Publications

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 trade winds bl

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 the sites

No abstract available.

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 illustrate

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 chert-lit

No abstract available.

The paleoclimatic history of western Utah is being investigated as part of the USGS Global Change and Climate History Program studies of long-term climatic changes in the western United States. The initial objective of the study is to document the environmental conditions during the mid-Pliocene period of warmer-than-modern global climates (the focus of the USGS Pliocene Research, Interpretation,

Dust samples collected annually for 5 years from 55 sites in southern Nevada and California provide the first regional source of information on modern rates of dust deposition, grain size, and mineralogical and chemical composition relative to climate and to type and lithology of dust source. The average silt and clay flux (rate of deposition) in southern Nevada and southeastern California ranges

Stable oxygen and carbon isotope geochemistry of ostracode valves, abundance and assemblages of ostracode species, and sedimentological parameters from cores taken in Williams and Shingobee Lakes in north-central Minnesota show changes in climatic and hydrologic history during the Holocene. Isotopic records are consistent with the following scenario:Before 9800 yr B.P. the two lakes were connected

During the Pinedale (Late Wisconsinan) glaciation, an outlet glacier from a mountain ice field flowed eastward across the Continental Divide through Marias Pass in northwestern Montana. This outlet glacier was the major source of the Two Medicine glacier, a large piedmont glacier that extended from the mountain front east about 55 km onto the plains. An accelerator mass spectrometry radiocarbon ag

Estimates of the epicentral location and maximum intensity of the earthquake of 14 December 1872, the largest and oldest historic earthquake documented in the Pacific Northwest, are controversial largely because the estimates are based on ground effects. The Ribbon Cliff landslide is one of the more critical ground effects used to argue that the epicenter was in the vicinity of Lake Chelan in cent

Eolian sediment covers about 60% of Colorado east of the Rocky Mountains; about 30% of the sediment is sand and 70% is loess. Initially, flood plains were the principal sources of eolian sediment, but during the Holocene, dunes formed from older eolian sand and alluvium on uplands. Since latest Pleistocene time, dominant dune-forming winds have been northwesterly in the northern part of the region