Publications

The Apache Canyon 7.5-minute quadrangle is located in southwestern California about 55 km northeast of Santa Barbara and 65 km southwest of Bakersfield. This report presents the results of a geologic mapping investigation of the Apache Canyon quadrangle that was carried out in 1997-1999 as part of the U.S. Geological Survey's Southern California Areal Mapping Project. This quadrangle was chosen fo

Between 1961 and 1969, Alan Griggs and others conducted fieldwork to prepare a geologic map of the Spokane 1:250,000 map (Griggs, 1973). Their field observations were posted on paper copies of 15-minute quadrangle maps. In 1999, the USGS contracted with the Idaho Geological Survey to prepare a digital version of the Coeur d’Alene 1:100,000 quadrangle. To facilitate this work, the USGS obtained the

This report contains information about the composition of interstitial porewater and solids from water saturated, metal contaminated levee banks at the river's edge and marshes in the lower Coeur d'Alene River valley. Data include pH, alkalinity, and concentrations of sulfate and metals (arsenic [As], cadmium [Cd], copper [Cu], iron [Fe], mercury [Hg], manganese [Mn], lead [Pb], antimony [Sb], and

Coccidioidomycosis (Valley Fever) is a disease caused by the inhalation of the arthroconidia (spores) of Coccidioides immitis, a fungus that lives in the soils of southwestern United States. Although large numbers of people are exposed to the arthroconidia and are consequently infected, very few individuals contract the more serious forms of the disease. Earth scientists working in field areas whe

Gravity data were used to study the basement structure of Langford Well Lake basin at the U.S. Army National Training Center, Fort Irwin, California. Figure 1 shows the location of the study area. During 1996 and 1999, 290 new gravity stations were measured. These data were merged with existing data to produce a depth-to-basement map, which, in turn was converted to a structure map of the basement

In April 2000 the U.S. Geological Survey (USGS) established 211 gravity stations in the Antelope Valley and Bedell Flat area of west-central Nevada (see figure 1). The stations were located about 15 miles north of Reno, Nevada, southwest of Dogskin Mountain, and east of Petersen Mountain, concentrated in Antelope Valley and Bedell Flat (figure 2). The ranges in this area primarily consist of norma

An aeromagnetic map of the Nevada Test Site area was prepared from publicly available aeromagnetic data described by McCafferty and Grauch (1997). Magnetic surveys were processed using standard techniques. Southwest Nevada is characterized by magnetic anomalies that reflect the distribution of thick sequences of volcanic rocks, magnetic sedimentary rocks, and the occurrence of granitic rocks. In a

An isostatic gravity map of the Nevada Test Site area was prepared from publicly available gravity data (Ponce, 1997) and from gravity data recently collected by the U.S. Geological Survey (Mankinen and others, 1999; Morin and Blakely, 1999). Gravity data were processed using standard gravity data reduction techniques. Southwest Nevada is characterized by gravity anomalies that reflect the distri

This geologic map database for the El Mirage Lake area describes geologic materials for the dry lake, parts of the adjacent Shadow Mountains and Adobe Mountain, and much of the piedmont extending south from the lake upward toward the San Gabriel Mountains. This area lies within the western Mojave Desert of San Bernardino and Los Angeles Counties, southeastern California. The area is traversed by a

Turcotte, 1997, and Barton and La Pointe, 1995, have identified many potential uses for the fractal dimension in physicochemical models of surface properties. The image-analysis program described in this report is an extension of the program set MORPH-I (Mossotti and others, 1998), which provided the fractal analysis of electron-microscope images of pore profiles (Mossotti and Eldeeb, 1992). MORPH

This report summarizes the acquisition, data processing, and preliminary interpretation of a high-resolution aeromagnetic and radiometric survey near the confluence of the Big and Little Chino basins in the headwaters of the Verde River, Arizona. The goal of the aeromagnetic study is to improve understanding of the geologic framework as it affects groundwater flow, particularly in relation to the

A high-resolution aeromagnetic survey of the Amargosa Desert and surrounding areas provides insights into the buried geology of this structurally complex region. The survey covers an area of approximately 7,700 km2 (2,970 mi2), extending from Beatty, Nevada, to south of Shoshone, California, and includes parts of the Nevada Test Site and Death Valley National Park. Aeromagnetic flight lines were o