Petrographic and geochemical analyses of 50 outcrop samples and 58 drill core samples.

Compilation of all available chemical data (more than 2,000 samples) for igneous rocks that constitute the southern segment of the ancestral Cascades magmatic arc.

Geochemical analyses of Cretaceous igneous intrusions in order to establish the geologic framework for world-class mineral deposits of the Butte district

Geochemical and mineralogical analyses of plutonic rock samples

The purpose of this report is to present available petrographic and geochemical data for unmineralized rock samples, principally volcanic rocks and to make those data available to ongoing petrogenetic investigations of these rocks.

<p>The purposes of this report are to (1) present available geochemical and modal data for igneous rocks associated with epithermal mineral deposits and (2) to make those data widely and readily available for subsequent, more in-depth consideration and in

The Paleocene Fort Union Formation hosts a compositionally diverse array of Eocene plugs, dikes, and sills arrayed around the Eocene Big Timber stock in the Crazy Mountains of south-central Montana. The geochemistry and petrography of the sills have no

This report presents and makes data available to ongoing petrogenetic investigations of these rocks. It develops an accurate and current portrayal of their spatial distribution in GIS format while analyzed samples are presented via Excel workbooks.

<p id="sp0090">Newly synthesized data indicate that the geochemistry of igneous rocks associated with epithermal mineral deposits varies extensively and continuously from subalkaline basaltic to rhyolitic compositions. Trace element and isotopic data for

The conterminous United States hosts numerous volumetrically significant and geographically dispersed granitoid intrusions that range in age from 1.50 to 1.32 billion years before present (Ga). Although previously referred to as A-type granites, most are

Geochemical, petrographic, and geochronologic data for samples, principally those of unmineralized Tertiary volcanic rocks, from the Tonopah, Divide, and Goldfield mining districts of west-central Nevada.

Miocene calc-alkaline volcanic rocks, part of the southern segment of the ancestral Cascades magmatic arc, are spatially, temporally, and likely genetically associated with precious metal epithermal deposits in the Tonopah, Divide, and Goldfield Districts

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.

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.

Sample description, location, and geochemical analysis of Mesoproterozoic igneous rocks and iron oxide-apatite-rare earth element and iron oxide-copper-cobalt-gold deposits in this area. Data are provided in Microsoft Access and tab-delimited text formats.

A compilation of new and previously published geochemical and modal analyses of Mesoproterozoic igneous rocks in this area. Includes major and trace element geochemistry and mineralogical composition as well as sample locations and characteristics. Data for 618 unaltered samples and 549 altered samples are provided as Microsoft Excel and as tab-delimited text.

<div>The Bodie Hills is a ~40 by ~30 kilometer volcanic field that straddles the California-Nevada state boundary between Mono Lake and the East Walker River. Three precious metal mining districts and nine alteration zones are delineated in Tertiary-Quate

Epithermal gold-silver deposits are vein, stockwork, disseminated, and replacement deposits that are mined primarily for their gold and silver contents; some deposits also contain substantial resources of lead, zinc, copper, and (or) mercury. These deposi

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.