Publications

Dense populations of the coccolithophore Pleurochrysis pseudoroscoffensis were found in surface films at several locations around the Salton Sea in February–August, 1999. An unidentified coccolithophorid was also found in low densities in earlier studies of the lake (1955–1956). To our knowledge, this is the first record of this widespread marine species in any lake. Samples taken from surface fil

Land subsidence associated with ground-water-level declines has been recognized as a potential problem in Coachella Valley, California. Since the early 1920s, ground water has been a major source of agricultural, municipal, and domestic supply in the valley, resulting in water-level declines as large as 15 meters (50 feet) through the late 1940s. In 1949, the importation of Colorado River water to

In 1996-1998 the U.S. Geological Survey (USGS) conducted a geochemical study of the Bureau of Land Management's (BLM) 5.5 million-acre Northern and Eastern Colorado Desert Resource Area (usually referred to as the NECD in this report), Imperial, Riverside, and San Bernardino Counties, southeastern California (figure 1). This study was done in support of the BLM's Coordinated Management Plan for th

The Salton Sea is an ecosystem in peril. Its prehistory consists of a series of intermittent lakes dependent on infrequent flooding of the Colorado River, while the modern Salton Sea originated from the desire to harness the flow of the Colorado River for irrigation. What began as an accident of this attempt is now a permanent inland sea supported by wastewater and agricultural drainage rather tha

No abstract available at this time

Microfossiliferous marine sediments of the Imperial Formation exposed in the Whitewater and Cabazon areas, near San Gorgonio Pass, southern California, are late Miocene in age and were deposited at intertidal to outer neritic depths, and possibly upper bathyal depths. A late Miocene age of 7.4 to >6.04 Ma is based on the ranges of age-diagnostic benthic foraminifers (Cassidulina delicata and Uvige

Prey items were identified from the stomachs of wintering Mountain Plovers (Charadrius montanus) collected in California at the Pixley National Wildlife Refuge and Carrizo Plain Natural Area in 1991, and south of the Salton Sea in 1992. Stomach contents of the 39 birds included 2,092 different food items representing 13 orders and at least 16 families of invertebrates. Diets at each of the three l

No abstract available at this time

Adult eared grebes exhibit threefold fluctuation in body mass and up to a fivefold variation in liver weight during the course of their annual breeding and migratory cycle. Concentrations of 20 metals or metalloids were quantified in the liver from eared grebes obtained at three phases of their annual cycle: newly arrived migrants (July-August-September), staging (October-November), and immediate

The upper Miocene to Pliocene Bouse Formation in the lower Colorado River trough, which consists largely of siltstone with basal tufa and marl, has been interpreted as estuarine on the basis of paleontology. This interpretation requires abrupt marine inundation that has been linked to early rifting in the Gulf of California and Salton trough. New strontium isotope measurements reported here from c

This paper presents data and modelling results from a crustal and upper mantle wide-angle seismic transect across the Salton Trough region in southeast California. The Salton Trough is a unique part of the Basin and Range province where mid-ocean ridge/transform spreading in the Gulf of California has evolved northward into the continent. In 1992, the U.S. Geological Survey (USGS) conducted the fi

Results of a detailed study by the National Irrigation Water-Quality Program (NIWQP), U.S. Department of the Interior, indicate that factors controlling contaminant concentrations in subsurface irrigation drainwater in the Imperial Valley are soil characteristics, hydrology, and agricultural practices. Higher contaminant concentrations commonly were associated with clayey soils, which retard the m