Geological and borehole geophysical data and observations collected to characterize the basin and its surface and groundwater flow systems with primary focus on the physical characteristics of the fault vein, related mine workings, and surrounding bedrock

Discusses the physical properties of frac sand, its geologic origin and formation contributing processes, its use in industry, consumption history and a global outlook. US / Canadian producers are detailed and potential other sources delineated in a GIS

Mineralogical data on samples from the surface and from drill cores, with geological observations help to understand the hydrology and effects of geology on acid-rock drainage in a mineralized alpine watershed.

Province contains Weka Dur, see companion report chapter B. Reproduces the topology of original Soviet maps and cross sections. Original Russian terminology and rock classification translated into modern English geologic usage as literally as possible.

Presents one of several gold and copper deposit prospect areas in west-central Afghanistan. Reproduced topology of original Soviet maps and cross sections. Original terminology and rock classification translated literally to modern English geologic usage.

Spatial geologic map with rock type, vents, arcs, landslides, etc. provided in an ESRI geodatabase and KMZ format for Google Earth viewing. Mapsheet with accompanying descriptive pamphlet is provided as a PDF. Petrographic rock summary is also included.

The map updates a major geologic map of the Cook Inlet region published in 1976 incorporating new and additional mapping and interpretation. This map is also a revision of areas of overlap with the geologic map completed for central Alaska.

This map depicts the fundamental geologic features for the western part of the Fortymile mining district and delineates the location of known bedrock mineral prospects and their relationship to rock types and structural features.

<h1>Introduction</h1>The San Juan-Silverton caldera complex located near Silverton, Colorado, in the Southern Rocky Mountains volcanic field is an ideal natural laboratory for furthering the understanding of shallow-to-deep volcanic-related mineral system

Geologic map showing the structure and history of the basement rocks of Montana. Most of the state is covered by Phanerozoic bedrock units; the underlying basement structure must be inferred from magnetic anomaly data combined with geologic observations.

A geologic map constructed primarily from reconnaissance studies from the 1950s to 1990s. The rocks of the map area range from Proterozoic age metamorphic rocks of the Kanektok metamorphic complex to Quaternary age mafic volcanic rocks of Nunivak Island.

The Bettles quadrangle includes part of the southern Brooks Range and uplands and valleys of interior Alaska. This map depicts the surficial geology and glacial history, and includes description of map units and a correlation of map units.

This report releases data, cross section, and model information related to the identification of travel paths for groundwater supply and principal stratigraphic and structural features that serve as constraints or conduits for groundwater movement.

Releases airborne survey data, resistivity cross-sections and depth slices derived from data inversion. Resulting resistivity models confirm geologic framework, constrain hydrostratigraphy and depth to basement, and reveal fault and fold distribution.

Identifies hydrothermally altered volcanic edifices and vulnerable areas downstream by mapping alteration on volcanoes, highlighting lahar prone watersheds using Global Digital Elevation Model data, and modeling via a lahar flow-fill modeling program

This study delineated permissive areas for undiscovered porphyry copper deposits, compiled a database of known deposits and significant prospects, estimated undiscovered deposits within those areas and made probabilistic estimates of their metal content.

A multidisciplinary mapping and data integration project focused on long-term resource planning by the mapping and characterization of exposed surface mineralogy, including that related to hydrothermal alteration and supergene weathering of pyritic rocks.

Analysis of mineral and vegetation maps of parts of the Marysvale volcanic field in west-central Utah near the White Horse replacement alunite deposit.

Samples of surficial materials analyzed for aluminum, barium, cadmium, lead, and zinc concentrations.

Flight-line data and gravity grids with documentation.

Mineral groups identified through automated analysis of remote sensing data acquired by the ASTER system were used to map the type and spatial distribution of hydrothermal alteration, other exposed mineral groups, and green vegetation.

This report makes available a large well dataset so that subsurface stratigraphic data are available in digital form for use within a GIS and in construction of three-dimensional models to address regional stratigraphic and structural questions.

This report summarizes the assembly of pertinent data, determination of its limits, analysis of its properties, and the relations among the different data types in preparation for future modeling.

Hydrothermal orebodies and their host rocks are characterized by compositional variations in magnetite. Minor and trace element data for hydrothermal and igneous magnetite are compared with an unmineralized magnetite-series granodiorite in southwest Japan

40Ar/39Ar dating, electron microprobe analyses and geologic mapping help clarify chronology and correlations of the numerous volcanic and intrusive units exposed in the area and interpret the petrogenesis of a few of the volcanic units.

New age determinations with descriptions of sample locations and analytical details.

Presents data for mineral deposits and unaltered and hydrothermally altered volcanic rocks. Data presented were acquired in three USGS labs by three different geochronologists. Analytical methods and data derived from each lab are presented separately.

This map portrays the geodynamics of Northeast Asia at a scale of 1:5,000,000 using the concepts of plate tectonics and analysis of terranes and overlap assemblages.

The region includes a significant part of one of the world’s largest accretionary complexes and a small part of the classic magmatic arc geology of the Alaska Peninsula. The map was compiled from existing mapping augmented by available new or revised data

The Castle Mountain fault is a major east-northeast striking fault in southern Alaska with historic seismicity and Holocene surface faulting. This data set is a compilation of fault segments from several publications.

Regional locations and estimates of the probable amounts of undiscovered resources of copper, platinum-group elements, and potash in selected types of mineral deposits to depths of 1 to 3 kilometers below the surface of the earth worldwide.

Provides a view of alluvial basins, shapes, areal extents, and approximate thicknesses of alluvial fill. Gravity field is separated into density variations in the basement complex and distribution of Cenozoic fill with its 3-D thickness representation.

Maps and data showing the geographic distribution of surficial minerals likely produced by hydrothermal alteration, which may indicate areas permissive of gold and copper mineral deposits.

Data represent work completed when the study ended due to lack of funding. Geologic and site information on each specific deposit or occurrence are provided. Analytical and geologic data are summarized and site descriptions for samples analyzed are listed

Chemical analysis of 201 samples of rocks thought to be altered or mineralized in an area containing numerous mines.

This map covers the Eagle 1:250,000-scale quadrangle in the northeastern part of the Yukon-Tanana Upland in Alaska. It shows the extent of five major glacial advances, former glacial lakes, and present fragmented terrace deposits related to the advances.

This 1:100,000-scale digital geologic map details the complex early Proterozoic granitic rocks, early Proterozoic supracrustal metamorphic rocks, and Archean crystalline basement of the Black Hills.

Maps and data showing the geographic distribution of surficial minerals likely produced by hydrothermal alteration, which may indicate areas permissive of gold and copper mineral deposits.

Study delineated permissive areas for undiscovered porphyry copper deposits, compiled a database of known deposits and significant prospects, estimated undiscovered deposits within those areas and made probabilistic estimates of their metal content.

This study delineated permissive areas for undiscovered porphyry copper deposits, compiled a database of known deposits and significant prospects, estimated undiscovered deposits within those areas and made probabilistic estimates of their metal content.

Delineated permissive areas for undiscovered porphyry copper deposits, compiled a database of known deposits and significant prospects, estimated undiscovered deposits within those areas and made probabilistic estimates of their metal content.

This study delineated permissive areas for undiscovered porphyry copper deposits, compiled a database of known deposits and significant prospects, estimated undiscovered deposits within those areas and made probabilistic estimates of their metal content

This study delineated permissive areas for undiscovered porphyry copper deposits, compiled a database of known deposits and significant prospects, estimated undiscovered deposits within those areas and made probabilistic estimates of their metal content.

This study delineated permissive areas for undiscovered porphyry copper deposits, compiled a database of known deposits and significant prospects, estimated undiscovered deposits within those areas and made probabilistic estimates of their metal content.

This study delineated permissive areas for undiscovered porphyry copper deposits, compiled a database of known deposits and significant prospects, estimated undiscovered deposits within those areas and made probabilistic estimates of their metal content.

This study delineated permissive areas for undiscovered porphyry copper deposits, compiled a database of known deposits and significant prospects, estimated undiscovered deposits within those areas and made probabilistic estimates of their metal content.

Regional maps of phyllic and argillic hydrothermal alteration are presented on 10 separate plates available in either low or high resolution. A GIS package includes points features for potential porphyry copper sites also provided in tabular form.

This report describes key features; identifies tectonic-sedimentary environments; illustrates geochemical, geophysical, and geoenvironmental characteristics; evaluates deposit formation; presents exploration and assessment guides; and lists knowledge gaps

This report is a compilation of water and sediment chemical data generated by the USGS study of indigenous, arsenic-sequestering microbial communities. A total of 9 synoptic sampling efforts conducted at specific sites are described.

Investigates Cr and Ni geochemistry providing insight into the mobility and bioaccessibility of these toxic trace elements throughout northern California and perhaps the origin of elevated dissolved Cr(VI) concentrations in the western Sacramento Valley