JEFFERSON COUNT¥ ENVIRONMENTAL GEOLOGY STUDY
Geologist (125 days@ $125/day) • $ 15,600 *
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Maps: (1) Geology - 4 or 5 color (1 inch= 3 miles) (2) Mineral deposits (combine with geology?) (3) Urban - 7~' - 1:24,000 (black and white)
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Map supplies and equipment --500 TOTAL ESTIMATED COST $13,500 Quaternary glaciation and volcanism, Metolius River area, Oregon WILLIAM E. SCOTT'· Department of Geological Sciences, University of Washington, Seattle, Washington 98195 ABSTRACT INTRODUCTION ington, Cali fornia, and the Rocky Mountain states, few detailed studies of Evidence of three major Quaternary During Quaternary time, the Cascade glaciation in the Oregon Cascades have glaciations is recognized in the Metolius Range of Oregon was repeatedly subjected been published. River area on the east flank of the High to both valley and ice-cap glaciation. The The present study involved the geologic Cascades. T he latest glaciation (Cabot effects of glacial processes in modifying the mapping of surficial deposits along the crest Creek glaciation) is multiple, with evidence original volcanic topography are well dis and eastern flank of the High Cascade of a late readvance (Canyon Creek ad played by deep U-shaped va ll eys, numerous Range in north-central Oregon near three vance) well displayed in cirques. Post cirques, well -developed end moraines, and large Quaternary stratovolcanoes, Mount Altichermal glacial activity is restricted to a deeply eroded stratovolcanoes. However, Jefferson, Three-Fingered Jack, and Mount twofold lace Neoglacial advance on Mount compared with well-studied areas in Wash- Washington (F ig. 1 ). This report describes Jefferson and Three-Fingered Jack. Scone weathering characteristics and soi l devel opment are used to differentiate and corre late the drifts throughout the area. The de gree of soil development on the drifts suggests that there was a longer period of time between the oldest and intermediate glaciations than between the intermediate and youngest glaciations. Volcanic activity may have been re stricted to times of little ice cover, since no evidence of intraglacial volcanism was ob served. Tephra and lava flows were erupted during two Pleistocene interglaciations and during Holocene time at scattered loca tions. The High Cascade platform and probably the scratovolcanoes were largely cons!ructed prior to the earliest recognized glaciation (Ab bott Butte glaciation). In formation on extent of ice cover during the Cabot Creek glaciation and the Neogla cial advance is sufficiently detailed to re construct past glacier margins and estimate former eq uilibrium-line altitudes (ELA). An accumulation-area ratio of 0.6 ± 0.1 was employed to calculate past ELAs. During the Cabot Creek glaciation, ELAs ranged from about 950 m lower than present at the maximum to 700 to 750 m lower than present for the Canyon Creek advance. Neoglacial ELAs on Mount Jefferson glaciers were lower than present by 200 to 250 m. ELA gradients across the Western Cascades during the Cabot Creek glaciation averaged about 5 m/km, increased to 14 m/km across the High Cascades, and were greater than 38 m/km farther east. This re 0 10 20 30 flects a pattern of precipitation similar to km that of the present. • Present address: U.S. Geological Survey, Federal Center, Denver, Colorado 80225. Figure 1. Location of study area. Geological Sociery of America Bulletin, v. 88, p. 11 3-124, 12 figs., January 1977, Doc. no. 70113. 113 114 W. E. SCOTT the stratigraphy of Quaternary glacial and TABLE 1. CRITERIA USED TO DIFFERENTIATE AND CORRELATE DRIFTS volcanic deposits, the extent of former glaciers, and estimated equilibrium-line al Criterion Application References titudes (ELA) of present and former glaciers. Discordance in Well displayed in some valleys with moraines Sharp and Birman (1963) moraine t'rends of both Cabot Creek and Jack Creek age Previous Work Morainal Made subjective judgment of crestal sharp White (1962), Rampton (1971) morphology ness. Proximal and distal moraine slope From their early reconnaissance studies, angles measured by inclinometer Dutton (1889, p. 161) and Russell (1905, p. Weathering characteristics of stones 30) realized that the entire summit platform Surface- Counted number of boulders in 3 m X 30 m Blackwelder (1931), Sharp of the High Cascades had been covered boulder area on moraine crests. Of limited use due (1969) with an ice cap and that outlet glaciers had frequency to variable tephra cover descended the eastern and western slopes Stone-weather- Collected 40 to 186 cobbles and pebbles from Blackwelder ( 1931), Birman and constructed conspicuous end moraines. ing ratios surface to 30-cm depth at sites on moraine (1964), Sharp (1969), Carver Multiple Pleistocene glaciation was first crests and high points on ground moraine. (1972) suggested by Hodge (1925, p. 38-40). Used ratio of unweathered:partly weath ered (rinds, pitting, interior staining, but From studies in the valley of the North San cores still fresh) :totally weathered (no tiam River west of Mount Jefferson, Thayer fresh cores, easily pulverized) (1939) presented firm evidence for a Crandell and Miller (1974 ), threefold glacial sequence that he correlated Thickness of Used pebbles and cobbles from surface to weathering 30-cm depth at sites where stone-weather Porter (1975a) with the Sherwin, Tahoe, and Tioga drifts rinds ing data collected. Measured rind thickness of the Sierra Nevada. Crandell (1965) to nearest 0.1 mm under magnification on summarized glacial-geologic studies in the 15 to 30 stones with best developed rinds Pacific Northwest and delineated the extent Degree of soil development of ice in the Oregon Cascades during the Profile Profiles were described from similar settings See discussion and references in last glaciation. His map shows a continuous development on moraine crests and high points on Birkeland (1974) ice cap extending from 30 km north of ground moraine; all soils are developed in Mount Jefferson to Mount Mcloughlin in till from andesitic source rocks. Noted southern Oregon, a distance of almost 300 horizon thickness, color, consistence, km; a small ice cap around Mount Hood; texture, structure, and boundaries and small valley and cirque glaciers near the Free iron oxide Used Jackson's (1969) citrate-bicarbonare Ugolini and Bull (1965), Mountain Lakes Wild Area and in the oxide and dithionite extraction and measured Fe on Jackson (1969, p. 44, 49- Western Cascades. Most recently, Carver hydroxide atomic absorption spectrophotometer. 51 ), Alexander (1974) (1972) completed a study of Cascade glaci content Determinations made on samples from ation south of Crater Lake and in the each horizon or at 20-cm intervals vicinity of the Mountain Lakes Wild Area. Using weathering characteristics of the TABLE 2. UNITS RECOGNIZED IN THE METOLIUS RIVER AREA drifts, he differentiated six Pleistocene drifts, a Neoglacial drift, and a variety of Geologic Glacial-stratigraphic units Rock-stratigraphic units Pleistocene and Holocene periglacial de time units posits. ..c u Till facies 0 Geologic Setting of the w0.. Jefferson Park Jefferson Park Outwash facies ., Holocene advance } formation Rock-glacier deposits High Cascades c:: } 1:l interglaciation } Protalus deposits 0 Forked Burte } Forked Burte formation Apparently the volcanic acnv1ty that 0 nonglacial interval formed the Oregon Cascade Range was :r: episodic. McBirney and others (1974) con Till facies cluded that four relatively short eruptive Canyon Creek Canyon Creek Outwash facies intervals occurred during Miocene, Late advance member Miocene-Early Pliocene, Pliocene, and Cabot Creek } Rock-glacier deposits Quaternary time. glaciation Protalus deposits Till facies The High Cascades are largely the prod Suttle Lake Suttle Lake Outwash facies advance member } uct of Quaternary volcanism and are com 1 Loess facies posed of three sequences of rocks. The ear liest flows of basalt, basaltic andesite, and Cabot Creek-Jack Creek interglaciation South Cinder Peak formation Till facies andesite form a platform of broad, over Jack Creek Jack Creek glaciation Outwash facies lapping shield volcanoes that make up the formation "· great bulk of the High Cascades (Thayer, lLoess facies 1939, p. 30; Williams, 1957; Taylor, 1968, Jack Creek-Abbott Burte Brush Creek formation p. 3 ). Pyroclastic rocks are volumetrically interglaciation insignificant compared with flows. The sec Abbott Burce glaciation Abbott Burte formation ond sequence, which forms the major Cascade Andesite formation stratovolcanoes, was built on the High Cas cade platform by explosive andesitic erup '' A formal stratigraphic unit, Jack Creek Formation, was defined by N. L. Taliaferro for some tions between 700,000 yr ago (McBirney, Upper Cretaceous shales and silts in west-central California. The same geographic name is used in this 1968) and the last major glaciation. The report because it is used locally and informally for sediments of Quaternary age and because the best exposures of this geographically restricted unit occur in the Jack Creek area. third sequence is composed mostly of basal- Jet fers9P.oht Pork w · EXPLANATION Qhf I J [ Oho Qhf I Holpc€ne oll~vium IQh,:i) and ;:'.' C.> boulttery flood deposits (Qhf) 0 C ~ Forked Butte formation C Q.) ~ Q.) ~ Lava flows and tephra. In Jefferson till C Q.) · Cr- Cabot Cr oreo designated 3 28 ~ Jefferson Pork (oldest) to I (youngest) 0 - r,:;=---i u outwosh 0 8~ ~ 0 - Mazama ash - formation I rock-glacier Cabot Creek formation !I ~ deposits I till ~ Canyon Creek ' \ ou twosh Tu I §c~l member rock- glacier ~ deposits Suttle Lake till member outwosh >-\,... 0 C \,... ~ South Cinder Peak formation 0 Lava flows and domes and tephro :::, Q.) Oc Q.) u till ~ [Ilfilill]!] Jock Creek a3 CL f.ai(:I formation outwosh Brush Creek formal ,on Lovo flows and domes &ii Abbott Butte formation ti ll ;,J ~ Volcanic rocks of the High Cascades ~ I ;:'.' ·..=0 Tertiary volcan ic and se dimentary racks ~I ~ Contact ,o u '- Fault = Sontiom Cinder cone = Poss 0 Mt Jefferson glaciers r Russell Glacier Ml 121°45' i Jefferson Pork Glac ier Jef!erso, WMewater wh Whitewa ter Glacier (1961) River (1961) w Waldo Gloc1er 4 4°30' T hre Sisters [;J Fingered (1959) LOCATION Jack (1959) Figure 2. Generalized surficial geologic map of the Metolius River area, Oregon. 116 W. E. SCOTT tic andesite and basalt of Holocene age and TABLE 3. REPRESENTATIVE SOIL PROFILES DEVELOPED ON TILL OF is readily identified by lack of glacial ero SUTTLE LAKE, JACK CREEK, AND ABBOTT BUTTE FORMATIONS sion. In the study area, this sequence is rep resented by scattered cinder cones and lava Horizon Depth Description flows, whereas farther south near the Three (cm ) Sisters there was greater Holocene vol Till of canism (Taylor, 1965). Suttle Lake m ember Al 0- 15 Dark brown (10 YR 3/2); pebbly, cobbly, sandy loam; massive, very fine STRATIGRAPHY OF GLACIAL crumb structure; nonsticky, nonplastic; clear, smooth boundary; AND PERIGLACIAL DEPOSITS many medium and fine roots Bs 15- 50 Dark yellowish brown (10 YR 4/4); pebbly, cobbiy, sandy loam; mas In order to differentiate glacial and peri sive, very fine crumb structure; nonsticky, nonplastic; gradual, glacial deposits in one valley and allow cor smooth boundary; many medium and coarse roots relation with similar deposits in adjacent Cox 50- 100 Dark grayish brown (10 YR 4/2); pebbly, cobbly, sandy loam; massive, valleys, several methods were used that very fine crumb structure; nonsticky, nonplastic; medium roots; dif have been applied successfully in other fuse, smooth boundary Cn 100- Very dark grayish brown (2.5 Y 3/2); pebbly, cobbly, sandy loam; glacial-geologic studies (Table 1). In this massive, very fine crumb structure; nonsticky, nonplastic study, differentiation and correlation of glacial deposits rely heavily on their weath Till of ering characteristics and degree of soil de Jack Creek formation velopment. Al 0-15 Dark brown (10 YR 3/2); pebbly, sandy loam; massive, fine crumb Evidence of at least five glacial advances structure; nonsticky, nonplastic; gradual, smooth boundary; many medium and coarse roots 2). occurs in the Metolius River area (Table B21s 25- 55 Medium brown (7.5 YR 4/4); pebbly, cobbly, sandy loam; massive, fine Glacial- and rock-stratigraphic names listed crumb structure; nonsticky, nonplastic; diffuse, smooth boundary; in Table 2 are used informally (Richmond medium and coarse roots and others, 1959, p. 666, 670). Following is B22t 55- 80 Medium brown (7.5 YR 4/4); pebbly, cobbly, sandy loam; weak, a description of deposits of each glacial ad medium crumb structure; slightly sticky, slightly plastic; gradual, vance, from oldest to youngest. smooth boundary; medium roots Cox 80-200 Dark yellowish brown (10 YR 3/4); pebbly, cobbly, sandy loam; mas Abbott Butte Formation sive, medium to coarse crumb structure; nonsticky, nonplastic; diffuse, smooth boundary; few fine and medium roots Cn 200- Very dark grayish brown (2.5 Y 3/2); pebbly, cobbly, sandy loam; The freshest till of the Abbott Butte for massive, very fine crumb structure; nonsticky, nonplastic mation consists of cobbles and boulders of varied andesitic lithologies in a compact, Till of light grayish-brown, sandy matrix. Expo Abbott Butte for111ati o11 sures of till occur along the new Jack Lake Removed Medium brown (7.5 YR 4/4); pebbly, cobbly, sandy loam; massive, road between two lateral moraines of Jack Bs 0- 45 medium crumb structure; nonsticky, nonplastic; gradual, smooth Creek age, on Abbott Butte Road south of boundary; many medium and coarse roots Brush Creek, and on the southeast side of B21tb 45-85 Dark reddish brown (5 YR 3/4); pebbly, cobbly, sandy loam; weak, Abbott Butte (Fig. 2), for which this drift is fine blocky structure; slightly sticky, slightly plastic; diffuse, smooth named. No outwash facies of the Abbott boundary; medium roots Butte formation has been recognized. B22tb 85-115 Reddish brown (5 YR 4/4); pebbly, cobbly, sandy loam; moderate, Till of Abbott Butte age is highly weath angular blocky structure; slightly sticky, slightly plastic; diffuse, ered. Stone-weathering ratios average smooth boundary; few medium roots 2:55:43 (weathered:partly weathered:to B23tb 115-170 Reddish brown (5 YR 4/4); pebbly, cobbly, sandy clay loam; moderate, tally weathered) (Fig. 3), and many stones medium angular blocky structure; sticky, plastic; few medium roots are so weathered as to be easily cut with a Note: Munsell colors were determined on moist samples. shovel. Weathering rinds as much as 1.5 mm thick are developed on fine-grained TOTALLY WEATHERED andesite, and mean rind thicknesses at seven sampling sites range from 0.8 to 1.0 mm (Fig. 4) . Mean 1.0 Thick, well-developed soils (Orthods, rind Brown Podzolic soils) have formed on till of 50% thickness the Abbott Butte formation. Due to limited mm 0.5 exposure of the till; the great thickness of the soil (several metres); thick cover of loess, tephra, and colluvium; and erosion; o-">..C,._,._"-"--..,._,. ______no complete soil profiles were observed. Cabot Ck Jack Ck Abbott Butte !rm trm trm However, several partial profiles as much as UN WEATHERED PARTLY 150 cm thick were available in roadcuts WEATHERED Figure 4. Weathering-rind thicknesses on • Till of Suttle Lake member and soil pits. In outcrop, the soil is very dis stones in tills. Each point represents one sam • Till of Jack Creek frm. pling site from which 15 to 30 stones with the tinctive owing to its reddish-brown color (5 • Till of Abbott Butte frm. best developed rinds were sawed and rinds mea YR 3/4, m). Thick clay skins on stones and Figure 3. Stone-weathering ratios of tills. sured. Error bars represent ± 1 standard devia blocky peds are present in all profiles and Each point represents a count of 40 to 185 cob tion from the mean. For Cabot Creek formation, indicate a greater degree of clay formation bles from the upper 30 cm of soil on moraine lined pattern shows range of rind thicknesses at than in any of the younger soils (Table 3). crests or on high points on ground moraine. eight sampling locations. QUATERNARY GLACIATION AND VOLCANISM, OREGON 117 Of the three profiles in which free iron con preserved. The moraines are best displayed which deposits of Jack Creek age were tent was measured, one shows a maximum neat Jack Creek (Fig. 2). A prominent left deeply buried by other glacial sediments, of 7.5 percent, while the others may have lateral moraine and hummocky terminal thin (<50 cm thick), discontinuous loess of their maxima at greater depth than could be moraine are analogous in form to the Jack Creek and Suttle Lake age covers till sampled in the exposure (Fig. 5). moraines of the Suttle Lake advance that and outwash of Jack Creek age near dam Suttle Lake. A smaller recessional moraines and outwash fans. However, the Jack Creek Formation moraine that lies about 1 km upvalley from loess has been churned into the underlying the terminal moraine indicates a stillstand rill or ourwash by tree fall and slope pro Till of the Jack Creek formation (see or readvance following the maximum of the cesses and usually does not form a distinct footnote, Table 2) is composed of subangu Jack Creek glaciation. Mass wasting has layer. Near the "Suttle Lake" cone, till of lar to subrounded cobbles and boulders in a modified lateral moraines so that they dis Jack Creek age is buried beneath the "Suttle compact, very dark grayish-brown (2.5 Y play broadly rounded crests. Proximal Lake" cone, Sand Mountain, and Blue Lake 3/2, 111) sandy matrix. Till is widespread on slopes rise at 8° to 15° and distal slopes at 5° tephras (Table 4). interfluves and, in some valleys, to 12°. Surface-boulder frequencies on downstream from moraines of the last moraine crests range from 4 to 14, with a Cabot Creek Formation glaciation (Fig. 2). The largest area of ex mean value of 7. posed rill is near Jack Creek, for which this Drift of Jack Creek age is oxidized to Cabot Creek valley, which contains drift is named. depths of 1.5 m to more than 2 m. Few prominent end moraines formed during the Outwash of Jack Creek age, which is stones are totally weathered, but most are maximum of the Cabot Creek glaciation, is composed of grayish-brown sand and pitted and stained. Stone-weathering ratios the type area for the Cabot Creek forma gravel near the Metolius River, becomes average 13:64:23 (Fig. 3). Weathering rinds tion, which has been subdivided into the bouldery near terminal moraines. Outwash are moderately common on stones and Suttle Lake and Canyon Creek members. terraces are best developed in valleys where reach thicknesses of 1.2 mm. Mean values Suttle Lake Member. The Suttle Lake there was a difference of several kilometres of 0.4 to 0.6 mm were measured at 15 sam member is named for Suttle Lake, which is in ice extent during the Jack Creek and sub pling sites (Fig. 4). dammed by a terminal moraine of the Suttle sequent Cabot Creek glaciations. In the val Soils formed on drift of Jack Creek age Lake advance. Nearby roadcuts along U.S. ley of Candle Creek, terminal moraines are are only weakly (Umbrepts) to moderately 20 expose bouldery rill with a compact, 3.5 km apart, and the outwash-rerrace sur (Orthods) developed compared with soils grayish-brown, sandy matrix, similar to faces are vertically separated by as much as developed on the Abbott Butte formation other till of Suttle Lake age exposed widely 8 111 (Fig. 2). Abandoned braided channels (Table 3). Compared with younger soils, over the study area (Fig. 2). Ourwash of the on the terrace tread contain boulders as they have a distinct color-B horizon from Suttle Lake member covers much of the much as 1 111 in diameter. In other valleys, 40 to 70 cm thick, which is more reddish floor of the Metolius River valley and forms where ice extents and meltwater-stream brown (7.5 YR 4/4, m) than B horizons of low terraces only a few metres above gradients were similar, if the surfaces are soils on drift of Suttle Lake age. In a few present streams. The ourwash is grayish to separated at all, the terrace scarps are only profiles, especially those at higher altitudes yellowish brown and very coarse grained a few metres high. where precipitation is greater, field exami and bouldery near end moraines, and it be The Jack Creek glaciation is the oldest nation revealed a slight plasticity when comes better sorted downstream, where it glaciation from which moraines are moist, suggesting some textural develop consists of sand, pebbles, and cobbles. ment of the B horizon as well. In seven soil Abandoned braided channels on the surface %Free iron oxides profiles on the Jack Creek formation, 2 to 3 of ourwash fans and terraces are readily 2 4 6 8 percent free iron oxide occurs in the B hori visible on aerial photographs and in the '00 zon, and iron enrichment extends to depths field. of 1.5 m or greater (Fig. 5). In most valleys there are one or more Although no exposures were seen in small recessional moraines upvalley from 40 - _ ·...,- , ' TABLE 4. HOLOCENE TEPHRA IN THE METOLIUS RIVER AREA, OREGON E ' _g 80 Source Description Distribution Age ' \ ..c ("Cyr) n. Q) Cone on south Black scoriaceous ash Rockpile and Cabot About 1,000''· 0 120 ' I \ flank of South and lapilli, bombs Lakes and South Cinder Peak near cone Cinder Peak 160 ~ Blue Lake crater Coarse scoria, black ash Suttle Lake, First Creek 3,440 ± 250 (Taylor, and lapilli, accidental 1965, p. 137) fragments W Soils developed on till of: 200 Little older than 3,440 ~ Suttle Lake member Sand Mountain Black scoriaceous ash Suttle Lake, First Creek, (Taylor, 1965, p. 13 7) EZa Jack Creek formation alignment Canyon Creek --- _ Abbott Butte formation Forked Butte Several nearly con Carl Lake/Cabot Lake 6,400 to 6,500* individual profiles temporaneous layers, cirque, Jefferson black scoriaceous ash, Lake, Patsy Lake, Figure 5. Percentage of free iron oxides in re and cinders Table Lake lation to depth in soils developed on till of Suttle Lake, Jack Creek, and Abbott Butte formations. Mount Mazama 15-cm-rhick ash and Throughout area, best 6,640 ± 250 (Rubin and For soils developed on till of Suttle Lake and Jack (Crater Lake) lapilli, white-gray to preserved in lakes, Alexander, 1960, Creek age, dashed lines represent mean values for yellowish-orange meadows, and cirques p. 116) six profiles, and pattern covers range of values ,:- Dare determined from sedimentation rate in Cabot Lake. for given depth in soil. 118 W. E. SCOTT Brush - --Qlt A. 500- - -0 500 1000 I Metres ...... ______, moraine crest Figure 6. Terminal and recessional deposits of the Suttle Lake advance in (A) Brush Creek valley and (B) Cabot Creek valley. Qfv = Forked Butte formation; QII = lacustrine deposits, Qlt = till (1, oldest, to 3, youngest), and Qlo = outwash of Suttle Lake age; Qjt = till and Qjo = outwash of B. Jack Creek age; Qbv = Brush Creek formation; and Qat = till of Abbott 500 0 500 1000 Butte age. Metres the large terminal moraine deposited at the moraines of subsequent advances indicate a 3/2, 111 ) till or ourwash. These young soils maximum limit of the Suttle Lake advance. period of recession between advances. are very granular and stony, except where In Cabot Creek valley, two moraines lie Crosscutting relationships are well dis developed on fine alluvium. Commonly, the within the right-lateral moraine (Fig. 6B). played in Candle Creek, Brush Creek, Jack upper 50 cm of soil contains a high propor Weathering characteristics indicate that Creek, and Canyon Creek valleys. Here, tion of silt and sand where loess has been these moraines are all approximately the moraines of Suttle Lake age partly bury or churned into the underlying till or ourwash same age and are recessional moraines built truncate moraines of Jack Creek age (Figs. by tree fall. In the southern part of the area during standstill or readvance. The Forked 2, 6A, 6B ). Typically, lateral moraines of and near Forked Butte, this soil has been Butte la';a flow has covered any recessional Suttle Lake age have proximal slopes of 20° buried by local rephra on which thin (<50 moraines present on the valley floor. There to 28° and distal slopes of 5° to 22°. Termi cm thick) A/Cox profiles have formed. are also two recessional moraines in Brush nal moraines generally have less steep The maximum value of free iron oxides Creek valley (Fig. 6A); the first is set just slopes than their corresponding lateral for five soils on rill of rhe Suttle Lake within the large end moraine; the second (4 moraines. The moraines also have sharp member is slightly more than 2 percent, and to 5 m high) forms a nearly complete loop bouldery crests and surface-boulder fre below a depth of 1 m, values are usually less across the valley floor, breached by Brush quencies ranging from 12 to 41. than 0.5 percent (Fig. 5 ). Samples with 0.5 Creek on the south side. A small ourwash Very few stones in drift of Suttle Lake age percent free iron oxide appear fresh, with fan is graded to the moraine surface. In are totally weathered. Almost half the only sparse, yellowish-brown stain on par Cabot Creek, Brush Creek, and Canyon stones are fresh, and stone-weathering ticles and cracks. The freshest rill of Suttle Creek valleys, Bear Valley, and at Suttle ratios average 45 :51 :4 (Fig. 3). Weathering Lake age that was sampled contained about Lake, the recessional moraine or moraines rinds are scarce and where developed are 0.3 percent free iron oxides (Fig. 5). lie within 2 km of the terminal moraine. In discontinuous and have a maximum thick Canyon Creek Member. Deposits of the First Creek valley, evidence of recessional ness of only 0.2 mm (Fig. 4). Canyon Creek member are restricted ro stands is lacking. Since the number of Soils formed on deposits of Suttle Lake cirques and valley heads near the Cascade moraines near the maximum position of age are typically thin and weakly developed crest and stratovolcanoes and have been glaciers during the Cabot Creek glaciation (Table 3). Wherever observed, these soils subdivided into four facies : rill, ourwash, is nor identical in all valleys and no data, are less than 1 m thick. An A horizon of rock-glacier deposits, and proralus depos except for position, allow correlation of in variable thickness (0 to 20 cm) overlies a its. Lodgment till of Canyon Creek age dividual moraines between valleys, no sub poorly developed and defined color-B hori looks identical to rill of the Surtle Lake division has been attempted. The moraine zon (10 YR 4/3, m) 25 to 40 cm thick. A member but is poorly exposed because or moraines near the maximum are referred slight color change is all rhar distinguishes most of the outcrops are shallow and ex to rhe Suttle Lake advance of the Cabot the lower B from rhe Cox horizon, which is pose only ablation till, which is composed Creek glaciation. 30 to 60 cm thick and composed of of cobbles and boulders in a loose, In many valleys, moraines exhibit yellowish-brown ( 10 YR 4/2, m), slightly grayish-brown, sandy matrix. ear crosscutting relationships. Older moraines weathered parent material. Below the Cox moraines, ourwash of Canyon Creek age is that are partly buried or truncated by lies fresh, very dark grayish-brown (2.5 Y bouldery and poorly sorted, and it grades QUATERNARY GLACIATION AND VOLCANISM, OREGON 119 I Qiu I ) ... / c"' \ , ..,. \ OI i 2390' m Three Mt. Fingered Jock \ N Qiu N 500 0 500 1000 1500 Metres 0 Summit Lake B. 500- --0 500 1000 1500 A. Metres Figure 7. Deposits of the Canyon Creek and Jefferson Park advances on (A) Three-Fingered Jack and (B) Mount Washington. Qhc = Holocene col luvium; Qpt = till, Qpo = outwash, and Qpp = protalus deposits of Jefferson Park age; Qct = till (1, older, 2, younger), Qco = outwash, Qcr = rock glacier deposits, and Qcp = protalus deposits of Canyon Creek age; Qlt = till of Suttle Lake age; and Qvu = volcanic rocks of the High Cascades. downstream into moderately well sorted mafic tephra (Table 4) and therefore are gentle (6° to 8°) front resembles that of in sand and gravel. Moraines are sharp probably latest Pleistocene or early active rock glaciers described by Wahrhaf crested, have steep (::s 28°) sides, and are Holocene in age. tig and Cox (1959) from the Alaska Range. typically bouldery, with surface-boulder The moraines in Canyon Creek cirque The deposit has a "deflated" appearance frequencies greater than l 00. Most stones have been subdivided into phases 1 and 2 caused by melting of the core of glacier ice. are fresh, and weathering rinds, if present, (Fig. 2, 7 A). Phase 1 deposits include termi Similar glacier-rock-glacier transitions are are less than 0.2 111111 thick and discontinu nal and lateral moraines in Canyon Creek found in George Lake and Dry Creek ous. Soils on the drift are thin and imma Meadows. By phase 2, the glacier had re cirques on Mount Washington (Fig. 2, 7B ). ture, similar to soils formed on the Suttle treated and split to form two small glaciers The north- and northeast-facing cirques on Lake member. Near Three-Fingered Jack, (Fig. 7 A). A 25-m-high end moraine with Mount Washington contained glaciers dur deposits of slightly weathered Holocene an outwash fan graded to it, now incised by ing both phases 1 and 2, as in Canyon tephra as much as 1 111 thick bury this soil. Canyon Creek, was built in the main valley. Creek cirque. End moraines are well displayed in the A smaller end moraine was formed in the During the Canyon Creek advance, Canyon Creek cirque on Three-Fingered tributary cirque to the southeast. snowbanks and frost action helped form Jack (Figs. 2, 7A). A terminal moraine 3 to In First Creek cirque on Three-Fingered protalus ramparts (Figs. 7 A, 7B), which are 6 111 high lies at the east end of Canyon Jack (Fig. 7 A), phase 1 is represented by a best displayed along the south side of Cabot Creek Meadows. West of here, for a dis low terminal and right-lateral moraine. Creek valley and the north side of Brush tance of 1.5 km, a series of loop moraines, During phase 2, the glacier, covered with Creek valley. The deposits form linear to some of which show intersecting relation debris from the steep headwall, became a lobate ridges, up to 3 111 high, of large, an ships, indicates an interval of stillstand and rock glacier. The rock-glacier deposit is lo gular blocks as much as 3 111 in diameter. readvance late in the retreat of the glacier bate, and faint furrows are visible on aerial Typically, the blocks are almost completely from its maximum during the Suttle Lake photographs; its surface is now covered covered with lichens (primarily Rhizocar advance. The deposits are covered with with as much as 1 111 of tephra, which sup pon geographicum, s. I., and a black foliose Mazama ash and younger, local, more ports meadow vegetation. The low (3 m) lichen). In some places thick accumulations 120 W. E. SCOTT of tephra or loess support forests. On north-facing slopes, the deposits range from Jefferson altitudes of 1,500 to 1,800 m, whereas on Pork south-facing slopes they occur near \ 1,700 m. I I Jefferson Park Formation Deposits of the Jefferson Park advance occur in cirques on Mount Jefferson and Three-Fingered Jack; they include till and Qtu outwash near termini of present glaciers and rock-glacier and protalus deposits (Figs. 2, 7 A, 8). The formation is named for Jefferson Park Glacier, which deposited conspicuous lateral moraines during this advance. Glacial sediments observed in Canyon Creek cirque on Three-Fingered Jack in N clude ablation till and outwash (Fig. 7 A). The ablation till, which is bouldery and very poorly sorted, contains more angular stones than the older drifts. This is proba bly due to the short (400-m maximum) length of transport from the 500-m-high headwall. The steep, unstable moraine Mt. dams a small lake and has a proximal slope Jefferson of about 42°. The slope has numerous wet landslide scars that suggest melting of an ice core. The outwash forming the fan behind 500 0 500 1000 the phase 2 Canyon Creek moraine is com Metres posed of moderately well sorted sand and gravel. Deposits of Jefferson Park age are sparsely vegetated with small trees, scat tered lichens (Rhizocarpon geographicum, moraine crest s. I., up to 34 mm in diameter), and her baceous plants. The drift is unoxidized, and moraines and till surfaces are very fresh, Figure 8. Deposits of the Otu Jefferson Park advance on bouldery, and unstable. A few boulders are Mount Jefferson. Qhc = slightly weathered, but none display weath Holocene colluvium; Qpt = till ering riQds. No tephra (Table 4) has been (1, older, 2, younger), Qpo = found on any of the moraines of the Jeffer outwash, and Qpr = rock son Park advance. glacier deposits of Jefferson On the south slopes of Canyon Creek Park age; Qtu = older till, in and First Creek cirques, small, lobate pro cludes some bed rock; Qsv = talus ramparts, 2 to 3 m high, occur at an South Cinder Peak formation; altitude of about 1,900 m (Fig. 7 A). They and Qvu = High Cascade vol canic rocks. are composed of angular boulders as much as 3 m in diameter and have a sparse lichen (<20 mm) scattered Rhizocarpon geo turies, and its drift is equivalent to Carda cover of Rhizocarpon geographicum, s. I., graphicum, s. I., and herbaceous plants. Drift on Mount Rainier (Crandell, 1969; up to 30 mm in diameter. The age of the oldest mountain hemlock, Crandell and Miller, 1974) and other late On Mount Jefferson, two phases of the Tsuga mertensiana, growing on the Neoglacial drifts in western North America Jefferson Park advance are recognized (Fig. moraine of Jefferson Park age in Canyon (Porter and Denton, 1967). 8). During phase 1, end moraines as much Creek cirque is 90 yr. Hemlocks of about as 50 m high were built by the glaciers. As the same age are growing on the moraines Chronology on Three-Fingered Jack, the moraines are on Mount Jefferson near Russell Creek, steep, unstable, and bouldery. Some are ice whereas trees in the mature forest beyond In order to help place the possible ages of cored. They are sparsely vegetated except this moraine are several hundred years old. glaciation in the Metolius River area in near Russell Creek, where moraines lie Also, tephra from the eruption of the cone perspective, Figure 9 shows a range of cor below timberline and support small trees. on the south flank of South Cinder Peak, relations between the oxygen isotopic rec Phase 2 moraines lie less than 1.5 km upval which occurred about 1,000 yr or less ago ord from the equatorial Pacific (Shackelton ley from phase 1 moraines and very close to (Table 4), does not cover the moraine of and Opdyke, 1973) and the glacial record the termini of existing glaciers. The Jefferson Park age in Canyon Creek cirque in the Metolius River area that seems com moraines of phase 2 are smaller than phase although it lies on the moraine of Canyon patible with current understanding of the 1 moraines, sharp-crested, steep, and un Creek age adjacent to it. Apparently, the ages of glaciations in the Pacific Northwest. stable. They are above timberline and advance that deposited the Jefferson Park The distribution, morphology, and barren of vegetation except for small formation occurred in the past few cen- weathering characteristics of drift of Cabot QUATERNARY GLACIATION AND VOLCANISM, OREGON 121 Creek age are similar to those of other late between Jack Creek and Cabot Creek plosive, because much tephra is exposed in Wisconsin alpine drifts in the northwestern glaciations was shorter than that between their eroded flanks. United States. Drift of the Suttle Lake the· Abbott Butte and Jack Creek gla During the Jack Creek-Abbott Butte in member is correlative to Waban drift in the ciations. terglaciation, there was local andesitic vol southern Oregon Cascades (Carver, 1972), Deposits of Jack Creek age have a similar canism in the Mecolius River area (Fig. 2). Evans Creek Drift at Mount Rainier (Cran morphology and degree of weathering and In this study, rocks formed during this dell, 1969; Crandell and Miller, 1974), and soil formation to Hayden Creek Drift at interval are assigned to the Brush Creek pre-Hyak members of Lakedale Drift in the Mount Rainier (Crandell and Miller, 1974, formation. Just west of Abbott Butte, near southern North Cascades of Washington p. 21-22) and Kittitas Drift in the Wash the mouth of Brush Creek valley, (Porter, 1976). The Suttle Lake advance of ington Cascades (Porter, 1976), although cumulophyric andesites were erupted along Cabot Creek glaciation is broadly equiva the areas display great climatic differences an 800-m-long fissure forming three blocky lent in age to the advances that deposited and there is by no means close agreement domes, the largest about 80 111 in diameter these drifts. The Canyon Creek member between all weathering parameters. Cran and 20 111 high. The rocks show no sign of deposited during a late readvance of Cabot dell and Miller (1974, p. 55) tentatively glacial erosion, and no erratics were found, Creek glaciation is probably equivalent in considered Hayden Creek Dri fr to be even though the area was covered by Ab age to Zephyr Lake drift in southern Ore 40,000 to 80,000 yr old (early Wisconsin), bott Butte ice; thus, they must postdate the gon (Carver, 1972), Glacier Lake deposits although it may possibly be older. Porter Abbott Butte glaciation. In addition, low in the Wallowa Mountains (Kiver, 1974), (1976, p. 74) regarded Kittitas Drift as saddles along the fissure were breached by McNeeley Drift at Mount Rainier (Cran pre-Wisconsin or, less likely, early Wiscon meltwater streams of Jack Creek age and dell, 1969; Crandell and Miller, 1974), and sin in age. Jack Creek glaciation probably covered with outwash, thus stratigraphi the Hyak Member of Lakedale Drift in the dates from either of the high ice-volume cally bracketing the age of eruption. A rem Washington Cascades (Porter, 1976). intervals between 40,000 and 80,000 yr nant of an intracanyon andesite flow more For deposits of pre-Cabot Creek age, ago or 120,000 and 200,000 yr ago indi than 60 m thick forms a conspicuous bench weathering and other criteria will only cated in Figure 9. on the north side of upper Cabot Creek val allow general speculation as to their ages. The modification of deposits of Abbott ley (Fig. 2). The flow has well-developed Drift of Jack Creek age displays a greater Butte age is so great compared with columnar and platy jointing. The lava is degree of modification of form, weathering, modification of deposits of Jack Creek age similar to rocks exposed on the east side of and soil development (Figs. 3 to 5, Table 3) as to require several hundred thousand North Cinder Peak and probably originated than drift of Cabot Creek age; weathering years. The Abbott Butte glaciation may cor there. No stratigraphic evidence was found rinds are common and well developed respond to any (or several?) of the high to prove that this flow postdates the Abbott (about 0.5 mm thick), soil hues are redder ice-volume intervals between 200,000 and Butte glaciation; however, by its position in (7.5 YR versus 10 YR); there is greater and 900,000 yr ago. It seems unlikely, although a former glacial(?) valley, degree of erosion, deeper accumulation of free iron in the soil; remotely possible, that Abbott Butte glacia and degree of erosion of its probable source and there is evidence of some textural de tion is as young as 120,000 to 200,000 yr. (North Cinder Peak), the inferred age ap velopment of B horizons. In comparison the In the future, more precise age determina pears reasonable. differences in weathering characteristics be tions may be possible through radiometric During the Cabot Creek-Jack Creek in tween drift of Abbott Butte age and Jack daring of the interglacial volcanic rocks. terglaciation, "Suttle Lake" cone (Fig. 2) Creek age are even more striking. Soils de erupted tephra that covered rill of Jack veloped on the Abbott Butte formation con STRATIGRAPHIC RELATIONSHIP Creek age. The fact that the left-lateral tain several times as much free iron and OF QUATERNARY VOLCANIC moraine formed during the Suttle Lake ad display a much greater textural develop AND GLACIAL DEPOSITS vance adjacent to the cone is not covered by ment of B horizons. Since soil formation scoria or bombs from the eruption indicates and weathering probably progress at de Most of the High Cascade platform and that the cone was formed during the in creasing rates through time (Birkeland, srratovolcanoes were probably formed terglaciation. A shallow crater still remains 1967, p. 85, 1974, p. 176; Yaalon, 1971, p. prior to the Abbott Butte glaciation. Al on the summit, and quarrying has exposed 32), the time since the Abbott Butte glacia though exposures of Abbott Butte till are thin lava flows near the crater rim, but ap tion is probably much greater than the time few and highly weathered, lirhologically the parently no extensive lava flows were since the Jack Creek glaciation. The smaller rill contains clasts of most rock types ex erupted. The "Cinder Pit" (Taylor, 1965, p. difference in weathering and soil develop posed in the study area. However, in a ter 124), just east of "Suttle Lake" cone, was ment between the Jack Creek and Cabot rain of such similar rock types, this infor also probably formed during this in Creek formations suggests that the interval mation is of little value. Because parches of terglaciation. Most of the cone has been ex till of Abbott Butte age locally lie on slopes cavated for road metal, bur a small blocky ? - _ .. ___ AB ____ .... _ of the shield volcanoes that form the High lava flow remains east of the pit. Till of JC . cc .. ·- Cascade platform, the Abbott Butte glacia Jack Creek age underlying the cone was tion is regarded as younger than most of the oxidized during the eruption. ~ --~ ~~t platform. Highly dissected stratovolcanoes, The following volcanic features are also 0 20 0 400 600 800 such as Mount Washington and Three regarded as part of the South Cinder Peak 103 YEARS B.P. Fingered Jack, may also date from pre formation, which includes the eruptive Figure 9. Correlations between oxygen Abbott Butte time. Because Mount Jeffer products of the Cabot Creek-Jack Creek isotopic record of core V28-238 (Shackelton and son is less dissected than either of these vol interglaciation. However, firm stratigraphic Opdyke, 1973) and the Quaternary glacial rec canoes, it may be partly younger than the evidence is lacking. The main criterion, al ord in the Metolius River area that seem compat ible with current understanding of glacial Abbott Butte glaciation. Evidently, the though not a very satisfactory one, for as chronology in the Pacific Northwest. CC = main activity of the shield volcanoes was signing the deposits to this formation is de Cabot Creek glaciation, JC = Jack Creek glacia eruption of basaltic to andesitic lava flows, gree of erosion. South Cinder Peak is a tion, AB = Abbott Butte glaciation. Solid lines for few tephra layers are associated with 400-m-high cinder cone that lies on the correspond to times of high ice volume as in them. Later eruptions that formed the Cascade crest. Glacial erosion on the north ferred from the oxygen isotopic record. stratovolcanoes must have been more ex- side has exposed the conduit and several 122 W. E. SCOTT dikes, but the degree of erosion has not Other Holocene volcanism occurred west were quire different. (The Jack Creek area been great enough to suggest that the cone of Santi;rn1 Pass. Shortly before 3,500 14C yr is physiographically a "divide" between the has been glaciated more than once. The ago, a tephra eruption from Sand Mountain better defined valleys of First and Canyon Table (Fig. 2), a dome complex composed alignment spread as much as 90 cm of black Creeks.) Deepening of valleys and cirques of three overlapping domes (Brian Gannon, ash over t~e Suttle Lake area (Taylor, 1965, during the Jack Creek glaciation and Cabot 1973, written commun.), occupies the floor p. 136-137, 1968, p. 27), some 20 cm in Creek-Jack Creek interglaciation (which of a cirque that was excavated prior to the Canyon Creek cirque, and 1 cm in Cabot may have included several less extensive Cabot Creek glaciation, since the surface of Lake. At Blue Lake crater shortly after glaciations) probably caused glaciers of The Table was scoured by ice during the 3,440 14C yr ago, an explosion deposited Cabot Creek age to be funneled down val Suttle Lake advance. Because it is not ex accidental fragments, bombs, and scoria leys rather than spread out over broad, tensively eroded, The Table is tentatively around the crater (Taylor, 1965, p. 132) low-relief divides as during the Jack Creek assigned to the South Cinder Peak forma and a coarse, 50-cm-thick scoria layer over glaciation. tion. Other cinder cones and lava flows of 70 cm of Sand Mountain tephra on the the South Cinder Peak formation occur on left-lateral moraine damming Suttle Lake. Equilibrium-Line Altitudes of the southeast flank of Mount Jefferson The most recent eruption occurred on the Existing and Former Glaciers (cone 7,086 fr); just south of The Table, south flank of South Cinder Peak about where an eroded cone and flow are partly 1,000 14C years ago and formed a cinder The equilibrium line is rhe boundary be buried by a Holocene cinder cone, and cone and lava flow (Fig. 2, Table 4). tween areas of net accumulation and net north of Mount Jefferson near Ollalie ablation on a glacier (Paterson, 1969, p. Butte. These features are similar in degree CHARACTERISTICS OF 31). The equilibrium-line altitude (ELA) is of erosion; pressure ridges are still discerni QUATERNARY GLACIERS determined by several climatic and topo ble, although the flow surfaces are discon graphic factors, including temperature, pre tinuously covered with rill and cinder cones Extent of Former Glaciers cipitation, and exposure. lf the ELAs of are ice eroded. former glaciers can be calculated and com In the study area, no evidence of intragla Several methods were used to delineate pared with those of existing glaciers, as cial eruptions (ruyas, ice-chilled flow mar the areas covered by former glaciers. Obvi pects of past climates can be inferred. gins) has been observed. Recent evidence ously, the position of lateral and terminal Although no derailed mass-balance mea suggests that full interglaciarions and full moraines is the best criterion, at least below surements have been made on glaciers in glaciations were only brief intervals during rhe altitude of past equilibrium lines where the study area, several methods allow esti the past 500,000 yr (Emiliani, 1972). deposition predominated. Moraines are mation of current ELAs. If present glaciers Therefore, during most of Pleistocene time best developed in the lower valleys and on are in a steady-state condition, they should ice cover was probably limited (in the study some broad divides. In areas where have accumulation area ratios (AAR; ratio area, perhaps similar to ice cover during the moraines are nor well displayed, distribu of accumulation to total area) between 0.5 Canyon Creek advance), and rhe probabil tion of rill and its weathering and soil and 0.8 (Meier and Post, 1962, p. 70). ity of an eruption coming in contact with characteristics provide helpful information. ice was small. It is also possible that intra In areas where the dominant process was glacial volcanism did occur, however, bur erosion, the best evidence of upper ice limits evidence for it has either b;::en incorrectly is (l) the top of truncated spurs and (2) the interpreted or eroded or buried during sub boundary separating glacially smoothed sequent ice advances or volcanic eruptions. bed rock from sharp, rugged areas rhar Holocene volcanic activity between the stood above the surface of rhe glaciers and Three Sisters and Three-Fingered Jack has experienced intense frost action. covered hundreds of square kilometres with Little is known of the extent of glaciers of tephra and lava flows (Taylor, 1965, 1968). Abbott Butte age because of the few expo During the same time in the Metolius River sures of till. Till is largely restricted to area, volcanism has been more local than interfluves, and no exposures are known farther south (Fig. 2). All the deposits post downstream from moraines of Jack Creek date the eruption of Mount Mazama, about age; however, rill of Abbott Butte age may 6,600 14 C yr ago (Rubin and Alexander, be buried by younger ourwash. On some 1960, p. 161; Table 4). divides there is evidence that glaciers of Forked Butte, a 150-m-high cinder cone Abbott Butte age were more extensive than after which the Holocene volcanic rocks are later glaciers (Fig. 2). However, this may be named (Forked Butte formation), erupted due to valley deepening since the Abbott about 6,400 to 6,500 14C yr ago (Table 4). Butte glaciation, which did not permit the Black scoriaceous tephra and two basaltic ice to rise as high on the interfluves during andesite lava flows (Fig. 2) were probably subsequent glaciations. erupted nearly contemporaneously, because The extent of glaciers during the last two there is no break in the sequence of Forked major glaciations is better known. Figure Butte tephra in a core from Cabot Lake. 10 shows the reconstructed maximum ex Following the younger Forked Butte erup tent of glaciers during the Jack Creek and tion, "Horseshoe" cone, a breached cone Cabot Creek glaciations. East of the Cas on the south side of Bear Butte, erupted. Its cade crest, between Sanriam Pass and lava dammed Jefferson Lake, flowed down Mount Jefferson, there was about 30 per Figure 10. Extent of glaciers during Cabot the Jefferson Creek valley past the terminus cent greater ice cover during the Jack Creek Creek glaciation (contoured surface) and Jack of the Forked Butte flow in Cabot Creek glaciation. Generally, the extent of glaciers Creek glaciation (lined pattern). Stippled areas valley, and then flowed down Candle Creek in valleys during the two glaciations was represent probable nunataks during Cabot Creek valley, a distance of 13 km (Fig. 2). similar, whereas ice extents on divide areas glaciation. QUATERNARY GLACIATION AND VOLCANISM, OREGON 123 However, Meier and Post (1962, p. 74) ob glaciation (Fig. 11 ), although some of the glaciers during this time were restricted to served that glaciers in the Oregon Cascades lowest cirques may have been formed dur areas near the Cascade crest, and the ELA were retreating in the early 1960s. Com ing a previous glaciation and were not reoc gradient was probably perpendicular to the parison of photographs taken in 1937 cupied during the Cabot Creek glaciation. trend of the crest as during the Suttle Lake (Mazamas, 1938) and the 1960s indicates Presumably, higher precipitation in the advance. The mean value for steady-scare that termini have retreated several hundred western portion of the range permitted ELAs, 1,810 ± 30 m, is plotted in Figure metres on Mount Jefferson and that Collier glaciers to exist at lower altitudes than 11. During the Canyon Creek advance, Glacier on Middle Sister has retreated farther east. The distribution of individual ELAs were approximately 250 m higher about 1,400 m. ln 1961, glaciers in the ELAs in Figure 11 defines the regional than those during the Suttle Lake advance. Oregon Cascades had AARs of about 0.4 snowline (Flint, 1971, p. 64), which lay This difference from present ELAs of 700 to (Meier and Post, 1962, p. 71). With an within an altitude band of about 200 m and 750 m is close to that calculated for late AAR of 0.4, ELAs for Mount Jefferson rose eastward at 5m/km. A steeper rise in readvances during the last glaciation glaciers are 2,570 m on the west side and southern Oregon, 10.3 m/km, was calcu elsewhere in the Cascades (Carver, 1972; 2,660 m east of the crest. This gradient lated by Carver (1972, p. 70) by using simi Porter, 19756, p. 45). probably reflects precipitation differences lar techniques, Orographic effects similar to late-glacial between the windward and leeward flanks In the High Cascades, the ELAs of valley and present-day conditions also existed of the mountain. glaciers and sections of the ice cap define a during the Jefferson Park advance. An ELA Another way of estimating ELAs is by de regional ELA gradient of 14 m/km (Fig. 11), of about 2,400 m, 200 to 250 m lower than termining the average altitude of the annual much steeper than in the Western Cascades. present, is shown in Figure 11 for Mount snowline (Flint, 1971, p. 36-37) over a This steeply rising regional snowline prob Jefferson glaciers. ELA gradients during the period of years. Photographs taken by Aus ably reflects an abrupt decrease in precipita Jefferson Park advance and at present show tin Post of the U.S. Geological Survey pro tion eastward, across the Cascade crest, and similar, steep gradients of 36 m/km vide this information for the 1960s and the orographic effect of the major vol eastward. early 1970s. The mean firn-limit altitude canoes, which is similar to the present pre Ice extents are roo poorly known during during this time for Whitewater Glacier on cipitation pattern. An even steeper gradient the Jack Creek glaciation to estimate an the east side of Mount Jefferson was 2,650 (>38 m/km) must have existed east of the ELA by the above method. However, by m, which is approximately the same as the range, because Black Butte (1,963 m), using the relationship between lowering of ELA calculated by using an AAR of 0.4. which lies 10 km east of the crest and is a ELA and ice-covered area during sub Median glacier altitude, 2,600 m for volcano formed prior to the Cabot Creek sequent glaciations, a minimum estimate west-side Jefferson Park Glacier and 2,675 glaciation, shows no evidence of having for ELAs during the Jack Creek glaciation m for Whitewater Glacier, is also compara been glaciated. This further suggests an is 1,100 to 1,150 m beiola, present-day ble with the previous values for the ELA. abrupt decrease in precipitation due to both ELAs (Fig. 12). This differe~ce in ELA be The approximate vertical and horizontal the high precipitation over the 80-km-wide, tween present glaciers and glaciers during extent of former glaciers during the Suttle glacier-covered area in the Cascades and the Jack Creek glaciation also agrees closely Lake advance can be delineated (Fig. 10) the pronounced rain-shadow effect farther with values from the southern Oregon Cas using geologic information from surficial east. cades and the Washington Cascades for deposits and erosional landforms. As noted, When present ELAs of glaciers on Mount broadly correlative glaciations (Carver, most modern glaciers in a steady-state con Jefferson are compared with ELAs during 1972; Porter, 19756, p. 45 ). The shape of dition have AARs between 0.5 and 0.8 . The the Suttle Lake advance, a difference of the curve in Figure 11 is largely determined ELAs of former glaciers can therefore be es about 950 m is evident (Fig. 11 ). This dif by the local area-altitude distriburion timated, assuming they also had steady ference is a minimum value because present (Porter, 1970, p. 1445). Ar present, small state'AARs of 0.5 to 0.8. ln this study ELAs glaciers occupy protected cirques and dis lowerings of the ELA will nor result in were estimated by using an AAR of 0.6 ± play great variations in amount and altitude greatly expanded glaciers because lirrle area 0.1. Porter (1970, p. 1444, 19756, p. 35), of accumulation, whereas the ice cap during lies at high altitudes. With the ELA on the Andrews and Miller (1972, p. 46), and the Suttle Lake advance was almost fully lower, eastern slopes of the High Cascades, Carver (1972, p. 66-68) have used similar exposed to insolation and moist air masses. the opposite is true; small changes in the AARs in calculating past ELAs in Pakistan, A minimum ELA lowering of 950 m gener ELA will greatly affect ice cover because a New Zealand, the Pacific Northwest, and ally agrees with estimates from other areas large area is contained in a narrow alritudi the eastern Canadian Arctic. in the Pacific Northwest (Carver, 1972; nal zone. The relatively constant slope of On this basis, the cirque and valley Porter, 19756, p. 45). the High Cascades in the 1,200- to 1,800-m glaciers in the Western Cascades had ELAs ELA gradients for the Canyon Creek ad zone makes the projection of the curve in as low as 1,000 m during the Cabot Creek vance cannot be calculated, because all Figure 12 reasonable. -o- - - Existing glaciers 11. Calculated 0 • PRESENT -o - - - Jefferson Pork advance ◄ Figure equilibrium-line altitudes for Canyo n Creek advan ce \ MT. JEFFERSON 3000 late Quaternary glaciers in JEFFERSON PARK - • - --suttle Lake adva nce 1~_,-36 m/km north-central Cascade Range, E /.S:,,..- --36m/km Oregon. Points represent ELAs -400 ,6. _,-f __ _,,,-' >38m/ km for individual glaciers, assum 2000 WESTERN CASCADES ing accumulation area ratio of ELA (m) 0 CANYON CREEK ~6_. - ► -800 Figure 12. Relationship be ~UTTLELAKE tween lowering of equilibrium • - - - .... . JACK line altitude and ice-covered CREEK area. Present equilibrium-line - 1200+0-~-I0,----0--,---2-,0-0-,---3,--o-o 0 20 40 60 80 100 altitude for Mount Jefferson 2 DISTANCE EAST OF 122° 40' W km glaciers is about 2,650 m. ICE-COVERED AREA (km ) 124 W. E. SCOTT ACKNOWLEDGMENTS --1969, Surficial geology of Mt. Rainier Na Richmond, G. M., and others, 1959, Application tiot)al Park, Washington: U.S. Geol. Survey of stratigraphic classification and nomen I am grateful to S. C. Porter and A. L. Bull. 1288, 41 p. clature to the Quaternary: Am. Assoc. Pe Washburn for their advice and guidance as Crandell, D. R., and Miller, R. D., 1974, troleum Geologists Bull., v. 4,3, p. 663- Quat)rnary stratigraphy and extent of chairmen of my supervisory committee at 675. glaciation in the Mt. Rainier region, Wash Rubin, Meyer, and Alexander, Corrine, 1960, the University of Washington. I also thank ington: U.S. Geol. Survey Prof. Paper 847, U.S. Geological Survey radiocarbon dates F. C. Ugolini, who reviewed and construc 59 p. V: Am. Jour. Sci., radiocarbon suppl., v. 2, tively criticized preliminary drafts of the Dutton, C. E., 1889, Report of Capt. C. E. Dut p. 129-185. dissertation from which this paper was pre ton: U.S. Geol. Survey 8th Ann. Rept. Russell, I. C., 1905, Preliminary report on the pared. Thanks to H. A. Coombs and Minze (1886-1887), p. 156-165. geology and water resources of central Ore Stuiver, who also served on the supervisory Emiliani, Cesare, 1972, Quaternary hypsither gon: U.S. Geo!. Survey Bull. 252, 138 p. committee. mals: Quaternary Research, v. 2, p. 270- Shackelton, N. J., and Opdyke, N. D. , 1973, This manuscript benefited from review 273. Oxygen isotope and paleomagnetic stratig Flint, R. F., 1971, Glacial and Quaternary geol raphy of equatorial Pacific core V28-238: by P. E. Carrara, C. D. Miller, and T. J. ogy: New York, John Wiley & Sons, Inc., Oxygen isotope temperatures and ice vol Andrews and from discussions with K. L. 892 p. umes on a 105 and 106 year scale: Quater Pierce and G. M. Richmond. Hodge, E. T., 1925, Geology of Mt. Jefferson nary Research, v. 3, p. 39-55. R. L. Burk, Don Chase, C. E. Nash, L. A. (Oregon): Mazama, ann. ser., v. 7, no. 2, p. Sharp, R. P., 1969, Semi-quantitative differentia Scott, and J. M. Stroh assisted in the field. 25-58. tion of glacial moraines near Convict Lake, Special thanks to Mary Pollock Scott. Field Jackson, M. L., 1969, Soil chemical analysis - Sierra Nevada, California: Jour. Geology, work was largely supported by grants from Advanced course: Madison, Wisconsin V. 77, p. 68 - 91. the Society of Sigma Xi, the Corporation Univ. Dept. Soil Sci., 894 p. [1973). Sharp, R. P., and Birman, J. H., 1963, Additions Fund of the Department of Geological Sci Kiver, E. P., 1974, Holocene glaciation in the to classical sequence of Pleistocene glacia Wallowa Mountains, Oregon, in Mahaney, tions, Sierra Nevada, California: Geol. Soc. ences at the University of Washington, and W. C., ed., Quaternary environments: Pro America Bull., v. 74, p. 1079-1086. the Penrose Bequest of the Geological Soci ceedings of a symposium: Geog. Mon. 5, p. Taylor, E. M., 1965, Part I: History of volcanic ety of America. 169-195. activity, in Recent volcanism between REFERENCES CITED Mazamas, 1938, Aerial photographic survey of Three-Fingered Jack and North Sister, Ore glaciers on Mt. Hood, Mt. Jefferson, and gon Cascade Range: Ore Bin, v. 27, p. Alexander, E. B., 1974, Extractable iron in rela the Three Sisters, Oregon: Research Comm. 121-147. tion to soil age on terraces along the T ruc Mazamas. --1968, Roadside geology, Santiam and kee River, Nevada: Soil Sci. Soc. America McBirney, A. R., 1968, Petrochemistry of the McKenzie Pass highways, Oregon, in Dole, Proc., v. 38, p. 121-124. Cascade andesitic volcanoes: Oregon Dept. H. M., ed., Andesire conference guidebook: Andrews, J. T., and Miller, G. H., 1972, Quater Geology and Mineral Industries Bull. 62, p. Oregon Dept. Geology and Mineral Indus nary history of northern Cumberland 101-107. tries Bull. 62, 107 p. Peninsula, Baffin Island, N.W.T., Canada: McBirney, A. R., Sutter, J. F., Naslund, H. R., Thayer, T. P., 1939, Geology of the Salem Hills Part IV: Maps of the present glaciation Sutton, K. G., and White, C. M., 1974, and North Sanriam River basin, Oregon: limits and lowest equilibrium line altitude Episodic volcanism in the central Oregon Oregon Dept. Geology and Mineral Indus for North and South Baffin Isl and: Arctic Cascade Range: Geology, v. 2, p. 585-589. tries Bull. 15, 40 p. and Alpine Research, v. 4, p. 45-59. Meier, M. F., and Post, A. S., 1962, Recent var Ugolini, F. C., and Bull, Colin, 1965, Soil devel Birkeland, P. W., 1967, Correlation of soils of iations in mass net budgets of glaciers in opment and glacial events in Antarctica: stratigraphic importance in western Nevada western North America: lnrernat. Assoc. Quatemaria, v. 7, p. 251-269. and California, and their relative rates of Sci . Hydrology Pub. 58, p. 63-77. Wahrhaftig, Clyde, and Cox, Allan, 1959, Rock profile development, in Morrison, R. B., Paterson, W.S.B., 1969, The physics of glaciers: glaciers in the Alaska Range: Geol. Soc. and,. Wright, H. E., Jr., eds., Quaternary New York, Pergamon Press, 250 p. America Bull., v. 70, p. 383-436. soils: lnternat. Assoc. Quaternary Research Porter, S. C., 1970, Quaternary glacial record in White, S. E., 1962, Late Pleistocene glacial se Cong., 7th Proc., v. 9, p. 71-91. Swat Kohistan, West Pakistan: Geol. Soc. quence for the west side of lztaccihuatl, --1974, Pedology, weathering, and geomor America Bull., v. 81, p. 1421-1446. Mexico: Geo!. Soc. America Bull., v. 73 , p. phological research: New York, Oxford --1975a, Weathering rinds as a relative-age 935-958. Univ. Press, 285 p. criterion: Application to subdivision of gla Williams, Howel, 1957, A geologic map of the Birman, J. H., 1964, Glacial geology across the cial deposits in the Cascade Range: Geol Bend quadrangle, Oregon, and a reconnais crest of the Sierra Nevada, California: Geol. ogy, V. 3, p. 101-104. sance geologic map of the central portion of Soc. America Spec. Paper 75, 80 p. --19756, Equilibrium-line altitudes of late the High Cascade Mrs.: Oregon Dept. Blackwelder, Eliot, 1931, Pleistocene glaciation Quaternary glaciers in the Southern Alps, Geology and Mineral Industries Map and in the Sierra Nevada and Basin Ranges: New Zealand: Quaternary Research, v. 5, Text. Geol. Soc. America Bull., v. 42, p. 865- p. 27-47. Yaalon, D. H., 1971, Soil-forming processes in 922. --1976, Pleistocene glaciation in the southern time and space, in Yaalon, D. H., ed., Carver, G. A., 1972, Glacial geology of the part of the North Cascade Range, Washing Paleopedology: Origin, nature, and dating Mountain Lakes Wilderness and adjacent ton: Geol. Soc. America Bull., v. 87, p. of paleosols: Jerusalem, Israel Univ. Press, parts of the Cascade Range, Oregon [Ph.D. 61-75. 350 p. dissert.): Seattle, Univ. Washington, 75 p. Porter, S. C., and Denton, G. H., 1967, Chronol Crandell, D. R., 1965, The glacial history of ogy of Neoglaciation in the North America western Washington and Oregon, in Cordillera: Am. Jour. Sci., v. 265, p. 171- MANUSCRIPT RECEIVED BY THE SO CIETY Wright, H. E., Jr., and Frey, D. G., eds., 210. NOVEMBER 7, 1975 The Quaternary of the United States: Rampton, Vern, 1971, Late Pleistocene glacia REVISED MANUSCRIPT RECEIVED APRIL 29, Princeton, N.J., Princeton Univ. Press, 822 tions of the Snag-Klutlan area, Yukon Ter 1976 p. ritory: Arctic, v. 24, p. 277-300. MANUSCRIPT ACCEPTED JUNE 8, 1976 Printed ,n U S A