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Soil relative dating of moraine and outwash-terrace sequences in the northern part of the upper Arkansas Valley, central Colorado, U.S.A. Soil relative dating of moraine and outwash-terrace sequences in the northern part of the upper Arkansas Valley, central Colorado, U.S.A.

Profile development indices for soils developed in moraines and outwash near Twin Lakes and in outwash near Leadville support the correlation of moraines with subdued morphology and two high outwash terraces with the Bull Lake glaciation (ca. 130-160 ka) and the correlation of hummocky moraines and two low outwash terraces with the Pinedale glaciation (ca. 14-47 ka). Elsewhere in the...
Authors
Alan R. Nelson, Ralph R. Shroba

The geochemical record in rock glaciers The geochemical record in rock glaciers

A 9.5 m ice core was extracted from beneath the surficial debris cover of a rock glacier at Galena Creek, northwestern Wyoming. The core contains clean, bubble-rich ice with silty debris layers spaced at roughly 20 cm intervals. The debris layers are similar in appearance to those in typical alpine glaciers, reflecting concentration of debris by melting at the surface during the summer...
Authors
E.J. Steig, J. J. Fitzpatrick, N. Potter, D.H. Clark

Effects of El Nino on streamflow, lake level, and landslide potential Effects of El Nino on streamflow, lake level, and landslide potential

One of the most important sources of year-to-year climate variation in the Southwest is the El Niño phenomenon of the tropical Pacific Ocean. El Niño is a natural but largely unpredictable condition that results from complex interplay among clouds and storms, regional winds, oceanic temperatures, and ocean currents along the equatorial Pacific. Under "normal" conditions, the tropical...
Authors
Richard L. Reynolds, Michael D. Dettinger, Daniel Cayan, Doyle Stephens, Lynn M. Highland, Raymond C. Wilson

Dust deposition downwind of Owens (dry) Lake, 1991–1994: Preliminary findings Dust deposition downwind of Owens (dry) Lake, 1991–1994: Preliminary findings

Salt‐rich dust derived from the Owens Lake playa is deposited in significant quantities to distances of at least 40 km north and south of the playa. Semiannual measurements from 1991 to 1994 of dust deposition rates (dust flux) and composition 2 m above the ground at seven sites in Owens Valley show that (1) dust in Owens Valley is derived mainly from the playa, although areas closer to...
Authors
Marith C. Reheis

Pliocene and early Pleistocene environments and climates of the western Snake River Plain, Idaho Pliocene and early Pleistocene environments and climates of the western Snake River Plain, Idaho

Sedimentological, palynological, and magnetic susceptibility data provide paleoenvironmental and paleoclimatic information from a 989 ft (301 m) core of sediments from the upper Glenns Ferry and Bruneau Formations from near the town of Bruneau in Owyhee County, Idaho. Chronology is based on stratigraphic position, paleomagnetism, and biostratigraphic data, which collectively suggest a...
Authors
Robert S. Thompson

Middle Pliocene vegetation: Reconstructions, paleoclimatic inferences, and boundary conditions for climate modeling Middle Pliocene vegetation: Reconstructions, paleoclimatic inferences, and boundary conditions for climate modeling

The general characteristics of global vegetation during the middle Pliocene warm period can be reconstructed from fossil pollen and plant megafossil data. The largest differences between Pliocene vegetation and that of today occurred at high latitudes in both hemispheres, where warming was pronounced relative to today. In the Northern Hemisphere coniferous forests lived in the modern...
Authors
Robert S. Thompson, R.F. Fleming

Old ice in rock glaciers may provide long-term climate records Old ice in rock glaciers may provide long-term climate records

Anyone who spends much time above the treeline has probably seen rock glaciers and paused to wonder about them. Their curious and occasionally spectacular forms (Figure 1) occur in alpine and polar regions throughout the world, yet much remains uncertain about how they develop. A core of ice recently recovered from a rock glacier in the Absaroka Mountains of northwestern Wyoming vividly
Authors
D.H. Clark, E.J. Steig, N. Potter, J. Fitzpatrick, A.B. Updike, G. M. Clark

Middle Devonian-Mississippian stratigraphy on and near the Nevada Test Site: Implications for hydrocarbon potential Middle Devonian-Mississippian stratigraphy on and near the Nevada Test Site: Implications for hydrocarbon potential

Paleozoic strata on the Nevada Test Site and surrounding area are affected by the intersection of several important geologic trends, including the early Paleozoic rift margin and the Late Devonian-Early Mississippian Antler orogenic foredeep. Upper Paleozoic strata are lithologically diverse and include siliciclastic sediments (carbonaceous shale, clean quartzose sands, bedded chert, and...
Authors
James H. Trexler, James C. Cole, Patricia Cashman
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