River Range Research Articles

Where the Morning Light’s Still Blue: Personal Essays About Idaho ed. by William Studebaker, Rick Ardinger

Reviews Where the Morning Light’ s Still Blue: Personal Essays About Idaho. Edited by William Studebaker and Rick Ardinger. (Moscow: University of Idaho Press, 1994. 200 pages, $15.95.) This collection of thirty-five essays focuses on what it means to thirty writers to live in Idaho and to engage with its landscape and with the changes that are being imposed on it from inside and out­ side. Among those collected is Robert Wrigley, who knows that belonging to Lewiston has meant having “a resource of immeasur­ able value” physically and imaginatively; and Gino Sky, whose “Rhymes Creek” is a refuge from “that place called the real world, where life goes on with its endless hunger for freeways and aggres­ sive neon.” Idaho is also the place of writers like Bill Hall, who understands that the state is all too attractive to outsiders eager to impose their own misguided values on their new home; John Rember, who feels the loss of the wild Sawtooth Valley even though his family benefited from the new roads that were built; and Mary Clearman Blew, who now must ride horses with her daughter above new subdivisions spoiling the land. The writers gathered here tell us of a place that is like no other in our nation, and all too much like every other wild place overrun by “civilization.” Here are the writers of the last frontier, “geo­ graphic or symbolic,” as the editors say. They have been fortunate to write from a largely unspoiled place; and yet they have been unfor­ tunate in having to document its diminishment and its possible loss. Their story is the story of the West, and of our nation. In editing this significant collection, Studebaker and Ardinger have brought to readers a record of the brilliance of Idaho’s writers, 392 Western American Literature few of whom will be known to a national audience; but even more important is how they have added thirty more voices to those of William Kittredge and Gary Snyder, westerners who have shown, if anything, that the true battle for our nation’s soul is being waged on western soil; and who warn that if we are to survive, we must learn, as these writers have learned, how to live in a place where we belong to the land. KEVIN BEZNER Livingstone College TumbleWords: Writers Reading the West. Edited by William L. Fox. (Reno: University of Nevada Press, 1995. 380 pages, $20.00.) TumbleWords is the culmination of a writing project begun in 1991 with an “underserved community” grant in Idaho, Utah, and Wyoming. In 1993, the project expanded to include writers in Arizona, Colorado, Montana, Nevada, and New Mexico. One of the goals of the project was to create new audiences for literature, so I entered the text wondering just what it might be in this collection that would indeed approach this goal. Well, as Fox himself says, the writings cannot be defined as avant-garde. In attending to the aforementioned goal, Fox did not want “to puzzle or challenge” the audience. To rope off a segment of the western United States and then approach their literary needs with less than full respect for their intellectual capacity for the complications of con­ temporary literature is absurd. Life in the western states is no less complex than life anywhere in the world. For writers to resort to only “reconnecting . . . local audience[s] with their own memories and voices” can perhaps only be an exercise in sentimentality. Nevertheless there are challenges to be met in the work of the seventy-two writers relegated to the task of mirroring those whom Fox seems to label as less than sophisticated. Ron McFarland from Idaho, in his “At the Correctional Facility,” considers the need for words that might add up to a form for perhaps understanding and getting out of the defeat of a life of crime. From her cabin in Utah’s Bear River Range, Kate Boyes’s essay “I Hold with Those Who Favor Fire” trails through memories of growing up in the sixties to ...

The ability of pollen from small lakes and ponds to sense fine-scale vegetation patterns in the Central Rocky Mountains, USA

Pollen ratios and linear discriminant analysis were used to detect fine-scale vegetation patterns in the subalpine zone of the central Rocky Mountains, USA. The vegetation of this zone is a mosaic of conifer forests and treeless parks dominated by sagebrush ( Artemisia spp.) and grasses. Previous work with pollen surface samples in the region has correlated modern pollen rain to broad-scale vegetation zones (e.g. steppe, montane forest, subalpine forest, and tundra), but little effort has been made to detect fine-scale (hundreds to thousands of meters) patterns within these vegetation zones. Previous theoretical studies suggest that vegetation patterns on the scale of hundreds of meters should be recorded in the pollen deposited in small ponds. Pollen surface samples were collected from small ponds and lakes (30–350 m diameter) from subalpine vegetation in Colorado and Wyoming. An additional set of samples was collected from small ponds in a park and the surrounding forest in the Wind River Range of northwest Wyoming. Pollen percentages were not dramatically different in park and forest assemblages, but the ratio of conifer to herb and Artemisia pollen (C:H) and the linear discriminant score were successful in separating park and forest pollen assemblages.

Taphonomy and Time Resolution of Bone Assemblages in a Contemporary Fluvial System: The East Fork River, Wyoming

Experiments that recorded the dispersal of 142 bones within a meandering, 2030 m-long reach of the East Fork River, Wyoming over a 13-year period provide a basis for interpreting distribution patterns and time averaging in fossiliferous channel deposits. Results show that light and porous bones, (e.g., vertebrae, patellae, and phalanges) were transported farther than heavy bones (e.g., limb bones and mandibles). Dispersal patterns of bones from individual experimental sets representing point sources demonstrate that bones became sorted by size and shape within 1 to 2 years and that sorting patterns varied according to initial channel position. The combined distribution of bones from all the experimental sets, however, was unsorted and generally random, suggesting that unsorted fluvial bone assemblages reflect multiple bone sources and differences in the time at which bones enter the channel. Estimates of time-averaging of potential and observed natural bone assemblages in the East Fork River and the South Platte River range from 101-104 years. The upper limit for this estimate is controlled by both the age offossiliferous floodplain deposits that border the rivers and by the ability of the rivers to rework these floodplain deposits. The lower limit reflects either the scarcity of bones in the floodplain sediments or the inability of the rivers to rework these older bones; in this case channel bone assemblages should represent only remains from deaths in the channel or remains that were transported into the channel from adjoining land surfaces, resulting in short intervals of time-averaging (101-102years). The East Fork study further suggests that sandstone geometry, paleosol development, and the sedimentary context

A Two-Year Record of Eolian Sedimentation in the Wind River Range, Wyoming, U.S.A.

A Two-Year Record of Eolian Sedimentation in the Wind River Range, Wyoming, U.S.A.

A Two-Year Record of Eolian Sedimentation in the Wind River Range, Wyoming, U.S.A.

Eolian sediment collected at three locations in the Wind River Range at seven seasonal intervals from December 1988 to October 1990 were used as a baseline from which to estimate the effects of eolian sedimentation in this region. Dust was collected from snow- and rain-catch instruments installed by the US Forest Service at Hobbs Lake, Lester Pass, and Black Joe Lake. These data show that dust influx rates varied from 0.23 to 31.0 x 10{sup -7}g cm{sup -2} d{sup -1} during the sampling period. The highest sedimentation rates occur during the late summer from July through September and the lowest rates occur during the winter. High influx rates during the summer months apparently reflect the dry, snow-free conditions in the adjacent Green River Basin, from which much of the eolian sediment originates. Accumulations of dust that originates outside the Wind River Range may affect the ability of soils and sediments of the range to buffer increases in SO{sub 4} and NO{sub 3} deposition. 21 refs., 5 figs., 2 tabs.

Little Ice Age Evidence from a South-Central North American Ice Core, U.S.A.

In the past, ice-core records from mid-latitude glaciers in alpine areas of the continental United States were considered to be poor candidates for paleoclimate records because of the influence of meltwater on isotopic stratigraphy. To evaluate the existence of reliable paleoclimatic records, a 160-m ice core, containing about 250 yr of record was obtained from Upper Fremont Glacier, at an altitude of 4000 m in the Wind River Range of south-central North America. The {gamma}{sup 18}O (SMOW) profile from the core shows a -0.95{per_thousand} shift to lighter values in the interval from 101.8 to 150 m below the surface, corresponding to the latter part of the Little Ice Age (LIA). Numerous high-amplitude oscillations in the section of the core from 101.8 to 150 m cannot be explained by site-specific lateral variability and probably reflect increased seasonality or better preservation of annual signals as a result of prolonged cooler temperatures that existed in this alpine setting. An abrupt decrease in these large amplitude oscillations at the 101.8-m depth suggests a sudden termination of this period of lower temperatures which generally coincides with the termination of the LIA. Three common features in the {gamma}{sup 18}O profiles between Upper Fremont Glacier and themore » better dated Quelccaya Ice Cap cores indicate a global paleoclimate linkage, further supporting the first documented occurrence of the LIA in an ice-core record from a temperate glacier in south-central North America.« less

The role of inclusions in U-Pb and Sm-Nd garnet geochronology: Stepwise dissolution experiments and trace uranium mapping by fission track analysis

The U-Pb and Sm-Nd dating of garnet are important tools for understanding rates of tectonometamorphic processes and have been widely applied in studies of metamorphic terranes. However, the budgets of uranium, lead, samarium, and neodymium in garnet separates from metamorphic rocks may be dominated by contributions from inclusions of monazite or zircon. A combined fission track and stepwise dissolution technique is proposed for evaluating the role of inclusions of monazite and zircon in the budgets of uranium, lead, samarium, and neodymium in garnets used for U-Pb and Sm-Nd chronology. Variations of Th/U, U/Nd, and Sm/Nd ratios between successive dissolution steps reveal the contributions of monazite and zircon inclusions. The stepwise dissolution procedure does not induce any apparent artifacts on 207Pb- 206Pb and Sm-Nd ages. The technique has been applied to garnets from three metamorphic terranes. Almandine garnet samples from the high grade Pikwitonei Granulite Domain (Manitoba, Canada) and the Wind River Range (Wyoming, USA) have the majority of their uranium, samarium, neodymium, and radiogenic lead (Pb*) hosted by micrometer-scale inclusions of monazite. Fission track densities reveal that uranium is 10 8 times more abundant in inclusions than in garnets. Stepwise dissolution of the samples shows that neodymium and uranium are associated with the dissolution of monazite. In contrast, grossularandradite garnets from Cascade Slide (Adirondack Highlands, NY, USA) show little variation in fission track density and similar isotopic ratios between dissolution steps, indicating that the budgets of uranium, samarium, neodymium, and Pb * are not significantly influenced by inclusions. The demonstrated success of these techniques leads us to recommend similar procedures as a routine matter in U-Pb and Sm-Nd garnet geochronology of metasedimentary rocks.

Mesoscale Variability of the Upper Colorado River Snowpack

In the mountainous regions of the Upper Colorado River Basin, snow course observations give local measurements of snow water equivalent, which can be used to estimate regional averages of snow conditions. We develop a statistical technique to estimate the mesoscale average snow accumulation, using 8 years of snow course observations. For each of three major snow accumulation regions in the Upper Colorado River Basin – the Colorado Rocky Mountains, Colorado, the Uinta Mountains, Utah, and the Wind River Range, Wyoming – the snow course observations yield a correlation length scale of 38 km, 46 km, and 116 km respectively. This is the scale for which the snow course data at different sites are correlated with 70 per cent correlation. This correlation of snow accumulation over large distances allows for the estimation of the snow water equivalent on a mesoscale basis. With the snow course data binned into 1/4° latitude by 1/4° longitude pixels, an error analysis shows the following: for no snow course data in a given pixel, the uncertainty in the water equivalent estimate reaches 50 cm; that is, the climatological variability. However, as the number of snow courses in a pixel increases the uncertainty decreases, and approaches 5-10 cm when there are five snow courses in a pixel.

Insights into alpine moraine development from cosmogenic 36Cl buildup dating

We have used cosmogenic 36Cl surface exposure dating to determine apparent construction ages of late Pleistocene moraines in the Sierra Nevada, the White Mountains, and the Wind River Range, all in the western United States. The inferred glacial chronologies from the various localities all exhibit certain characteristics: (1) Local records are fragmentary and deposits of some glacial advances are always missing; no location has deposits of all glaciations and no glacial advance is recorded at all locations. This is due either to unfavorable conditions for glacier development at some times or to obliteration of earlier deposits by later, more extensive glaciers. (2) Most moraines have young apparent exposure ages, with only a few older than the last glacial cycle. This may be due to young true ages of these deposits, erosion of moraine surfaces, or obliterative overlap and covering of older deposits by younger ones. (3) Many deposits that were previously correlated (e.g., based on their stratigraphic positions) are not correlative; they may represent different stades and, sometimes, even different glaciations. Similarly, some previously uncorrelated deposits have the same exposure ages and may be correlative. (4) Clusters of several distinct moraines of nearly the same age are present at most locations. These clusters suggest that alpine moraines are formed during short deposition episodes that last between several hundred and several thousand years.

Isozyme variation in New Zealand populations of Myriophyllum and Potamogeton species

Isozymes of six freshwater angiosperm species were examined as a measure of genetic variation within and between populations. Five species ( Myriophyllum triphyllum Orchard, Myriophyllum propinquum A. Cunn., Myriophyllum pedunculatum Hook. f., Potamogeton cheesemanii A. Benn., and Potamogeton ochreatus Raoul) are native to New Zealand, while Potamogeton crispus L., is adventive. Species were collected from a wide geographic range of lakes and rivers throughout New Zealand. Myriophyllum triphyllum, Myriophyllum propinquum and Myriophyllum pedunculatum were sampled from 23, 18 and five lakes respectively, while Potamogeton cheesemanii, Potamogeton ochreatus and Potamogeton crispus were collected from a total of 12, nine and four water bodies, respectively. The plants were grown under uniform conditions prior to analysis and analysed by starch gel electrophoresis for the following enzyme systems: PGM, PGD, MDH, GPI, AAT, EST, and IDH. All species studied showed little isozyme genetic diversity between populations and even less variability within populations. On a relative scale, Myriophyllum propinquum displayed the largest degree of genetic differentiation, Myriophyllum pedunculatum and all three Potamogeton spp. were moderately variable, and Myriophyllum triphyllum showed the lowest level of diversity. There was a close correlation between the amounts of intra- and interpopulation genetic variability in all species. No association between geographic and genetic distances between populations could be found for any of the species examined, and the patterns of distribution of isozyme phenotypes and genotypes over populations suggest that populations are often started by a single colonising propagule, or several propagules of identical genotype, and then predominantly grow through vegetative propagation. The apparent lack of genetic variability indicated by the results of this study is consistent with low levels of variability observed amongst aquatic macrophytes in other countries.

Beryllium-10 Dating of the Duration and Retreat of the Last Pinedale Glacial Sequence

Accurate terrestrial glacial chronologies are needed for comparison with the marine record to establish the dynamics of global climate change during transitions from glacial to interglacial regimes. Cosmogenic beryllium-10 measurements in the Wind River Range indicate that the last glacial maximum (marine oxygen isotope stage 2) was achieved there by 21,700 +/- 700 beryllium-10 years and lasted 5900 years. Ages of a sequence of recessional moraines and striated bedrock surfaces show that the initial deglaciation was rapid and that the entire glacial system retreated 33 kilometers to the cirque basin by 12,100 +/- 500 beryllium-10 years.

Late Quaternary Vegetation and Climate of the Wind River Range, Wyoming

Sediments from Rapid Lake document glacial and vegetation history in the Temple Lake valley of the Wind River Range, Wyoming over the past 11,000 to 12,000 yr. Radiocarbon age determinations on basal detrital organic matter from Rapid Lake (11,770 ± 710 yr B.P.) and Temple Lake (11,400 ± 630 yr B.P.) bracket the age of the Temple Lake moraine, suggesting that the moraine formed in the late Pleistocene. This terminal Pleistocene readvance may be represented at lower elevations by the expansion of forest into intermontane basins 12,000 to 10,000 yr B.P. Vegetation in the Wind River Range responded to changing environmental conditions at the end of the Pleistocene. Following deglaciation, alpine tundra in the Temple Lake valley was replaced by a Pinus albicaulis parkland by about 11,300 14C yr B.P. Picea and Abies, established by 10,600 14C yr B.P., grew with Pinus albicaulis in a mixed conifer forest at and up to 100 m above Rapid Lake for most of the Holocene. Middle Holocene summer temperatures were about 1.5°C warmer than today. By about 5400 14C yr B.P. Pinus albicaulis and Abies became less prominent at upper treeline because of decreased winter snowpack and higher maximum summer temperatures. The position of the modern treeline was established by 3000 14 C yr B.P. when Picea retreated downslope in response to Neoglacial cooling.

Ecotones and fluvial regimes in arctic lotic environments

The fluvial regime in arctic streams is influenced by size of stream, the presence and storage capacity of lakes in the drainage basin, groundwater, and permafrost. Exchange of material with terrestrial environments depends on the season and is more or less suspended in winter. Permafrost and water storage in ice and snow control run off and erosion. Damage to vegetation by flooding, fire, animal or human activity can affect the permafrost and result in rapid erosion. Living space and conditions in lotic environments are modified by ice and during break up are very labile. Fish and benthic organisms in streams have behavioural and physiological adaptations which allow them to benefit from the wide range of river and stream environments found in the arctic and to tolerate the range of seasonal conditions. Ecotones are weakly developed in arctic streams and are of minor functional significance. Only farther south does riparian vegetation begin to play a role in regulating stream processes and not until south of the tree line can ecotones be considered important modulators of fluvial environments.

A silicate weathering mechanism linking increases in marine 87Sr/ 86Sr with global glaciation

THE 87Sr/ 86Sr ratio of sea water is generally regarded as a proxy for the rate of chemical weathering of the continents. Interpretation of the 87Sr/86Sr record in marine limestones requires an understanding of how changes in this quantity are linked to climate and tectonic events. A connection between the strontium isotope record and the extent of global glaciation has been proposed1 –8, but without a well established mechanism. Glaciation may influence marine 87Sr/ 86Sr by changing global riverine Sr fluxes (that is, rock weathering rates) and/or 87Sr/86Sr ratios (that is, relative mineral weathering rates). Here we investigate how the 87Sr/86Sr release from silicate weathering is affected by glaciation, using the Sr isotope systematics of granitoid soils on alpine glacial moraines in the Wind River Range, Wyoming. We observe a negative correlation between the 87Sr/86Sr ratio of exchangeable Sr in soils and the soil age, indicating that the 87Sr/86Sr ratio of Sr released in the early stages of weathering is significantly higher than in later stages. We estimate that this mechanism can increase global riverine 87Sr/86Sr by an average of 0.0002 during periods of glacial–interglacial cycling. When superimposed on long-term trends controlled by tectonic processes2–7,9,10, this shift can account for the correlation between the rate of change of marine 87Sr/86Sr and the intensity of glaciation over at least the past 10 Myr.

Soil Evidence for a Glaciation Intermediate between the Bull Lake and Pinedale Glaciations at Fremont Lake, Wind River Range, Wyoming, U.S.A.

Soil Evidence for a Glaciation Intermediate between the Bull Lake and Pinedale Glaciations at Fremont Lake, Wind River Range, Wyoming, U.S.A.

Lead isotope systematics of granitoid weathering

The isotopic composition of lead released by chemical weathering of granitoids was investigated in order to evaluate the sensitivity of this natural tracer as a tool for monitoring mineral weathering and soil development. The isotopic composition of lead was found to change systematically with the relative degree (or maturity) of weathering in both Cretaceous granitoids from the Sierra Nevada batholith (SN) and Precambrian granitoids from the Wind River Range, Wyoming (WRR). In the SN, lead released from crushed bedrock by dilute acid leaching (to simulate the initial stages of weathering) has a composition more radiogenic than observed in soils (average 206Pb 207Pb = 1.335 ). Lead released by leaching from soils developed on a relatively young terrain (~10 kyr old) is less radiogenic (average 206Pb 207Pb = 1.270 ) than crushed bedrock and lead released by leaching from soil developed on older surfaces (~ 100 kyr) is even less radiogenic (average 206Pb 207Pb = 1.255 ). Lead released from the total digestion of the rock has the least radiogenic composition (average 206Pb 207Pb = 1.240 ). In the WRR, systematic changes in the isotopic composition of lead released by leaching were observed in soils developed on glacial moraines of variable ages. Lead released from soil developed on a 21 kyr old moraine was the most radiogenic ( 208Pb 207Pb = 3.257 ). Lead released from soil developed on a 130 kyr old moraine was less radiogenic ( 208Pb 207Pb = 2.780 ) and lead released from soil developed on ≥350 kyr old moraine was the least radiogenic ( 208Pb 207Pb = 2.532 ). The observed systematic changes in the isotopic composition of lead with time in both field areas demonstrates the potential of lead isotopes to ascertain the degree (or maturity) of chemical weathering of granitoids and may have applications in determinations of the relative ages of some glacial deposits.

Modern Pollen Spectra and Vegetation in the Wind River Range, Wyoming, U.S.A.

Modem pollen spectra provide a picture of vegetation communities in the Wind River Range. The broad valleys of western Wyoming, which are covered by big sagebrush steppe, are dominated by Artemisia pollen (averaging 75%) with lesser amounts of Pinus, Tubuliflorae, Gramineae, Chenopodiaceae-Amaranthus, and Ambrosia pollen. The majority of the pollen deposited in the Artemisia steppe comes from local plants. Although all the forests in the Wind River Range are dominated by Pinus contorta-type pollen, each forest type has a unique palynological signature. Populus tremuloides forest stands produce up to 5% Populus pollen. Pseudotsuga menziesii is not widespread in the southern part of the range, and its pollen is most abundant (1%) near where the trees grow. Pinus contortatype pollen (over 80%) dominates Pinus contorta forest stands. Picea and Abies trees in the mixed conifer forest are represented by low, but significant pollen percentages, 3 and 0.5%, respectively. The Pinus albicaulis parkland represents a transitional forest community between the mixed conifer forest and alpine tundra. Palynologically it is indistinct from alpine tundra. While over 50% of the pollen deposited in alpine tundra comes from lower elevations, tundra can be characterized by its relatively high frequency of herbaceous pollen (17%) and significant amounts of Cyperaceae, Gramineae, Tubuliflorae, Salix, and Bistorta pollen from local plants.

Patterns of vegetation and water chemistry in peatlands of the west-central Wind River Range, Wyoming, U.S.A.

Seventeen peatland complexes were investigated in a 2000-ha study area in the Barnes Lake region of the west-central Wind River Range in Wyoming, U.S.A. Sites ranged in elevation from 2970 to 3200 m. The peatlands are generally less than 2 ha in size and are supported by groundwater flow systems. Seventeen plant community types are recognized using two-way indicator species analysis and Braun-Blanquet table methods, including 4 aquatic communities, 6 peatland expanse communities, and 7 peatland margin communities. Surface water in the study area is neutral to slightly acidic with very low cation concentrations. The water pH and flora indicate rich fen conditions, while the cation concentrations are more comparable to poor fens or even bogs. We propose calling the study area peatlands transitional rich fens, which are fed by mineral-poor water. The chemical composition of surface waters was found to be similar among different communities. Patterns of plant species and plant community distribution are a function of the water table depth and duration gradient and flow rates of the water supply. The rich – poor and peatland expanse – peatland margin gradients that reflect nutrient gradients do not appear to be important in the study area. Key words: fens, peatlands, Wyoming, Rocky Mountains, water chemistry, subalpine, alpine.

Mid-Holocene Erosion of Soil Catenas on Moraines near the Type Pinedale Till, Wind River Range, Wyoming

Buried soils are described from the floors of four kettles on Pinedale piedmont moraines of the southwestern Wind River Range, Wyoming, near the type locality of the Pinedale Till. The buried soils indicate that a previously unreported episode of slope erosion has occurred along adjacent catenas on some of the moraines in this region. Radiocarbon ages of the buried soils indicate that slope erosion occurred during the middle Holocene from 8540 ± 190 to 4800 ± 60 14C yr B.P. The presence of buried soils in moraine kettles indicates that profiles on the crests and backslopes of some of the moraines in this region are not the products of continuous post-Pinedale soil formation. Rather, the crest and backslope soils on Pinedale moraines result from two periods of soil development separated by an interval of erosion. Thus, soils on crests and backslopes are considered to be welded profiles. Relative-age studies that use soil data to estimate the age of moraines in this region must take into account the possibility that a mid-Holocene erosion episode affected the genesis and morphology of soils on the moraines. This study corroborates results of previous work that suggests that data from complete catenas are more useful for estimating the characteristic soil development on Quaternary moraines than are data derived from crests alone.

Lithistid sponges from the Late Ordovician Fish Haven Dolomite, Bear River Range, Cache County, Utah

The tricranoclad demosponge Hindia sphaeroidalis Duncan, 1879, is reported as a common silicified sponge in the basal dolomite of the Deep Lakes Member of the Upper Ordovician Fish Haven Formation of northeastern Utah for the first time. A small juvenile orchoclad anthaspidellid, Hudsonospongia? sp., is also the first of that family reported from Fish Haven beds and the Deep Lakes Member. Both taxa are from localities on the eastern slope of Mount Magog, north of Tony Grove Lake, in the Bear River Range, Cache County, east of Logan, Utah.