Map Releases

This digital map database, compiled from previously published and unpublished data, and new mapping by the authors, represents the general distribution of bedrock and surficial deposits of the Silver lake 7.5 minute quadrangle. The database delineates map units that are identified by general age and lithology following the stratigraphic nomenclature of the U.S. Geological Survey. The...

No abstract available.

The geology of the Thaumasia region (fig. 1, sheet 3) includes a wide array of rock materials, depositional and erosional landforms, and tectonic structures. The region is dominated by the Thaumasia plateau, which includes central high lava plains ringed by highly deformed highlands; the plateau may comprise the ancestral center of Tharsis tectonism (Frey, 1979; Plescia and Saunders...

This digital map database was compiled from previously published and unpublished data by the author and USGS colleagues, and from published maps by others, as indicated in figure 3 on the map sheet.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 discussion of the geology of the quadrangle, a description of map units, and references cited.

The bedrock exposed in the Winona Quadrangle, Missouri, comprises Mesoproterozoic aged volcanic rocks overlain by Late Cambrian and Early Ordovician aged dolomite, sandstone, and chert. The sedimentary rocks are nearly flat-lying except where they drape around knobs of the volcanic rocks or where they are adjacent to faults. The carbonates are karstified and the area contains numerous...

This geologic mapping and interpretation of the Pea Ridge iron mine, Missouri, is part of a cooperative effort between the U.S. Geological Survey (USGS) and the Missouri Department of Natural Resources, Division of Geology and Land Survey (DGLS), under the auspices of the USGS Midcontinent Strategic and Critical Minerals Project. The goal of the Pea Ridge study is to compare the Middle...

This digital map database, compiled from previously published and unpublished data, and new mapping by the authors, represents the general distribution of bedrock and surficial deposits in the mapped area. Together with the accompanying text file (scvmf.ps, scvmf.pdf, scvmf.txt), it provides current information on the geologic structure and stratigraphy of the area covered. The database

Ganymede is the largest (~5,200 km diameter) of the Jovian satellites. Surficial features on Ganymede, as recorded by the Voyager 1 and 2 spacecraft (Smith and others, 1979a; 1979b), indicate a complex history of crustal formation. Several episodes of crustal modification led to the formation of curvilinear systems of furrows in dark terrain, the emplacement of light materials, and the...

No abstract available.

No abstract available.

This report presents a network of 28 geologic cross sections that portray subsurface geologic relations within the Death Valley regional ground-water system, a ground-water basin that encompasses a 3? x 3? area (approximately 70,000 km2) in southern Nevada and eastern California. The cross sections transect that part of the southern Great Basin that includes Death Valley, the Nevada Test...

An isostatic gravity map of the Death Valley groundwater model area was prepared from over 40,0000 gravity stations as part of an interagency effort by the U.S. Geological Survey and the U.S. Department of Energy to help characterize the geology and hydrology of southwest Nevada and parts of California.