beds of fine sand (psl) (stratigraphic sections 73, 74, 75, 76) that appear 

to represent off~hore deposits of the lake at the 60-foot (18-m) terrace 

level. To the east, at stratigraphic section 74 where the modern bluff 

has cut inland from the 25-foot (7.6-m) terrace, the explosion deposit is 

overlain by limonite-stained sandy silt and organic-rich clay, carbon-14 

dated as 3,500±250 years old (W-2734) (Meyer Rubin, written commun., 1972). Where the bluff crosses the 25-foot (7.6-m) terrace, the 

terrace is cut on the explosion deposit and its associated beach gravel is 

overlain by younger colluvium and dune sand. 

Terraces 25, 15, and 10 feet (7.6, 4.6, and 3 m) above the lake are 

probably all of post-Altithermal age. Charcoal under colluvium overlying beach gravel of the 10-foot (3-m) terrace has a radiocarbon age of 

620±250 years (W-1999; Meyer Rubin, written commun., 1968). 

OTHER POSTGLACIAL EVENTS 

Very few postglacial solifluction or mass-wasting deposits were recognized in the quadrangle, though such activity probably occurred on 

till-covered slopes, especially where the till overlies lake silts. A block 

landslide on the south slope of the valley of Sour Creek probably 

formed during recession of the ice. A few small slump landslide deposits were mapped, for example, at Turbid Lake. 

Postglacial stream erosion and alluviation have been remarkably 

slight. Postglacier-related deposits are dissected 15-30 feet (4.5-9 m). 

Much of this was probably accomplished during floods or drops in lake 

level. Pelican Creek meanders in thin alluvium (fa) in a broad shallow 

trench only about 8-10 feet (2.5-3 m) deep. Underlying lake silts are 

exposed in the creek in several places. The outlet of Yellowstone Lake 

at Fishing Bridge is on compact lake silt (stratigraphic sections 78, 79). 

In the Grand Canyon of the Yellowstone, the river has eroded through 

as much as 40 feet of soft sediments but has cut only 10-15 feet (3-4.5 

m) into hydrothermally altered rhyolite. Postglacial gullies on hillsides 

are mostly only 15-20 feet (4.5-6 m) deep. Alluvial fans (fa) at the foot 

of slopes are small. Changes in the shoreline of Yellowstone Lake may 

have been considerable. Large spits and bars in the lake denote extensive modern longshore transport. Storm waves have been observed to 

strip away as much as 4 feet (1.2 m) of the bluff southeast of Squaw 

Lake in less than an hour. Such catastrophic erosion, though perhaps 

rare, has probably effected significant changes in the shoreline over the 

years. 
CANYON VILLAGE QUADRANGLE, QUATERNARY HISTORY 33 

HYDROTHERMAL ACTIVITY 

The hydrothermal activity in the park is being studied by D. E. White 

and others. Acid alteration of the rhyolite in the Grand Canyon of the 

Yellowstone is probably old, although many small thermal springs and 

gas vents lie between Lower Falls and Inspiration Point, and north of 

the great bend of the Yellowstone River near the north edge of the 

quadrangle. Other areas where acid alteration of bedrock is widely 

associated with hot springs or fumaroles include Sulphur l·Iills, the 

area west of Astringent Creek, and several areas north of Sour Creek 

on the southern slope of the Canyon rhyolite flow (Rc). The area of 

alteration, including Sulphur Springs, west of Crater Hills, is in icecontact gravel (bkgs) and ice-dammed lake silt (bl) oflate Bull Lake age. 

It includes at least one geyser. Other hot springs occur in ice-contact 

gravels at and near Josephs Coat Springs (including Whistler Geyser), 

along the Wapiti Lake Trail at Moss Creek, at Ochre Springs, in the 

Sulphur Hills, and at Steamboat Point. Hot springs and mud pots in 

lake silts are characteristic of the Mud Volcano area, Ebro Springs, 

Vermilion Springs, the Ponuntpa Springs Group, the Hot Spring Basin 

Group, and along the valleys of Pelican Creek, Astringent Creek, Sour 

Creek, and Cottongrass Creek. Hot springs occur in beach deposits 

around Mary Bay and westward to Pelican Creek, and beach deposits 

of older high stands of the lake have been cemented by silica-bearing 

waters in many places. Hot springs are also common in the hydrothermal explosion deposits around Mary Bay, Turbid Lake, Squaw Lake, 

Fern Lake, and near Josephs Coat Springs. 

QUATERNARY FAULTING 

Most of the quadrangle lies within a caldera whose collapse followed 

eruption of a widespread tuff of the Yellowstone Group about 600,000 

years ago (Christiansen and Blank, 1972). The wall of the caldera 

trends northeast across the quadrangle east of Broad Creek. The faults 

shown on the map (I-652) are chiefly from R. L. Christiansen and H. 

R. Blank Jr. (1975). All are normal faults. Two sets trend northwest 

and northeast respectively across the elongate domelike hill in the 

central part of the quadrangle. The northwest-trending set was first 

recognized by Love (1961). Christiansen and Blank (1972) have shown 

that the domelike hill is the resurgent dome of the caldera and that 

both sets of faults are related to its uplift, shortly after 600,000 years 

ago. North- and northwest-trending faults in the northeast corner of 

the quadrangle record postcaldera movements along the caldera wall. 

Faults trending north-northwest in the area of the Grand Canyon of 

the Yellowstone cut the Canyon rhyolite flow (Rc), about 590,000 years 
34 YELLOWSTONE NATIONAL PARK, WYOMING 

old. The northeast-trending fault in that area appears to displace the 

sediments of Inspiration Point (ip). The group of faults trending 

northeast across Elephant Back Mountain transects the Elephant Back 

rhyolite flow (Re) and the underlying West Thumb rhyolite flow (Rh) 

(K-Ar age about 144,000 years). They are, in turn, displaced by later 

movement on the east-trending fault, downthrown to the north, that 

crosses the Yellowstone River at LeHardys Rapids. None of the faults 

in the quadrangle cut Pinedale or younger deposits. 

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Alden, W. C., 1928, Glaciation of Yellowstone National Park and its environs: Ranger 

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Wyoming: Geol. Soc. America Bull., v. 72, no. 3, p. 387-426. 

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18 p. 

___ 1975, Geologic map of the Canyon Village quadrangle, Yellowstone National 

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Pierce, K. L., 1973, Surficial geologic map of the Mammoth quadrangle and part of the 

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Geol. Survey Misc. Geol. Inv. Map I-641 [1974]. 

___ 1974, Surficial geologic map of the Tower Junction quadrangle and part of the 

Mount Wallace quadrangle, Yellowstone National Park, Wyoming and Montana: 

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___ l973a, Surficial geologic map of the West Thumb quadrangle, Yellowstone National Park, Wyoming: U.S. Geol. Survey Misc. Geol. Inv. Map I-643. 
REFERENCES 35 

___ 1973b, Surficial geologic map of the Huckleberry Mountain quadrangle, Yellowstone National Park and adjoining area, Wyoming: U.S. Geol. Survey Misc. Geol. 

Inv. Map I-639. 

___ 1973c, Surficial geologic map of the Grassy Lake Reservoir quadrangle, Yellowstone National Park and adjoining area, Wyoming: U.S. Geol. Survey Misc. Geol. 

Inv. Map I-644. 

___ 1973d, Surficial geologic map of the Warm River Butte quadrangle, Yellowstone 

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___ 1974, Surficial geologic map of the Frank Island quadrangle, Yellowstone National Park, Wyoming: U.S. Geol. Survey Misc. Geol. Inv. Map I-642. 

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press.) 

Richmond, G. M., and Pierce, K. L., 1971, Surficial geologic map of the Two Ocean Pass 

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Survey Misc. Geol. Inv. Map I-635. 

___ 1972, Surficial geologic map of the Eagle Peak quadrangle, Yellowstone National 

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Richmond, G. M., and Waldrop, H. A., 1972, Surficial geologic map of the Pelican Cone 

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Survey Misc. Geol. Inv. Map I-638. 

___ 1975, Surficial geologic map of the Norris Junction quadrangle, Yellowstone 

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t. U.S. GOVERNMENT PRitm~G OFFICE 1976-777-034/10