Diamond Pond, Harney County, Oregon: Vegetation History and Water Table in the Eastern Oregon Desert

Great Basin Naturalist

Volume 47 Number 3 Article 7

7-31-1987

Diamond Pond, Harney County, Oregon: vegetation history and water table in the eastern Oregon desert

Peter Ernest Wigand Washington State University, Pullman, Washington

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Recommended Citation Wigand, Peter Ernest (1987) "Diamond Pond, Harney County, Oregon: vegetation history and water table in the eastern Oregon desert," Great Basin Naturalist: Vol. 47 : No. 3 , Article 7. Available at: https://scholarsarchive.byu.edu/gbn/vol47/iss3/7

This Article is brought to you for free and open access by the Western North American Naturalist Publications at BYU ScholarsArchive. It has been accepted for inclusion in Great Basin Naturalist by an authorized editor of BYU ScholarsArchive. For more information, please contact [email protected], [email protected]. DIAMOND POND, HARNEY COUNTY, OREGON VEGETATION HISTORY AND WATER TABLE IN THE EASTERN OREGON DESERT

Peter Ernest Wigand'

Abstract —Cores obtained in 1978 from Diamond Pond, Diamond Craters, Harney County, Oregon, as part of the Steens Mountain Prehistory Project, provide a record of vegetation change on the sagebrush/shadscale ecotone and of local and perhaps regional water tables. Pollen, macrofossils, sediments, and charcoal from these radiocarbon-dated cores were analyzed. Varying abundance ofjuniper, grass, sagebrush, and greasewood pollen, and of aquatic to littoral plant macrofossils reflects changing regional effective moisture and local water table since 6000 B. P. Eleven dates spanning 5200 radiocarbon years and four regionally correlated volcanic ashes establish the dating of seven periods of diflferent moisture regimes;

1. Greasewood and saltbush pollen dominance before 5400 B.P. indicates shadscale desert. Rapid accumulation of alternating silts and medium sands lacking aquatic plant macrofossils and pollen reflects periods of ephemeral ponds with water table 17 m below the present level and considerable erosion of maar slopes, 2. Increasing sagebrush pollen from 5400 to 4000 B. P. indicates sagebrush expansion into shadscale desert. Scirpus, Riimex, Ceratophyllum. and Polygonum pcrsicaria macrofossils and finely laminated clayey silts evidence perennial pond.

3. From 4000 to 2000 B.P. abundant juniper and grass pollen reflects extensive juniper grasslands (juniper seeds from trees growing nearby fell into the pond during this period). Rising charcoal values indicate greater importance of fire. Deepest late-Holocene pond ca 3700 B.P. corresponds with postulated intensive human occupation of northern Great Basin marsh and lake locales. 4. Between 2000 and 1400 B.P. increased sagebrush pollen mirrors reduced effective moisture and reexpanding sagebrush steppe. More abundant Scirpus and Rumcx macrofossils evidence shallow pond. 5. From 1400 to 900 B.P. more numerous grass pollen indicates returning greater effective moisture resulting in deeper water with abundant Potainogeton. 6. About 500 B.P. increased greasewood and saltbush pollen evidences drought. Ruppia seeds and pollen and the mollusk Musculium indicate shallow, brackish water. 7. Abundant juniper and grass pollen reflects moister conditions between 300 and 150 B. P. Numerous Ceratophyl- lum fruits indicate deeper, freshened water. Since the mid- 1800s man and changing climate have encouraged sagebrush reexpansion. Increased Scirpus macrofossils indicate shallower water.

Although topographic diversity creates the of Malheur and Harney lakes during the past variety of habitats found in the Great Basin, 160 years. volcanic eruptions, tectonic activity, and Diamond Pond in the Diamond Craters sharp variations in climate, lasting to 100 200 area of the southern Harney Basin, Oregon, is years, have affected the size and diversity of an ideal location to watch changing vegetation these habitats (Mehringer 1986, 1977). Cli- patterns for three reasons. First, Diamond matic change in the Great Basin, especially in Pond lies adjacent to and at the same elevation the north, is best reflected in its fluctuating as Diamond Swamp (Figs. 2, 3), and its water lakes and marshes (Mehringer 1986). level is controlled by groundwater discharge. Since early in 1826 when Antoine Sylvaille Second, varying abundance of aquatic and lit- and five other trappers entered the Harney toral plant macrofossils reflects the expansion Basin ofsouthern Oregon (Fig. 1) and reached and contraction of the fringe of littoral and the river later named for him—the Silvies emergent aquatic species that presently sur-

River (Rich etal. 1950)—the volumes of Mai- round Diamond Pond (Fig. 3). Finally, heur and Harney lakes have varied consider- changes in the shadscale, lower sagebrush, ably (Piper et al. 1939). Accounts from early and juniper communities that adjoin on por- trappers, descriptions by early settlers, and tionsofDiamond Craters (Fig. 2) are reflected records maintained by local, state, and federal in the detailed microfossil record of vegeta- agencies reveal dramatic changes in the levels tion change unparalleled in the northern

Department of Anthropology, Washington State Universit\ , Pullman, Washington 99102.

427 428 Great Basin Naturalist Vol. 47, No. 3

MOUNTAINS

S T I N K I N WATER

R I D a E

Fig. 1. The Harney Basin of southeastern Oregon Ues nortliwest of Steens Mountain. The 1,2.50-m (4, 100-ft) contour is 1.2 m below the higliest beach ridge of Phivial Lake Mallieur and 4.,3 m below the drainage divide in Malheur Gap to the south fork of the Malheur River (Piper et al. 19.39:18). July 1987 WiGAND: Diamond Pond 429

Fig. 2. Diamond Craters, Harney Count}', Oregon, with it.s major geological features and vegetation associations.

Great Basin. At Diamond Pond both pollen ber 1826, when Peter Skeene Ogden, chief and macrofossils provide sensitive proxy data trader of the Hudson's Bay Company, and 35 of climatic change in the Harney Basin. men descended the Silvies River and discov- ered two lakes separated by a "ridge of land about an acre in width." A freshwater lake Historical Lake Level.s (Lake Malheur) about 1 mi wide by 9 mi long Early accounts of the sizes of Harney and lay east of a salty lake (Harney Lake) about 5 Malheur lakes vary considerably, due in part mi wide bv 10 mi long (Davies et al. to the time of year when the valley was vis- 1961:19-22)' The "Sylivills River" (Silvies ited. The Hudson s Bay Company trappers River) and two other small streams fed the that explored and trapped the Snake River freshwater lake, while another small river (Sil- country usually passed through the Harney ver Creek) flowed into "Salt Lake." Basin either in early summer when seasonal On 7 June 1827 Ogden returned to the runoff was greatest or in late fall when lake Harney Basin and found the lakes much levels would be at their yearly low. higher than in the previous fall and had to The lakes were first described on 31 Octo- detour northward to avoid the flooded basins 430 Great Basin Naturalist Vol. 47, No. 3

•.«-*- •'^vv" X**S

Fig. 3. Diamond Pond viewed from the northwest with the westernmost dome of Diamond Craters hehind it (W. Bright photo, September 1978).

(Davies et al. 1961:125-127). On 18 and 19 On 7 July 1859 Captain Henry D. Wallen June 1829 he ascribed a length of 20 mi (33 reported "a large salt lake"—20 mi long by 9 km) and a width of 15 mi (25 km) to "Sylvailles mi wide. Wallen named it "Lake Harney" in Lake" and a similar size to "Salt Lake" (Harney honor of General Harney, who was comman-

Lake) (Williams et al. 1971:160). A narrow der of the military district of the Columbia ridge of land a few feet wide separated the (Clark 1932:lll-il2). Again these dimen- lakes. These dimensions are larger than the sions are much larger than the basin that con- basins that contain these lakes today. tains Lake Harney. Despite the exaggerated Ogden's successor, John Work, camped accovmts of Ogden and Wallen, Piper et al. next to "Sylvailles Lake" (Malheur Lake) on 2 (1939:22) suggest that prior to 1864 Malheur July 1831 and reported in his journal that the Lake may have been relatively small. lake "was unusually high" and very brackish Since then Malheur Lake has nearly dried at (Haines 1971:132). By 1833 maps of the area least three times and has reached to or slightly published by the London mapmaker, A. beyond the meander lines of the official 1875 Arrowsmith, showed a chain of three lakes land surveys just as many times. According to called the Youxpell Lakes (possibly Harney, various accounts, after three years of very low Mud, and Malheur). Subsecjuently, the lake rainfall and runoff Lake Malheur was almost to- that was mistakenly thought to drain into the tally dry in 1889, and again in the fall of 1917 it Malheur River was named Lake Malheur. was relatively small (Piper et al. 1939). July 1987 WiGAND; Diamond Pond 431

CAPACITY (CUBIC METERS)

1,000.000.000 2 .000.000.000 3.000.000 .000

Spillover level into Ihe Malheur R

40.000 60.000 80.000 WATER SURFACE AREA (HECTARES)

Fig. 4. Relationship of lake depth, .surface area, and volume in the Harne\' Basin. At 1,254 m (4, 1 14 ft) Malheur Lake would discharge into the south fork of Malheur River through Malheur Gap (Piper et al. 1939:18).

Desiccation beginning in 1921 culminated over 10 m (30 ft) deep (Braymen 1984). At the during the 1930s. In 1930 and 1931 no water 1984 rate of rise, with each meter increase in ran into Malheur Lake from the Silvies River water depth covering an additional 11,290 ha and very little from the Donner und Blitzen (27,890 ac), the lake would have reached the River. The lake began receding, and bv Sep- 1,250-m (4,103-ft) level bv June of 1985 and tember 1930 it covered onl>' 810 ha (2,000 ac) covered an area of about 81,000 ha (200,000

(Fig. 4), and a year later only 203 ha (500 ac). ac). However, drought conditions during the

In 1932 it still received no water from the first half of 1985 and again during the first six Silvies River, but renewed flow from the Don- months of 1986 and 1987 reversed this trend. ner und Blitzen filled it to the 1,247-m (4,092- Fluctuating lake levels meant displacement ft) level covering about 10, 120 ha (25,000 ac). and financial "boom or bust for farmers and Excepting thermal springs on the lakebed, ranchers (Braymen 1984, Ferguson and Fer- Harney Lake was dry during these three guson 1978:29-30, Crick 1983). Changing years. In 1934 both lakes were dry, and ranch- lake size and water chemistry dramatically ers and farmers cut hay on the exposed bed of affected both the extent of the marsh adjoin- Malheiu- Lake (Ferguson and Ferguson ing Malheur Lake and the flora and fauna

1978:17, 109). Again in 1966 through 1968 the within it (Piper et al. 1939:23). lakes were almost drv (Walker and Swanson 1968:L13). Study Area Large lakes characterized the late 1870s to The Landscape earlv 1880s and recurred between 1895 and 1905 (Piper et al. 1939). In 1921 the lakes rose Diamond Pond (SWl/4, Sec. 30, T28S, briefly before the extremely low levels of the R32E, Diamond Swamp Quadrangle, Ore-

1920s and the total desiccation of the mid- gon) is a 2-m-deep, 46-m-wide perennial pond

1930s. After 1935 the lakes refilled and (Figs. 2, 3). It fills 92-m-wide Malheur Maar, reached peak levels during the 1950s (Walker an explosion crater, to within 9 m of the rim. and Swanson 1968:L13). In early spring of The maar is located on the westernmost dome 1984 the basins filled to form a lake some of the 67-km" Diamond Craters Volcanic 60,700 ha (150,000 ac) in extent and, in places. Complex at 1,265-m elevation. To the south- 432 Great Basin Naturalist Vol. 47, No. 3 west the confluence of Kiger, McCoy, and ward for 30 km through a verdant marshland Swamp creeks and the Donner und Bhtzen from 0.5 to 5 km wide. North of Diamond River form a broad, marshy floodplain. Dia- Craters near Voltage it discharges into Lake mond Swamp. The steep, east-facing side of Malheur (Fig. 1). fault-blocked Jackass Mountain lies to the Climate west across the valley (Fig. 1). Northward stretches the Harney Basin with the broad The topography of Harney Basin is the ma- expanses of the Malheur Marshes; beyond lie jor factor influencing local climate. Elevation the rugged Strawberry Mountains. To the varies from 1,250 m on the valley floor to southeast is Steens Mountain (2,961 m) with between 1,370 and 2,740 m in the surround- its usually snow-covered crest 32-48 km from ing uplands. The Harney Basin receives most the craters. of its precipitation from winter and spring Diamond Craters, first described by I. C. storms derived from the marine air that flows Russell (1903:54-57), is situated near the into the Pacific Northwest (Fig. 5). Weather southern end of the Harney Basin, a 13,727- Bureau records collected since the late 1800s km" area of large-scale, post-Miocene subsi- indicate that the Harney Basin as a whole is dence into underlying magma chambers semiarid, but the Blue Mountains to the north (Walker 1979:5-6). The craters consist of six and Steens Mountain to the south can receive major and one minor structural domes that up to three times the average regional precipi- range in height from 50 to 120 m and comprise tation. Snow, which accounts for about one- an area over 9 km in diameter, which exhibits third of the annual precipitation, may fall on a variety of volcanic features (Peterson and the valley floor between October and June Groh 1964, Brown 1980:12). and on the mountains in any month. The aver- Surface drainage from the surrounding up- age annual total varies from 115 cm (45 in) at lands collects in the north central part of the Burns to 64 cm (25 in) at the Harney Branch Harney Basin in two large, marsh-surrounded Experiment Station and 84 cm (33 in) at Dia- lakes periodically joined at the Narrows (Fig. mond.

1). At its greatest extent in May and June, Daily and seasonal temperature range is Malheur Lake typically extends 26-29 km wide, relative humidity is low, evaporation is eastward from the Narrows and is about 13 km great (about 4.8 times the annual rainfall; across and up to 3 m deep (Waring 1909:11). Piper et al. 1939), and the number of cloudless When the water level in Malheur Lake ex- days per year averages about 120. The grow- ceeds 1,247.1 m (4,091.5 ft), it spills through ing season varies from 80 days at the Harney the Narrows into Mud Lake. At 1,247.7 m Branch Experiment Station to 117 days at

(4,093.5 ft), Mud Lake overflows westward at Burns. Although during the last 80 years an- Sand Gap into 11-13-km-wide Harney Lake nual mean temperature below 1,280 m (4,200

(Piper et al. 1939:20-21). Although Harney ft) in Harney Basin has averaged about 7.8 C Lake's depth may change up to a meter or (46 F), differences result from the peculiari- more annually, its area is less variable because ties of local circulation. At Burns (1,267 m)

it lies in a steep-sided basin. over a 76-year period the mean January tem- Silver Creek supplies Harney Lake from perature was -3.8 C (25.1 F), and the mean the northwest, whereas Malheur Lake re- July temperature was 19.8 C (67.6 F). The — ceives runoff from the north through the Sil- extremes ranged between —36 and 39 C ( 32 vies River and Poison Creek (Piper et al. 1939; and 103 F). Strong prevailing winds come Hubbard 1975). To the south the Donner und from the southwest throughout the year, but Blitzen River and its tributaries originate on especially during March through June (Mar- Steens Mountain where, during uplift and tin and Corbin 1931, Sternes 1960, U.S. De-

later Pleistocene glaciation, it eroded deep partment of Commerce, Weather Bureau canyons in the gentlv dipping basalts (Russell 1954-1984). 1903:17, 1905:84-85, Smith 1924, Fuller Lake levels in the Harney Basin depend 1931:38, Hansen 1956:14, Bentlev 1970:21, primarily upon the discharge of its four major 67, 1974:213, 217, Mehringer 1985a:Fig. 12). streams (Fig. 6) and groundwater recharge Between Frenchglen and Diamond Craters (Russell 1903:29); however, they also mirror the Donner und Blitzen River flows north- total precipitation. Precipitation amounts in July 1987 WiGAND: Diamond Pond 433

HARNEY BASIN CATLOW ALVORD VALLEY VALLEY

1980s

1970s IkJ ^-*"-——*- 4i

1960s

Mameur Buena Vlata a Alvord Refuge • Rancti

1950s Juniper ^ Lake 1940s bJuihlikLi^Jj Am Ul P Ranch

1930s

Squaw Butle Voltage Hart Mtn Sunrfse Refuge Valley

1920s

Harney Branch Experiment Station

1910s ku-J

Blltzen Juniper Andrews Ranch

1900s lU

1890s ^

1880s

RAINFALL 1870s ( CM )

J tjl W J 3 N A A A U E O N R Y L P V 1860s AHU C V EMT E lU R MB Camp Warner Camp Harney Y BE E R

Fig. 5. Decadal means (e.g., 1971-1980) for monthly rainfall in the Harney Ba.sin .since the 1860s. Monthly averages for the 76-year Burns, Oregon, rainfall record are illustrated in the figure key (bottom center). .

434 Great Basin Naturalist Vol. 47, No. 3

SILVER CREEK/

"^ ' ' I \ '

1 900 1920 1940 19 60 1980

YEAR A . D

Fig. 6. Stream discharge records, expressed as percent of the mean tor all years of record for major streams of the Harney Basin.

the Harney Basin and the Catlow Valley to the tween 20 and 30 cm (8 and 12 in) a year in the south show similar trends during the last 80 Harney Basin. Recording stations along the

years (Fig. 7). Annual rainfall averages be- western edge ofthe basin average about 30 cm July 1987 WiGAND: Diamond Pond 435

Paulina

Burns

Camp Harney

Voltage /Malheur Refuge Headquarters

Harney Branch Experiment Station

5.. 50 Frenchglen

-L

Diamond

Camp ^ Warner B li t z e n

I \ \ \ 1860 1880 1900 1920 1940 1960 1980

YEAR A . D .

Fig. 7. Rainfall in the Harne\' Basin and the Catlow Valley expressed as a percentage of long-term means. The northernmost stations are at the top.

(12 in) annually, whereas stations located in and moisture), site (slope, aspect, and eleva- the north central part of the basin average tion), and temperature. On the surrounding closer to 20 cm (8 in) annually. mountains plant species from the Rocky Mountains, the Cascades, the Sierras, and the Vegetation mountain ranges of the Great Basin combine The terrestrial flora of the Harney Basin with endemic species to form characteristic reflects the environmental restrictions of a dry plant comiuunities (Price 1978). climate and thin, volcanic, often saline soils. A transect between Diamond Craters and Distribution of local plant communities varies the top of Steens Mountain cuts across at least according to characteristics of soil (depth, pH, six distinct vegetation zones that have been 436 Great Basin Naturalist Vol. 47, No. 3

ft,«^> *.;^*~**

"^^V • ^

Fig. 8. View northward toward the lava flows northeast of Diamond Craters. The area between Northeast Dome and White Lake (upper right) has the densest stands ofjuniper on Diamond Craters (P. Wigand photo, June 1980).

studied and variously named during the past Dome (Figs. 2, 3). The Lower Sagebrush 30 years (Hansen 1956, Faegri 1966, Urban Zone covers most of Diamond Craters and 1973, Mairs 1977). Generally, these zones supports, in addition to the dominant shrubs, from lowest to highest are: (1) the Shadscale a variety of grasses, including Stipa comata Zone dominated by Sarcobatus vermiculatus (needle-and-thread grass), Stipa thurheriana (black greasewood), Atriplex spinosa (spiny (Thurber's needle-and-thread grass), and hopsage), and Atriplex confertifolia (spiny Bromiis tectorum (cheatgrass). The Juniper saltbush); (2) the Lower Sagebrush Zone dom- Zone covers the low-lying lava flows north of inated hy Artemisia tridentata var. tridentata North Dome (Figs. 2, 8). Big sagebrush, (big sagebrush) but with abundant Holodiscus dumosus var. glabrescens (gland Chrysothomnus nauseosus (gray rabbit- ocean-spray), Ribes cereum (squaw currant), brush), C. viscidiflorus (green rabbitbrush), Ribes aureiim (golden currant), rabbitbrush, Tetradymia glabrata (littleleaf horsebrush), ferns (in moist crevices in the lava flows), and and T. canescens (gray horsebrush); (3) the native bunchgrasses, primarily Agropyron Juniper Zone characterized hy J uniperus occi- spicatum (bluebunch wheatgrass), grow dentalis; (4) the Aspen Zone with both Pop- among junipers that, according to counts of ulus tremidoides (quaking aspen) and Cerco- tree rings collected by personnel of the Bu- carpus ledifoliiis (mountain mahogany); (5) reau of Land Management (BLM), are up to the Upper Sagebrush Zone dominated by 200 years old.

Artemisia tridentata var. vaseyami; and (6) Diamond Pond lies within the ecotone be- the Subalpine Grassland (Mehringer and tween shadscale and lower sagebrush commu-

Wigand 1987:Fig. 4). Of these, the Shadscale, nities on Diamond Craters. The terrain east Lower Sagebrush, and Juniper zones occur at and south of Malheur Maar is dominated by Diamond Craters. big sagebrush and its associates. North and The Shadscale Zone occupies thin, stony west of the maar black greasewood and spiny soils on the south and west sides of West hopsage intermingle with big sagebrush, July 1987 WicAND: Diamond Pond 437 littleleal horsebrush, Tetradipiiia spinusa In the moist ground at the water's edge and (spiny horsebrush), and some Artemisia in the shallow water of the pond's margins spinescens (bud sage). Growing among the grow Bumex umrititmts (golden dock). Ranun- shrubs are Leptodactylon piin<:,cn.s (prickly culus cynibalaria {shore buttercup), Veronica phlox), Chaenactis duu^lasii var. acJiilleaefo- anagallis-aquatica (water speedwell), and Ua (dusty maiden), and tidytips {Laijia ^landii- Juncus balticus (Baltic rush). Typha latifolia losa). (common cattail) lining the northern and

Within Malheur Maar aspect determines western margin of the pond is broken by a whether shadscale or big sagebrush commu- stand ofPhragmites communis (common reed) nities predominate. Whereas the south-facing on the northeast shore. Along the north shore slope supports spiny saltbush, some spiny the cattails are enclosed by a stand of Scirpus hopsage, and an occasional big sagebrush or acutus (hardstem bulrush) that dominates the green rabbitbrush, the east- and north-facing southern, western, and northern shores of Di- slopes are covered by green rabbitbrush and amond Pond. Thick growths of Ceratophyl- big sagebrush interspersed with hopsage and lum demersum (hornwort) and Potamogeton occasional spiny saltbush. The west-facing pectinatus (sego pondweed) clog the pond. slope consists of a talus with a few big sagebrush and bunches of giant wildrye (Ehjmiis Methods cineiTus). A single golden currant survives in

cliflF the shade offered by the on the north- In June 1978 a crew that included Dr. P. J. facing slope of the maar. Mehringer, Jr., K. L. Petersen, myself, and Between the shrubs of the south-facing members of the Steens Mountain Prehistory slope are Amsinckia tesseJlata (tessellate Project summer field school began coring fiddleneck), Cnjptontha circumscissa (matted near the center of Diamond Pond. Dr. cryptantha), C njptantha torretjana (Torrey's Mehringer and students from the Depart- cryptantha), and Astragalus lentiginosus ment of Anthropology's fall 1978 palynology (freckled milkvetch). A dense blanket oi Dis- class completed coring in late October of the tichlis striata (alkali saltgrass) and bunches of same year (Fig. 9). We obtained 14.97 m of bora.\ weed {Nitrophila occidentalis), saltwort core with a modified Livingston piston corer

{Glaux maritiina ), and poverty weed {Iva axil- (Gushing and Wright 1965) that was operated laris) thrive on the lower slope close to the from a drive tower anchored to a wood and water s edge. styrofoam raft. Overlapping cores were Bromus tcctorum (cheatgrass) occurs collected for the top 5.45 m. After collecting throughout the maar. Onjzopsis Jiymenuides each core in 3-m-long, 10-cm-diameter bar- (Indian ricegrass) and Sitanion hystrix (bottle- rels, we cut them to the actual length of sedi- brush s(iuirreltail grass) are locally abundant ment recovered, capped them, and returned along the northwest rim of the maar, and tufts them to cold storage at Washington State of Muhlenbcrgia asperifolia (alkali muhlen- University. bergia) and pockets of the exotic grasses, Bro- Prior to description and sampling, we ex- mus japonicus (Japanese bromus) and posed the sediments by cutting the barrels Afiro}}yron cristatum (crested wheatgrass), lengthwise with a rotary saw, thereby avoid- occur sporadically on the slopes of the maar. ing distortion of sediments by extrusion. Growing close to the western and north- Gores were correlated by distinctive strati- western margins of the pond are stands of graphic markers, especially volcanic ashes, European and native weeds. Urtica dioica and by depth. Generally, our sediment de- ssp. gracilis var. angustifolia (stinging nettle) scription adhered to Soil Survey Manual (Soil and Lcpidium latifolium (pepperwort) pre- Survey Staff 1951) except that boundary dis- dominate, with some Cirsium arvense (Cana- tinctness followed Mehringer and Sheppard dian thistle), Epilohium minutum (willow- (1978). We determined color (moist and dry) herb). Aster frondosus (short-rayed aster), with the Munsell Soil Golor Ghart (1975). Solidago occidentalis (western goldenrod), Sediments with recurrent series of texture and in open, sunny areas Potentilla anserina differences are denoted as laminae, whereas (common silvei-weed) and Chenopodium al- sequences of similar texture but different bum (pigweed). color are denoted as bands. 438 Great Basin Naturalist Vol. 47, No. 3

Fig. 9. WSU Department of Anthropology palynology class coring Diamond Pond (October 1978). View is to the southeast. Far slopes are dominated by sagebrush. Hardstem bulrush {Scirpus acutiis) and cattail (Typha latifolia) are visible in the foreground.

Before sampling the cores for micro- and 10, 850 ±200 Lifcopodium spores (batch no. macrofossils, we removed 11 radiocarbon and 006720) (Stockmarr 1971, 1973), and weak 4 tephra samples to establish a regional se- HCl to all but 24 samples as the first extraction quence of dated volcanic ashes (Mehringer et procedure. The 24 samples, from near the top al., in preparation). Microfossil sampling in- of the sequence, were extracted as part of a terval was determined by depth, sediment pollen class project in fall of 1978. Ten tablets, type, boundary location, and apparent age. each containing 12,500 ±500 Lycopodiwn Several replicate samples were collected from spores (batch no. 212761), were added to each each of 312 levels by removing a 1 x 1 x 2-cm of these samples. block (2 cm ) with a wire frame cutting device Using 400X magnification, I counted 96

(Kolva 1975:Fig. 6), or, in a few cases where samples from Diamond Pond with a range of this was not possible, sediments were packed 406-2,937 terrestrial pollen (mean 949 ±543) into a round-bottomed scoop with a volume of and 104-3,281 Lijcopodiiim tracers (mean 2. 3 cm^ (Fletcher and Clapham 1974, Barthol- 612 ±456) (Fig. 10). With the addition of omew 1982:15). We used one replicate sam- aquatic pollen tvpes and spores, counts range ple from each level for microfossil analysis and from 436 to 3,359 (mean 1,135 ±577). When another to determine dry weight and organic the algae are added, the number of micro- and carbonate carbon percentages by weight fossils per sample ranges from 471 to 4,400 loss on ignition at 600 and 950 C (Dean 1974). (mean ca 2,000). In a few cases the algae were Pollen extraction generally followed so abundant that their numbers had to be Mehringer (1967:137); after acetolysis the approximated from the number of algae ob- samples were mounted in silicone oil (2000cs). served while counting at least 200 Ly- To estimate the number of microfossils per copodium tracers. In addition, two sizes of volume of sediment, we added 10 commer- charcoal. Charcoal A (25-50 microns) and cially prepared tablets, each containing Charcoal B (> 50 microns), were counted. July 1987 WiGAND: Diamond Pond 439

DIAMOND POND

Lycopodium Terrestrial Pollen Terrestrial Pollen cm' Counted Counted (with 95% confidence intervals) 100,000 200,000 300,000 400,000 1000 ^^1000 2000 3000 440 Great Basin Naturalist Vol. 47, No. 3

procedure for comparison of the microfossil Oat* A Radiocarbon data for all Steens Mountain Project pollen

S a m p I • • counts. All pollen and charcoal ratios pre- sented were smoothed using a three-level weighted average, (a+2b-^c)/4 (Holloway 1958). ZONE 3

Results

T a p hr a Dating and Deposition Rate Eleven radiocarbon determinations and four regionally correlated tephras from Dia- mond Pond cores establish a chronology spanning the last 5500 years B.P. and provide a — basis for the deposition rate curve (Fig. 11). LU 6.0 2 Except between ca 4500 and 1500 B.P. when deposition slowed, sediment has accumulated rapidly .since 6200 B.P. Modern Ceratophijllum demersum from Diamond Pond dating 126 ±1.6% modern X 8.0 (VVSU-2529) agrees with postbomb modern

samples of the last six years or so (Baker et al. 1985). This indicates that groundwater sup- plying Diamond Pond today does not contain old carbonates that might result in erroneous radiocarbon dates.

Sediments

Diamond Pond deposits above 11.4 m (ca 5450 B.P.) primarily consist of dark, laminated, fine silty clay rich in organic detritus and well-preserved macrofossils (primarily seeds and snail shells). Laminated inorganic clays, silts, and sands with occasional lenses of sandy fine gravel containing angular and spherical clay clasts characterize sediments RADIOCARBON AGE BP below 11.4 m.

Fig. 11. Pollen samples with respect to depth, radio- Grain size analyses of 33 sediment samples carbon age B. P. , and pollen zones. from Diamond Pond indicate occasional increases in sand content resulting in a much

micro- and macrofossils, I subdivided the dia- coarser median and mean grain size, poorer grams into zones by using a cluster analysis sorting, and more positive skewness (Fig. 12). program that joined only neighboring samples Above 11.4 m sediments with finer mean and or adjacent groups into a dendrograph (Orloci median grain size reflecting increased silt and 1967, Petersen 1981:45-46). clay content are typical. Characteristically, Both to summarize and illustrate major these sediments are less positively skewed, changes in the micro- and macrofossil records, better sorted, and more leptokurtic than

I plotted ratios of specific plant species by those below 11.4 m. However, at least three radiocarbon age. Ratios selected for Diamond units of coarser sediment interrupt these finer Pond and other Steens Mountain lakes use the deposits. most abundant pollen types, usually from Organic and Carbonate Content plants that characterize the vegetation zones of the Harney Basin and Steens Mountain. Plots of weight loss on ignition of 312 sam- These ratios were calculated as a standard ples (Fig. 13) show a gradual increase in or- July 1987 WiCAND: Diamond Pond 441

2 3 2 40 SO 80 94 20 40 60

Fig. 12. Sediment parameter.s and proportions ot gravel, sand, silt, and clay.

DIAMOND POND WEIGHT LOSS AT WEIGHT (GRAMS CM"') WEIGHT LOSS AT 600°C (%) SSCC (%)

0.0 I 20 2 34 20 40 60 5 10

Fig. 13. Weight loss on ignition (first a.\is), and organic carbon (second axis) and carbonate (third axis) percentages from 312 samples from Diamond Pond. Note that organic carbon weight on the first axis is the difference between weight loss at 950 C and weight loss at 600 C. 442 Great Basin Naturalist Vol. 47, No. 3

«' 'j" 0^ <;* ^^ ']' (1°

! I t : . r'."V"r''"V'."r

, • \-\-H i-ri I" [ \

m :ii;..

t *

ill ^^ 1 I

Fig. 14. Relative percentage diagram of all microfo.ssils plotted by depth. ganic matter from about 6200 B.P. to the which are abundant and classed separately) present. Organic carbon percent remain.s low are assigned to either monolete or trilete below 11.4 m (ca 5450 B.P.) when the first spore categories as a percent of total pollen. A significant increase occurs. Organic carbon large number of monolete spores compare fa- percent reached its maximum within the past voral)ly with Cystopteris fragilis (bladder- 300 years. fern). Most trilete spores were Pteridium Carbonate percentages are less than 2% be- aquilinum-type (bracken fern), although a low 11.4 m. Above 11.4m they generally vary fewPiluIaria amehcana (pillwort) spores were between 1 and 6%. Increases in carbonate identified. content may reflect major variations in water Algae, including Rotryococcus, Tetrae- table or water chemistry that reflect signifi- dron, five species oi Pediastrum, and two un- cant climatic change. known types of algae are plotted in the main diagram as percent of total pollen. Following Microfossils the procedure adopted for the Steens Moun-

Sixty-six pollen types, of which 11 were tain Project, I divided charcoal into two cate- from aquatic or emergent aquatic plants, were gories, one of 25-50 microns and another of >

identified (Fig. 14). Although included in the 50 microns and plotted it as a percent of total terrestrial pollen sum, 3 other pollen types, pollen. Rumex, Ranunculus, and Umbelliferae, be- Pollen ZONES.—Three pollen zones, based long to genera with species that grow in water upon the eight most common terrestrial plant or poorly drained habitats. All terrestrial pol- pollen types (Pinus, Juniperus, Aiiemisia, len types appear as a percent of total terres- Gramineae, Sarcohatus, other Chenopodi- trial pollen (pollen sum), whereas aquatic pol- ineae, Tubuliflorae, and Umbelliferae), are len types are expressed as a percent of the apparent in the dendrograph (Fig. 15). To total of both terrestrial and aquatic pollen (to- eliminate the influence of aquatic and littoral tal pollen). plants on formation of the zones, they are All spores (except Equisctum and Isoetes, excluded. In addition, the two lowest pollen July 1987 WiCAND; Diamond Pond 443

///^ f '' "^ ^ ^ / ~'^ ^'

^°

% POLLEN SU^ *POLLEN TOTAL

Fig. 14 continued. samples, 12.9 m (ca 5800 B.P.) and 14.0 m (ca Macrofossils 6000 B.P.), were omitted from the sample set used for zoning beeause they contained pollen I recovered macrofossils of 16 plant genera, grains probably derived from Pliocene and along with five species of mollusks and two Miocene deposits. Although other zone divi- species of ostracods, from Diamond Pond sions are possible, the breaks at 7.25 and 5. 15 (Fig. 17). Plant macrofossils include the well- m (ca 3630 and 1750 B.P.) are the most obvi- preserved seeds and occasional fruits of ter- ous and useful (Figs. 15, 11). restrial, aquatic, and littoral species. Pollen accumulation rates. —From the Shells of the mollusks Lymnaeo palustris, average years per centimeter for each zone Planorbella subcrenata, Gyraidus parvus, and estimates of the total microfossils per sam- Gyrauhts crista, and Musculiiim securis occur ple, 1 calculated the number of microfossils primarily in Zones 1 and 3 but were not found deposited per square centimeter per year for in the present aquatic vegetation (Fig. 17). each sample. Pollen accumulation rates for Living Lymnaca pahistris were found in Cer- Zone 1 between 11.9 and 8. 1 m and in Zone 3 atophyUum dcmcrsum collected from Dia- between 3.8 and 0.85 m are from 3 to 10 times mond Pond but were not recovered from larger than the average for Zone 2 (Fig. 16). within the sediments. More pollen is accumulating in the sediment The topmost macrofossil sample yielded a than can be accounted for given the time rep- fish scale. Its ctenoid shape indicates that it resented in Zones 1 and 3. Pollen accumula- came from a fish related to the sunfishes. The tion rates for Zone 2 average about 10,000 recently introduced largemouth bass has this pollen grains per cm^ per year, rather than the type scale. In addition, 22 two- to three- 33, 140 pollen grains per cm per year estimated millimeter-long, lunate-shaped objects, each for Zones 1 and 3. Rapid pollen accumulation in with a hard enamel coating (perhaps teeth), Zones 1 and 3 corresponds with major increases were recovered from 9. 1 to 8.7, 7.8 to 7.7, 4.0 in Sorcobatus pollen percentages and of sand in to 3.8 m, and in particular from a unit with the sediments of Diamond Pond. crumb structure from 6.9 to 6.6 m. 444 Great Basin Naturalist Vol. 47, No. 3 DIAMOND POND ZONES

I ...... 1-1,950

1,000

CO A.D. < B.C. LjJ < -1,000 z: LlI <_J

-2,000

-3,000

-4,000

Fig. 15. Zoning diagram showing tlie clustering oi adjacent pollen samples plotted by age.

Although numbers of plant macrofossils and In general, variation in plant macrofossil mollusk shells vary dramatically from sample abundance suggests that submerged aquatic to sample, patterns of association and major plants, emergent aquatic plants, and littoral trends are evident. Below 11.8 m (ca 5500 plants respond as groups (Table 1). It appears B.P.) plant macrofossils are absent; instead, that although changes in the numbers of sub- some beds contain numerous aquatic insect merged aquatic plant macrofossils may be out parts. Especially abundant were members of the of phase with variations in the abundance of family Corixidae (water boatman), which feed on emergent aquatic plants, the species within algae and other minute aquatic organisms. each group fluctuate in concert. July 1987 WiGAND Diamond Pond 445

to POLLEN / CM sponds zone boundaries. Whereas percent- 16,000 ages o( Piniis (pine), sagebrush, Cyperaceae, and other Potomop,cton pollen have increased since 6200 B.P., pollen values of greasewood have declined. Ratios of pine, sagebrush, and greasewood emphasize these trends (Figs. 20,

21). The second long-term pattern is characterized by a pronounced increase in pollen values between about 3800 and 2000 B.P. Pollen percentages of other Chenopodiineae

(although it also shows a general decline in pollen values since 6200 B.P.), grass, and juniper were all significantlv larger at that time (Figs. 14, 20, 21). Charcoal abundance with respect to pollen sum also increases between 3800 and 2000 B.P. (Fig. 22). According to the Pearson product-moment correlation coefficient, both

sizes of charcoal are positivelv correlated (r = 0.84069, significant at P = .0001). Additional ratios of Charcoal A, Charcoal B, and total charcoal to each of the major types of pollen repeat the same pattern of charcoal abundance. These long-term microfossil trends help

characterize the pollen zones. Zone 1 is characterized by overwhelming abundance of

Fig. 16. Terrestrial pollen cm "/yr ' plotted by radio- greasewood pollen. Increasing percentages of carbon age. Depo.sition rates were determined from the sagebrush and relatively high percentages of first derivative of a fourth order polynomial fit of radio- juniper and grass and non-Sarcobatus carbon ages with depth (Fig. 11). Chenopodiineae pollen—probably Atriplex (saltbush)—are the hallmarks of Zone 2. In Occasionally, both the seeds and pollen of Zone 3 sagebrush pollen reaches its maximum certain plants occurred in Diamond Pond. To abundance, whereas grass and juniper pollen compare fluctuations in the abundance of the percentages decline. macrofossils of these species with changes in Short-term deviations of 100 or 200 years' their corresponding pollen types, standard- duration interrupt the general trends outlined ized macrofossil counts and pollen percent- above (Fig. 13). Usually these variations are ages as a percent of total pollen minus the six minor, but occasionally significant change in most abundant pollen types {Arte7nisia, Sar- pollen contribution is evident. In general, in- cobatus, Juniperus, Gramineae, Pinus, and creases in greasewood pollen percentages are other Chenopodiineae) were plotted (Figs. out of phase with sagebrush, grass, and ju- 18, 19). niper pollen percentages. Although grass and juniper pollen values usually vary in the same Discussion direction, in Zone 3 they are often out of phase. Greater pine pollen percentages gen- Interpretation of the Pollen and Seed Record erally correspond with or immediately follow increases of juniper pollen percent. (Pollen, Macrofossils, and Ratios) Generally, the numbers of submerged, Both long- and shori;-term trends in the emergent, and littoral macrofossils generally pollen and macrofossil records are evident have declined since about 5500 B. P. (Fig. 23). (Figs. 14, 17). Long-term trends are charac- Dramatic fluctuations in their numbers do not terized by two patterns, one that crosscuts necessarily correspond to changes in the ratio zone boundaries and another that corre- of aquatic (submerged plus emergent) to lit- 446 Great Basin Naturalist Vol. 47, No. 3

10 10 10 100 10 10 tOOO

F^C=

)-"

Fig. 17. Numbers of macrofossils recovered from Diamond Pond, standardized for 1,000 ml of sediment, are plotted on a log scale.

toral macrofossils. The ratios of both aquatic grass and juniper pollen percentages between (Potamogeton pectinatus, other Potamogeton, 4000 and 2000 B.P., values of the major ter- Polygonum persicaria, and Mijriophijllum) to restrial pollen types at Diamond Pond have littoral (Cyperaceae, Ttjpha, and Rumex) always been similar to those obtained from plant pollen and aquatic to littoral plant greasewood communities in the Albion Range macrofossils reveal dramatic short-term fluc- (Davis 1984) and from the Terreton Basin of tuations in the abundance of aquatic and lit- southeastern Idaho (Bright and Davis 1982). toral plants (Figs. 21, 23). Grass and juniper pollen percentages from Modern pollen rain. —The surface pollen 3800 to 2100 B.P. and 1100 to 900 B.P. are studies of Davis (1981:Appendix 16, 1984: comparable to those obtained from Davis's Fig. 3) and Henry (1984) in southern Idaho juniper and grassland communities, but the offer modern pollen comparisons for the fossil shadscale community pollen component is pollen record from Diamond Pond. Although much stronger.

Davis's Albion Mountain surface pollen per- Comparison of modern and fossil pollen val- centages do not "duplicate" environments of ues suggests that plant communities that grew deposition in lakes and ponds, they provide around Diamond Pond when juniper and several useful clues that help characterize past grass pollen were most abundant have no plant communities at Diamond Craters. modern analogue either in the Albion Range These are: or at Diamond Pond. Fossil pollen evidence 1. Juniperus pollen in excess of 7% indicates that juniper from Diamond Pond indicates that juniper was growing near or at the site. and grass were part of the nearby shadscale 2. Sarcobatus pollen in excess of 10% characterizes community or that grass and juniper grew greasewood communities. 3. Artemisia values in excess of 50% characterize big very close to greasewood- and saltbush- sagebrush communities. dominated areas. Juniper values of 8 to 12%, 4. Other Chenopodiineae values in excess of 20% charac- as well as radiocarbon-dated juniper from terize shadscale communities. woodrat middens at Diamond Craters, indi-

Because Diamond Pond is located in the cate that juniper was growing in areas where it ecotone between the shadscale and lower does not grow today (Mehringer and Wigand sagebrush zones, aspects of both communities 1987, 1988). However, because the values of influence the pollen assemblage. Except for juniper pollen are on the low side of those July 1987 WiGAND; Diamond Pond 447 —

448 Great Basin Natur.\list Vol. 47, No. 3 I

.6* ..v^'^ .'°^" ft* ol-*' .o^^*' oN^*" .V^ SP>^ .^r^' .x^^^ ...'•':>••• ...-'„.,.'•'• A\^'' .11*'> ..' „.^-'>" '••;.'"' ,...'"'„..>'" ^i p..'* ,,.•"•' ,.•••

20 40 10 20 10 20 10 100 20 40 60 80 10 100 lOOO 20 40 10 100 1000

12 0-

Fig. 18. A comparison ofpollen percentages (percent of total pollen exclnding the six most abundant terrestrial pollen types Artemisia. Gramineae, Sarcobatus, Pimisjuiiipenis. and other Chenopodiineae) and numbers of macrofossils (standardized to 1,000 ml of sediment; Fig. 17). with increased runoff, and higher lake levels table fluctuations (reflected by rapid changes and expanded marshes characterize wet in the dominance of one group or the other decades. This pattern has been aptly demon- that may or may not reverse the general trend strated during the last 10 years in the Harney from submerged acjuatic to littoral species). If Basin. plant macrofossils were uniformly abundant

It is evident that juniper spread several throughout the deposits of Diamond Pond, a times during the past 4000 years into areas simple ratio of aquatic to littoral species where it does not grow today (Mehringer and should clearly reveal these variations. Deeper Wigand 1987, 1988). If this'was the result of water would be reflected in greater abun- increased precipitation, evidence for result- dance of submerged and emergent aquatic ing higher water tables should be reflected in plant macrofossils at the expense of those from the water depth fluctuations indicated by the littoral species. However, the numbers of plant macrofossil record from Diamond Pond. plant macrofossils vary greatly (Fig. 23). Higher water tables should correspond with The number of seeds or fruits deposited in increased juniper pollen values. pond sediments is dependent upon the num- Macrofossils and water table. —At Dia- ber of seeds produced by the plant, how close mond Pond variation in assemblages of plant it is to the place where the seeds are de- macrofossils can evidence changes in water posited, the plant's height, and whether or

depth resulting from (1) gradual or rapid infill- not its seeds can float (Birks and Mathewes ing of the pond (reflected by the general suc- 1978). Before 5500 B.P. absence of seeds in cession from submerged to emergent aquatic the sediments of the maar indicates that there

plants to littoral plants), or (2) periodic water was no vegetation growing in the pond. Since July 1987 WiGAND; Diamond Pond 449

„vv*"

.6^

,«'" ul-

50" ZONE

20 10 100 10 5 ip 20 40 10 100 1000 20 Ip 100 10 00 60 80 00 p 20 [0

Fig. 18 continued.

the establishment of Diamond Pond, how- the center of the pond and reduced the area in ever, an uninterrupted pollen record indi- which acjuatic plants could grow. cates that it never dried out. Reduced num- Because at least 15 m of sediment has accu- bers of macrofossils after 5500 B.P. could mulated in Diamond Pond during the past mean either that water depth in the pond had 6000 years, the geomorphology of the maar become so great that both aquatic and littoral probably has changed radically. The expected plants had retreated to the margins of the proportion of aquatic to littoral plants in a

maar and away from the center (the coring broad, shallow basin as Diamond Pond is to- site), or that the species that were dominant day would have been quite different in the could not disperse their seeds as well. Abundant steep-sided, funnel-shaped maar of the past. plant macrofossils could mean the reverse. Because the diameter of the pond was As water depth increased, one would ex- smaller then, the center of the pond would pect the number of seeds to decrease. How- always have been closer to all the plant com- ever, the number of aquatic macrofossils munities in the maar even when water depth would increase in proportion to littoral macro- was great. Therefore, even though the gen- fossils not only because aquatic plants were eral scenario described above would hold, the closer to the center of the pond than littoral number of seeds would have been relatively species, but also because there was more area much greater. Likens and Davis (1975) call

for aquatic plant growth. As the water table this phenomenon focusing . As the pond dropped, one would expect greater macrofos- filled and became relatively much broader, sil abundance and the proportion of littoral one would expect the total number of macro-

species should increase as they approached fossils to decrease. This is what we observe 450 Great Basin Naturalist Vol. 47, No. 3 Ceratophylluiu demersum fruits and leaf hairs

CaratophyL Caratophyl. fruits leaf hairs

Number of Fruits or Leaf Hairs

500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 Radiocarbon Age B.P.

Fig. 19. A comparison of the number oi Ceratophyllum demersum leaf hairs (expressed as percentage of the pollen sum) and the number o( Ceratophyllum demersum seeds (standardized to 1,000 ml of sediment; Fig. 17).

Fig. 20. Smoothed (a+2b + c)/4 ratios of major pollen types, Part A. July 1987 WiGAND; Diamond Pond 451

1000

2000

30O0

4000

5000

6000

Fig. 21. Smoothed (a + 2b + c)/4 ratios of major pollen types. Part B.

Zone

1000 II

2000

3000

4000

5000

6000

Fig. 22. Smoothed (a + 2b + c)/4 ratios of total eharcoal. Charcoal A (25-50 microns), and Charcoal B (> 50 microns), to the pollen sum.

(Fig. 23). However, the ratio of aquatic to closely mirrors the juniper pollen percentage littoral plants continues to reflect water depth curve suggests that it does reflect the water as it did in the past. The fact that this ratio table (Fig. 24). 452 Great Basin Natueulist Vol. 47, No. 3

Macrofossils Between 6000 and 5400 B.P. Sarcuhatus (greasewood) pollen dominated the microfossil record. Its extreme abundance, up to 75% of the pollen sum, indicates that Sarco- hatus (black greasewood) and other salt- bushes, most likely Atriplex confertifolia (spiny saltbush) and Atriplex spinosa (spiny hopsage), covered the floor and lower slopes of Harney Basin. The preponderance of Sar- cobatus pollen suggests that saline soils char-

acterized the area (Branson et al. 1976).

The periodic occurrence of aquatic insects, algae, and finer sediments indicates that occasionally Malheur Maar supported ephemeral ponds. However, the absence of aquatic plant macrofossils suggests that the ponds were never permanent enough to maintain a growth of aquatic plants. The pond surface was seasonally at least 15-17 m below the present water surface of Diamond Pond. Be- cause Diamond Pond acts as a standpipe for the local water table, such lowered water tables suggest that marshes in the Harney Basin were greatly reduced in area and probably dry for much of the year. Intermittent beds of sands accumulated in Diamond Pond from the periodic erosion of the sparsely vegetated slopes of Malheur Maar. Sands and coarse silts washed into Diamond Pond along with pollen (Figs. 12, 25). Concentration of pollen from the slopes of the maar in sediments of the ephemeral shallow ponds at its bottom re- sulted in abnormally high pollen accumulation rates, especially in Zone 1 (Fig. 16). Clay clasts in many of the beds indicate intense but sporadic rainfalls. These data agree with the findings of others in the northern Great Basin concerning a dry mid-Holocene (Mehringer 1986, Davis 1982). On Steens Moimtain at Fish Lake abundant 1000 1500 2000 2500 3000 3500 4000 <500 5000 5500 nadlocBrbon Age B P sagebrush with respect to grass pollen between 8700 and 4700 B. P. reveals lower effec- Fig. 2.3. Numbers of suhinergecl, fmcr^ent, and littoral tive moisture than before or after, and sage- macrofossils e.xpressed as percent of the .55()()-year mean brush to grass ratios at Wildhorse Lake (1 = 100% on the scale). Ratio of acjuatic (submerged and emergent) to littoral plant macrofossils (scale on the left is indicate warmer temperatures (Mehringer the proportion). 1985:Fig. 12). A dramatic and totally unparalleled increase (within the Diamond Pond record) of The Environmental Record sagebrush pollen about 5300 B.P. indicates The record from Diamond Pond includes at the first in a series of wet periods that herald least 6200 years, of which the period between the end of mid-Holocene drought. However,

3600 and 2000 B.P. is revealed in detail because this event follows closely the fall of

unequaled in the northern Great Basin. the 5460 B.P. pumice, it is possible that the July 1987 WiGAND: Diamond Pond 453

POLLEN GRAMINEAE AQUATIC PLANT SEEDS « JUHIfESUS » CLAY A H T E It I S I A LITTORAL PLANT SEEDS

Fig. 24. Summary diagram incliidiiig, from left to right: (1) smootlied juniper pollen percentage, (2) radiocarbon dates on juniper macrofossils from packrat midden.s, (3) smoothed ratio of grass to sagebrush pollen, (4) ratio of aquatic to littoral plant macrofossils, (5) percent of cla\- per sediment sample.

pumice, by acting as a mulch, may have con- surrounded by a littoral community still domi- tributed to the spread of sagebrush. On the nated by bulrush and dock. other hand, because the increase was short- By 4-ioO B.P. the water table was within 10 lived, with greasewood soon the dominant m of its present level. Rising water table at plant again, it is more likely that a brief inter- Diamond Pond suggests that mid-Holocene val of greater effective moisture was the drought had given way to effectively moister cause. By 5000 B.P. greasewood was in full conditions. Resultant higher regional water retreat before the advance of other salt- tables would enable the Malheur Marshes to bushes, sagebrush, and grass. They continued expand into areas formerly occupied by their slow spread at the expense of grease- greasewood. This, together with the invasion wood until ca 3800 B. P. of other saltbush and sagebrush communities The appearance and sudden abundance of into the upper reaches of greasewood- littoral and aquatic plant macrofossils and dominated areas, may explain the sudden mollusk shells shortly before the fall of Tephra drop in Sarcohatus pollen values. IV (5460 B.P.) indicate that Malheur Maar Between 3750 and 2050 B.P. increased contained a relatively permanent body of wa- grass and juniper pollen values reflect the ter with lush aquatic growth. A marsh domi- spread ofjuniper and grass into sagebrush and nated by Scirpus acittus (hard-stem bulrush) shadscale communities around Diamond and Rumex maritimiis (seaside dock) was Pond (Fig. 24; Mehringer and Wigand 1987, quickly replaced by a permanent pond filled 1988). Charcoal proportions greater than be- with a variety of aquatic plants, primarily Cer- fore or after this period may evidence more atophyUum demersiim (hornwort). Poly- frequent fires resulting from more abundant gonum pcrsicaria (spotted smartweed), Zan- fuel. Low greasewood pollen values reflect nichellia palustris (horned pondweed), and the continued presence of marshes and salt- Potamogeton pusillus (small pondweed), and bush and sagebrush communities in areas pre- 454 Great Basin Naturalist Vol. 47, No. 3 100% SAND

50% \ / 50%

iXf. /''(20

— SHALLOW POND & MARSH 1 293 I410,» • • / ••1426 6? ^ • 1487 • > ' /• DEEP POND / , 1415 e'l029\l11d 468 , . » '^ai ••669 100% / \ . ^1443 '^V.* 100% SILT 1494 523 /\ CLAY 50%

Fig. 25. Proportions of sand, silt, and clay in Diamond Pond sediments and their relationships to water depth as suggested by plant fossils. Numbers indicate sediment depth in centimeters (Fig. 12).

viously occupied by greasewood. From 3800 Abundant rockfall in pond sediments of this to 3600 B.P. high juniper and grass pollen period, especially after ca 3200 B.P., may re- values, also reflected in the pollen ratios, cor- flect accelerated freeze/thaw activity resulting respond to the greatest abundance of sub- from colder temperatures or greater effective merged and floating aquatic plants as com- moisture. Because these rocks are found en- pared to littoral species. The water table may closed in fine sediment near the center of the

have risen more quickly than the accumula- pond, it is possible that they fell onto ice when

tion of sediment in Diamond Pond to make it the pond was frozen and were dropped when deeper than at any other time. Proportions of the ice melted. clay in excess of 25% also suggest deep water Shortly before the fall of the 2845 B.P. vol- (Figs. 12, 25). canic ash (Tephra III), finely laminated pond Throughout the Great Basin, rising lake deposits are interrupted by a unit of crumb levels and changing plant commimities evi- structure with numerous salt crystals and the dence alleviation of the mid-Holocene warm largest carbonate percentage in the Diamond period (Mehringer 1986, Davis 1982). Inten- Pond record. A corresponding sharp increase sive human occupation of Hidden (Thomas et of greasewood pollen values, decreased al. 1985) and Krammer (Hattori 1982) caves aquatic plant macrofossils, but more abundant between 3800 and 3600 B.P., with corre- littoral plant macrofossils support the sugges- sponding extensive use of marsh plants and tion of a brief but significant drought. animals, indicates that marshes had reap- Except during this drought, submerged peared near these sites. and floating aquatic plants dominate the July 1987 VViciAND: Diamond Pond 455 macrofossil record between 4000 and 2000 other sediments from Zone 3 (Figs. 12, 25). In B.P. and indicate at least five periods of addition, pollen accumulation rates between deeper water (Figs. 23, 24). Following the 800 and 450 B.P. (Fig. 16) are abnormally pre-Tephra IV drought, several aquatic spe- high. Both factors suggest decreased vegeta- cies either disappeared (Polygonum persi- tion cover and increased erosion of the slopes caria) or became more rare (CcratopJu/Ihim of Malheur Maar. demcrsum). Less-abimdant floating and sub- Greater values of grass and juniper pollen merged aquatic plants alter 2600 B.P. reflect about 300 B.P. indicate a return to effectively the transition to a shallower pond due both to wetter conditions. This is supported by finer sediment accumulation in the maar and drier sediment, indicating deeper water (Figs. 12, conditions. After ca 2050 B.P. both the sharp 25), and by increased submerged and floating decline of floating and submerged aquatic aquatic plant macrofossils, especially Cerato- plant macrofossils with respect to macrofossils phijUum demersiim (Fig. 19). Aquatic plant of littoral plant and the dramatic tall oi juniper abundance is further supported by the pres- and grass pollen values probably reflect a drop ence of large numbers oiFlanorhcUa and Gy- in the water table due to drier conditions. raiilus snails, which favor thick aquatic vege- Following 2000 B.P. declining juniper and tation. Becently, more abundant sagebrush grass pollen values may reflect their retreat to pollen and declining juniper and grass values the higher northern parts of Diamond Craters may result from a combination of fire suppres- where water perched in the shallow soils over- sion, water diversion, overgrazing, and log- lying the basalt flows and a north-focing aspect ging, as well as changing climate. favored their survival. The sagebrush under- Despite the accumulation of at least 15 m of story replaced them as the dominant vegeta- sediment during the past 6000 years, a rising tion. Increased values of juniper and grass water table has maintained the pond. How- pollen indicate expansion of grass and juniper ever, the trend from aquatic to littoral plant ca 1600 B.P., between ca 1400 B.P. and 700 dominance reflects the long-term filling of Di-

B. P. , and between ca 450 and 200 B.P. Abun- amond Pond that will eventually terminate its dant grass characterizes the period between existence. ca 1400 and 700 B. P. , while juniper has only a brief increase about 900 B.P. Harper and Conclusion Alder (1970, 1972) record a significant moist intei-val between 1500 and 600 B.P. Kelso The detail available in the pollen and (1970) inferred, from pollen data, a moist macrofossil records from Diamond Pond, es- period dominated bv grass beginning about pecially between 4000 and 2000 B.P., has al- 1500 B.P. lowed resolution of major climatic episodes Dominance of littoral plant macrofossils in lasting only one or two centuries with transi- Diamond Pond indicates that water levels re- tions of less than 25 to 40 years (Fig. 24). mained low through the first part of this pe- Relative pollen frequencies from Diamond riod. About 900 to 800 B.P. more abundant Pond mirror the response of dominant plant submerged and floating a(iuatic plant macro- species of the local and regional plant commu- fossils and greater juniper pollen percentages nities to long- and short-term climatic change evidence effectively moister conditions. since the mid-Holocene. Aquatic and littoral Greater proportions of clay in the pond sedi- plant macrofossils record details of fluctuating ments also suggest deep water ca 1400 and water depth of Diamond Pond, as well as the again ca 1000 B.P. (Figs. 12, 25). long-term infilling of Diamond Pond. Because After 700 B.P. at least two major droughts, aquatic and littoral plants spread and mature one about 700 and another about 500 B. P. , are rapidly, they are sensitive indicators of chang- indicated by increased values of greasewood. ing effective moisture. The occurrence of Riippio pollen and seeds If the aquatic to littoral plant macrofossil and the appearance of the fingernail clam, ratio is an accurate indication of fluctuating Musculium securis, indicate that Diamond water table and, by extension, expansion of

Pond was more saline and dried out periodi- the Malheur marshes, it seems that they were cally. Analysis of at least one sample from this most extensive between ca 3750 and 3450 period showed sediments higher in sand than B.P. From ca 2800 to 2050, 1000 to 800, and 456 Great Basin Naturalist Vol. 47, No. 3

300 to 150 B.P., more abundant aquatic plant Bentley, E B 1970. The glacial geomorphology of Steens Mountain, Oregon. Unpublished thesis. macrofossils indicate recharged local water University of Oregon, Eugene. 98 pp. table and marsh reexpansion. Major littoral 1974. The glacial morphology of eastern Oregon plant increases about 2900 and 500 B.P. indi- uplands. Unpublished dissertation. University of cate severe drought. Oregon, Eugene. 2.50 pp. Berggren. G. 1969. Atlas of seeds and small fruits of northwest-European plant species with morpho- Acknowledgments logical descriptions. Part 2: Cyperaceae. Berlingska Boktrycherict, Lund. 107 pp. is a This study abstracted from dissertation BiRKS, H H , AND R W Mathewes 1978. Studies in in the Department of Anthropology at Wash- vegetational history of Scotland. V, Late Deven- sian and early P^landrian pollen and macrofossil ington State University. It was initiated as stratigraphy at Abernathy Forest, Inverness- part of the Steens Mountain Prehistory Proj- shire. New Phytology 80: 455-484. ect supported in part by National Science Black.C A , ED 1965. Methods of soil analysis. American Foundation Grants BNS-V7-12556 and BNS- Society Agronomy, Monograph 9. 2 vols. 80-06277 and completed while being partially Madison, Wisconsin. 1,572 pp.

supported by a Bureau of Land Management Branson, F. A , R F. Miller, and I. S McQueen 1976. Moisture relationships in twelve northern desert grant to study juniper history. Dr. P. J. communities near Grand Junction, Colorado.

Mehringer, Jr., recognized the regional Ecology .57(6): 1104-1124. paleoenvironmental potentials of the Steens Braymen, P 1984. Corps, county will study canal plan to Mountain area over a decade ago and has car- drain Harnev lakes. The Oregonian, Tuesday, 8 May 1984, 134(.38): B3. ried on a series of studies that include past

Bright, R C , andO K Davis 1982. Quaternary paleo- vegetation history, volcanic ash chronology, ecology of the Idaho National Engineering Labo- paleomagnetic studies, and regional Holo- ratorv. Snake River Plain, Idaho. Amer. Mid. Nat. cene stratigraphy. Dr. Mehringer was also 108(1): 21-33. chairman of my dissertation committee when Brown, G B III. 1980. Geologic and mineral resources of the Diamond Craters volcanic complex, Harney this study was completed. Chad Bacon, County, Oregon, with comparative data for se- Wilbert Bright, and George Brown of the Bu- lected areas of volcanism in Oregon and Idaho. reau of Land Management (BLM), Burns of- U.S. Bureau of Land Management, Oregon. .30 fice, provided enthusiastic support. BLM pp. botanists Esther Gruber and Joan Price and Clark. R C 19.32, Harney Basin exploration, 1826-60. Oregon Historical Quarterly 33(2): 101-114. ecologist Ellen Benedict shared their special Cric:k, R 1983. Eastern Oregon floods bring ranchers knowledge of Diamond Graters. K. L. Pe- J closer to ruin. The Sundav Oregonian, 24 April tersen, members of the Steens Mountain Pre- 1983, 102(21): Al.

history summer field school and of Dr. Gushing, E J., and H E. Wright, Jr. 1965. Hand- Mehringer's Washington State University fall operated piston corers for lake sediments. Ecology 46(3): 380-384. 1978 palynology class helped core Diamond

Davies, K G , A M, Johnson, and D O Johansen, eds. Pond. Kate Aasen and Mary Ann Mehringer 1961. Peter Skene Ogden's Snake Country journal helped collect plants. Joy Mastroguiseppe, 1826-27. The Hudson's Bay Record Society, Lon- Steve Gill, and Richard Old of the Marion don. 255 pp. Da\ts, 1982. Bits and pieces: the last 35,000 years in Owenby Herbarium confirmed many plant J O the Lahontan area. Pages .53-75 in D. B. Madsen identifications. Dr. D. W. Taylor identified and F. O Connell, eds., Man and environment the mollusks. Teberg helped with com- J. John in the Great Basin. Society for American Archaeol- puter analysis and plotting, and Karla Kalasz ogy, SAA Papers 2. Washington, D.C. and Derise Wigand helped draft figures. Davis, O K 1981. Vegetation migration in southern Idaho during the Late-Quaternary and Holocene. Unpublished dissertation, Lhiiversity of Minne- Literature Gited sota, Minneapolis. 252 pp. 1984. Pollen frecjuencies reflect vegetation patterns in a Great Basin (U.S.A.) mountain range. Baker, V R , G. Pickup, and H. A Polach 1985. Radio- carbon dating of flood events, Katlierine Gorge, Review of Palaeobotanv and Palynology 40(4): Northern Territory, Australia. Geologv 13: 344- 295-315.

347. Dean, W E , Jr 1974. Determination of carbonate and sedi- Bartholomew, M. J. 1982. Pollen and sediment analyses organic matter in calcareous sediments and of Clear Lake, Whitman County, Washington; the mentary rocks by loss on ignition: comparison with last 600 years. Unpublished thesis, Washington other methods. Journal of Sedimentary Petrology State University, Pullman. 81 pp. 44(1): 242-248. July 198' WiCAND: Diamond Pond 457

FaECKI, K 1966. A botanical excursion to Stecns Moun- Kol\ A, D A 1975. Exploratorv' palynology of a Scabland tain, S.E. Oregon, U.S.A. Saertrvkk a\ Bl\ttia24: Lake, Whitman County, Washington. Unpub- 173-181. lished thesis, Washington State University, Pull- Ferguson, D., .\nd N. Ferguson 1978. Oregon's Great man. 43 pp. Basin country. Gail Graphics, Biuns, Oregon. 178 Kru.MBEIN, W C 1934, Size frecjuency distributions of pp. sediments. Journal of Sedimentary Petrology 4(2): Fletcher, M. R andW B Cl.m'iia\i Jk 1974. Sediment 65-77, densit}' and the limits to the repeatability of abso- Likens, G. E., .\nd M B. Davis. 1975. Postglacial history lute pollen frecjuencv determinations. Geoscience of Mirror Lake and its watershed in New Hamp- and Man 9: 27-35. shire, U.S.A.: an initial report. Verhandlungen

Folk, R. L , and W. C. Ward. 1957. Brazos River bar: a des Internationalen Verein des Limnologie 19: study in the significance of grain size parameters. 982-993. Joiunal of Sedimentar>- Petrology 27(1): 3-26. Mairs, W. 1977. Plant communities of the Steens Fuller, R. E 1931. The geomorphology and volcanic J. Mountain subalpine grassland and their relation- sequence of Steens Mountain in southeastern Or- ship to certain environmental elements. Unpub- egon. University of Washington Publications in lished dissertation, Oregon State University, Cor- Geology 3(1): 1-130. vallis. 195 pp. Haines, F D , Jr , ED 1971. The Snake Country Expedi- Martin, A, and W. D. Barkley. 1961. Seed identification tion of 1830-1831: John Work's field journal. Uni- manual. Uni\ersitv of California Press, Berkeley. versity of Oklahoma Press, Norman. 163 pp. 221 Hansen, C. G. 1956. An ecological surve\' of the verte- pp. R. brate animals on Steens Moiuitain, Harnes' Martin, J., and E. Corbin, eds. 1931. Climatic sum- County, Oregon. Unpublished dissertation, Ore- mary of the United States, Sect. 4—eastern Ore- gon State College, Cor\allis. 199 pp. gon. U.S. Department of Agriculture, Weather Bureau. 29 Harper, K. T . and G M Alder 1970. Appendix 1: The pp.

macroscopic plant remains of the deposits of Mehringer, P J . Jr 1967. Pollen analysis of the Tule Hogup Cave, Utah, and their paleoclimatic impli- Springs area, Ne\ada. Pages 129-200 in H. M. cations. Pages 215-240 in C. M. Aikens, Hogup Wormington and D. Ellis, eds., Nevada State Mu- Cave. University of Utah Anthropological Papers seum Anthropological Papers 13.

93. 1977. Great Basin late Quaternarv' environments 1972. Paleoclimatic inferences concerning last the and chronolog}'. Pages 113-167 i?i D. D. Fowler, 10,000 years from a resampling of Danger Cave, ed.. Models and Great Basin prehistory: a sympo- Utah. Pages 13-23 in D. Fowler, ed.. Great Basin sium. Desert Research Institute Publications in cultural ecology: a symposium. Desert Research the Social Sciences 11. Institute Publications in the Social Sciences 8. 1985. Late-Quaternar\' pollen records from the H.\TTORL E. 1982. The archaeology of Falcon Hill, M interior Pacific Northwest and northern Great Winnemucca Lake, Washoe Coimty, Nevada. Ne- Basin of the United States. Pages 165-187 in V. A. vada State Museum Anthropological Papers 18. Bryant and R. G. Holloway, eds.. Pollen records 208 pp. of Late-Quaternary North American sediments. Henry, 1984. Holocene paleoecology of the western C American Association of Stratigraphic Palynolo- Snake River plain, Idaho. Unpublished thesis. gists, Dallas, Texas. University of Michigan, Ann Arbor. 156 pp. 1986. Past environment. Pages 31-50 in W. L. HOLLOWAY, L. 1958. Smoothing and filtering of time J d Azevedo, ed.. Handbook of North American In- series and space fields. Advances in Geophysics 4: dians: Great Basin. Smithsonian Institution, 351-388. Washington, D.C. Hubbard, L. L. 1975. Hydrology of Malheur Lake, Har- Mehringer, P. C. Sheppard. 1978, Holocene ney County, southeastern Oregon. U.S. Geologi- J.,Jr.,andJ. history of Little Lake, Mohave Desert, California. cal Survey Water Resources Investigations 21-75, Pages 153-166 in E. L. Davis, ed.. The ancient Portland, Oregon. 40 pp. Californians: Rancholabrean hunters of the Mo- Jeppesen, D J 1978. Competitive moisture consumption have Lakes country. Natiu'al History Museum of by the western juniper (Juuiperus occidctitalis). Los Angeles County, Science Series 29. Pages 83-90 in Proceedings of the western juniper

ecology and management workshop. Bend, Ore- Mehringer. P J , Jr . J C Sheppard, L. Kittleman, and gon, January 1977. U.S. Department of Agricul- C Knowles 1987, Holocene tephrochronology of ture, Forest Service General Technical Report the Steens Mountain region, southeastern Ore- PNW-74. Pacific Northwest Forest and Range Ex- gon. Manuscript in preparation.

periment Station, Portland, Oregon, Mehringer, P J., Jr., and P. E. Wigand. 1985. Prehis- toric distribution of western juniper. Pages 1-9 in Katz. N 1 , S V K.\Ti. and M G Kipl^nnl 1965. Atlas i

opredlitel plodov i semian, vstrechaiushchikhia v Proceedings of the western juniper management chet\ertichnykh otlozheniiakh SSSR. Akademiia short course. Bend, Oregon, 15-16 October 1984. Naiuk SSSR, Moscow. 365 pp. Oregon State Unisersity Extension Service and Kelso, G K 1970. Appendix 1\': Hogup Cave, Utah: the Department of Rangeland Resources, Oregon comparative pollen anal\ sis of human coprolites State University, Corvallis.

and cave fill. Pages 251-262 in C. M. Aikens, 1986. Holocene history of Skull Creek Dunes, Hogup Cave. Universit\' of Utah Anthropological Catlow Valley, Oregon, U.S.A. Journal of Arid Papers 93. Environments 11: 117-138. 458 Great Basin Naturalist Vol. 47, No. 3

1987. Western juniper in the Holocene. In: Pro- Smith, W D 1924. The physical and economic geography ceedings of the pinyon-juniper conference, Reno, of Oregon. Commonwealth Review of the Univer- Nevada, 13-16 January 1986. General Technical sity of Oregon 7(4); 1.57-194. Report INT-215. llpp'. Soil Sl'RVEY Staff 1951. Soil survey manual. U.S. De- 1988. Comparison of Late Holocene environ- partment of Agriculture, Handbook 18. .503 pp. ments from woodrat middens and pollen. Dia- Sternes.G L 1960. Climates of the states. Oregon. U.S. mond Craters, Oregon. In: P. S. Martin, T. R. Department of Commerce, Weather Bureau. Cli-

Van Devender, and J. L. Betancourt, eds.. Fossil matography of the United States No. 60-.35. 20 packrat middens: the last 40,000 years of biotic pp. change. Lhiiversity of Arizona Press, Tucson. Stockmarr, J 1971. Tablets with spores used in absolute 1977. Seeds and fruits of plants of Montgomery, F H pollen analysis. Pollen et Spores 13(4); 615-621. eastern Canada and northeastern United States. Uni- 1973. Determination of spore concentration with versity of Toronto Press, Toronto, Canada. 232 pp. an electronic particle counter. Pages 87-89 in MunsellSoilColorChakts 1975. Munsell color. Mac- Danmarks Geologiske Undersgelse, Arbog 1972. beth Division of Kollmorgen Corporation, Balti- Thomas, D. H.. etal 1985. The archaeology of Hidden more, Maryland. 10 pp. Cave. Anthropological Papers of the American MusiL, A. F. 1978. Identification of crop and weed seeds. Museum of Natural History 61(1). 430 pp. U.S. Department of Agriculture, Handliook 219. US Department of Commerce. Weather Bureau. 171 pp. 19.53. Climatic siunmary of the United States: Or- Orloci. L 1967. An agglomerative method for classifica- egon—supplement for 1931 through 1952. Cli- tion of plant commiuiities. Journal of Ecologv matography of the United States No. 11-31. 70 55(1); 193-206. pp. Peter, D H 1977. Analysis of tree rings oi Juniperus 19.54-1984. Climatological data Oregon: annual occidentalis from southeastern Oregon. L^npub- — summary. No. 13 in each of Vols. 60-90. lished thesis, Washington State Lhiiversity, Pull- Urban, K A 1973. Vegetative patterns on Steens Moun- man. 89 pp. tain, Harney County, Oregon. Blue Mountain Petersen, K L 1981. 10,000 years of climatic change Community College, Pendleton, Oregon. Unpub- reconstructed from fossil pollen. La Plata Moun- lished manuscript. .35 tains, southwestern Colorado. Lhipublished dis- pp. sertation, Washington State L'niversitv, Pullman. Walker, G W 1979. Revisions to the Cenozoic stratigraphy of Harney Basin, southeastern Oregon. U.S. 197 pp. Geological Bulletin 1475. Peterson, N. V., and E A. Ghoh 1964. Diamond Survey, 35 pp. Craters, Oregon. Ore Bin 26(2); 17-33. Walker. G W., and D A Swanson 1968. Summary report on the geology and mineral resources of the Piper, A M . T W Robinson, and C. F. Park. Jr 1939. Geology and ground-water resources of the Har- Harney Lake and Malheur Lake areas of the Mal- ney Basin, Oregon. U.S. Geological Siirvev, heur National Wildlife Refuge, north-central Har- Water-Supply Paper 841. 189 pp. ney Count)', Oregon, and Poker Jim Ridge and Price, L. W. 1978. Mountains of the Pacific Northwest, Fort Warner areas of the Hart Mountain National U.S.A.; a study in contrasts. Arctic and Alpine Antelope Refuge, Lake County, Oregon. L^S. Ge- Research 10(2);'465-478. ological Survey, Bulletin 1260-L. 17 pp. Waring, A. 1909. Geology and water resources of the Rich, E E , A M Johnson, and B B Barker, eds 1950. G Peter Skene Ogden s Snake Country journals Harney Basin, Oregon. U.S. Geological Survey, 1824-25 and 1825-26. The Hudson's Bay Record Water-Supply Paper 231. 93 pp. Society, London. 283 pp. Williams. G,, D E Miller, and D H. Miller, eds.

Russell. I. C 1903. Notes on the geology of southwestern 1971. Peter Skene Ogden's Snake Coimtry jour- Idaho and southeastern Oregon. U.S. Geological nals 1827-28 and 1828-29. The Hudson's Bay Survey Bulletin 217. 83 pp. Record Society, London. 201 pp.

1905. Preliminary report on the geology and water Young, J A, and R. A. Evans 1981. Demography and fire resource of central Oregon. U.S. Geological Sur- historv of a western juniper stand. Journal of vey Bulletin 252. 138 pp. Range Management 34(6); 501-,506.