Publications

Due to water resources of portions of the North Platte River basin being designated as over-appropriated by the State of Nebraska Department of Natural Resources (DNR), the North Platte Natural Resources District (NPNRD), in cooperation with the DNR, is developing an Integrated Management Plan (IMP) for groundwater and surface water in the NPNRD. As part of the IMP, a three-dimensional...

In May 2006, the U.S. Geological Survey, in cooperation with the U.S. Army Corps of Engineers, conducted surface and borehole geophysical surveys at the former Tyson Valley Powder Farm near Eureka, Mo., to identify preferential pathways for potential contaminant transport along the bedrock surface and into dissolution-enhanced fractures. The Tyson Valley Powder Farm was formerly used as...

The Brooks Range contains enormous accumulations of zinc and copper, either as VMS or sediment-hosted deposits. The Ruby Creek and Omar deposits are Cu-Co stratabound deposits associated with dolomitic breccias. Numerous volcanogenic Cu-Zn (+/-Ag, Au) deposits are situated ~20 km north of the Ruby Creek deposit. The carbonate-hosted deposits consist of chalcopyrite and bornite that fill...

The composition and Cl/Br – NaCl ratios of highly saline aqueous inclusions from large tonnage (> 100 t) IOCG deposits (Sossego, Alvo 118, and Igarapé Bahia) and a Paleoproterozoic intrusion-related Cu-Au-(Mo-W-Bi-Sn) deposit (Breves; 50 Mt)) in the Carajás Mineral Province have been analysed by LA-ICP-MS and ion chromatography. In both Cu-Au systems, brine inclusions are Ca-dominated (5...

Microchemical characterisation of bedrock and placer gold grains from six gold districts within the Archaean domains and intervening Neoproterozoic Anaboriana-Manampotsy belt of northern and east-central Madagascar show few opaque inclusions (e.g pyrrhotite, Bi tellurides) but wide range of Ag contents (40wt%). Some districts exhibit multiple source populations of grains. The...

An in-situ LA-ICP-MS study of different generations of uraninite from the Mesoarchaean Witwatersrand gold palaeoplacer deposits revealed unusually high Au concentrations in rounded, detrital uraninite grains but no detectable Au in secondary, hydrothermally mobilised uraninite. A Au-enriched uraninite-bearing magmatic host is suggested as a significant source for detrital gold in the...

High-resolution aeromagnetic data were acquired over the town of Poncha Springs and areas to the northwest to image faults, especially where they are concealed. Because this area has known hot springs, faults or fault intersections at depth can provide pathways for upward migration of geothermal fluids or concentrate fracturing that enhances permeability. Thus, mapping concealed faults...

This Open-File Report was originally an Administrative Report presentation to the Bureau of Indian Affairs based on U.S. Geological Survey data that has been collected and presented in four previous reports (Open-File Reports 2009-1020, 2008-1380, and 2008-1374, and an Administrative Report on geophysical data). This presentation was given at a technical meeting requested by the BIA on...

This report presents all petrographic, major oxide, and trace element data for a set of 109 samples collected during an investigation of Jurassic igneous rocks in the Bald Mountain mining district, Nevada. Igneous rocks in the district include the Bald Mountain stock, quartz-feldspar porphyry dikes, basaltic andesite dikes, aplite sills, and rare lamprophyre dikes. These rocks, although...

This report presents and compares mineral and vegetation maps of parts of the Marysvale volcanic field in west-central Utah that were published in a recent paper describing the White Horse replacement alunite deposit. Detailed, field-verified maps of the deposit were produced from Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) data acquired from a low-altitude Twin Otter...

This presentation covers three general topics: (1) description of a new geologic compilation of the United States that shows the location of magnesium-rich ultramafic rocks in the conterminous United States; (2) conceptual illustration of the potential ways that ultramafic rocks could be used to sequester carbon dioxide; and (3) description of ways to use geophysical data to refine and...

Gravity and aeromagnetic data provide the underpinnings of a hydrogeologic framework for the Mojave National Preserve by estimating the thickness of Cenozoic deposits and locating inferred structural features that influence groundwater flow. An inversion of gravity data indicates that thin (