This cover includes locations of alkaline ultramafic igneous rocks. The igneous rocks are evidence for Permian extensional reactivation of the faults of continental rifts in the map area. The igneous rocks are Permian lamprophyres and mica peridotites.

Hildenbrand and Ravat (1997) inferred the locations of near-surface dikes from analyses of high-resolution aeromagnetic data. The lines represent locations of magnetic highs that they interpreted as dikes. Modeling indicates the dikes are vertical, extend

This digital map database was compiled from previously published and unpublished data by the author and USGS colleagues, and from published maps by others, as indicated in figure 3 on the map sheet. A pamphlet included with the map provides a brief discu

This quadrangle lies 6.4 km (4 mi) northeast of Bozeman, Mont., in southwestern Montana. Metamorphic, sedimentary, and volcanic rocks of Precambrian to Tertiary age are exposed in the Bridger Range and southwestern margin of the Crazy Mountains Basin in

The geologic map of the central Marysvale volcanic field, southwestern Utah, shows the geology at 1:100,000 scale of the heart of one of the largest Cenozoic volcanic fields in the Western United States. The map shows the area of 38 degrees 15' to 38 deg

The Eagle quadrangle covers an area that straddles the Eagle River and Interstate 70 (I-70) and it includes the town of Eagle, Colo., which is located in the southwestern part of the quadrangle, just south of I-70 and the Eagle River, about 37 km west of

This digital map database is compiled from unpublished data and new mapping by the authors, represents the general distribution of surficial and bedrock geology in the mapped area. Together with the accompanying pamphlet, it provides current information

This digital map database is compiled from unpublished data and new mapping by the authors, represents the general distribution of surficial and bedrock geology in the mapped area. Together with the accompanying pamphlet, it provides current information

This digital map database is compiled from unpublished data and new mapping by the authors, represents the general distribution of surficial and bedrock geology in the mapped area. Together with the accompanying pamphlet, it provides current information

This digital map database is compiled from unpublished data and new mapping by the authors, represents the general distribution of surficial and bedrock geology in the mapped area. Together with the accompanying pamphlet, it provides current information

This dataset represents geology compiled for the upper Animas River Watershed near Silverton, Colorado. The source data used are derived from 1:24,000, 1:20,000, 1:48,000 and 1:250,000-scale geologic maps by geologists who have worked in this area since

The Rio Puerco quadrangle is located southwest of Albuquerque in central New Mexico and covers part of the western part of the Isleta Reservation. The U.S. Geological Survey, the New Mexico Bureau of Geology and Mineral Resources, and the University of Ne

The Santa Ana Pueblo quadrangle is located in the northern part of the Albuquerque basin, which is the largest basin or graben within the Rio Grande rift. The quadrangle is underlain by poorly consolidated sedimentary rocks of the Santa Fe Group and is d

This digital geologic map compilation presents new polygon (i.e., geologic map unit contacts), line (i.e., fault, fold axis, dike, and caldera wall), and point (i.e., structural attitude) vector data for the Thirsty Canyon NW 7 1/2' quadrangle in southern

This data set maps and describes the geology of the Porcupine Wash 7.5 minute quadrangle, Riverside County, southern California. The quadrangle, situated in Joshua Tree National Park in the eastern Transverse Ranges physiographic and structural province,

This data set maps and describes the geology of the Cucamonga Peak 7.5' quadrangle, San Bernardino County, California. Created using Environmental Systems Research Institute's ARC/INFO software, the database consists of the following items: (1) a map cove

This data set maps and describes the geology of the Pinto Mountain 7.5 minute quadrangle, Riverside County, southern California. The quadrangle, situated in Joshua Tree National Park in the eastern Transverse Ranges physiographic and structural province,

This data set maps and describes the geology of the San Bernardino Wash 7.5 minute quadrangle, Riverside County, southern California. The quadrangle, situated in Joshua Tree National Park in the eastern Transverse Ranges physiographic and structural prov

This data set maps and describes the geology of the Fawnskin 7.5' quadrangle, San Bernardino County, California and contains original U.S. Geological Survey data generated by detailed field observation and by interpretation of aerial photographs. The geo