Publications

In order to better constrain genetic processes involved in forming mineral deposits (and ultimately exploration models), it helps to know from where the metals of interest are derived. How the metals arrived at their point of deposition, and why they were deposited there, are separate issues. We are using three different techniques in an attempt to better understand these processes for epithermal

No abstract available.

Uplift reconstructions based on the Cape Verde's geological record provide a unique opportunity to study the long-term isostatic movements associated with hotspot activity on a stationary plate environment. The archipelago is considered stationary with respect to its melting source so the hotspot-driven isostatic effects affecting the ocean islands are expected to be enhanced. In this study, Ar–Ar

This database is a compilation of published and some unpublished isotopic and fission track age determinations in central Colorado. The compiled area extends from the southern Wyoming border to the northern New Mexico border and from approximately the longitude of Denver on the east to Gunnison on the west. Data for the tephrochronology of Pleistocene volcanic ash, carbon-14, Pb-alpha, common-lead

The U.S. Geological Survey is required by Congress (under Public Law 86-509) to provide Locatable Mineral Reports to the USDA Forest Service whenever National Forest System lands are sold or exchanged. This volume is a compilation of the reports already provided to the Forest Service by the author in fiscal years 2006-2009 (October 2006-September 2009). Altogether, the reports describe the geology

Sediment-hosted Pb-Zn deposits can be divided into two major subtypes. The first subtype is clastic-dominated lead-zinc (CD Pb-Zn) ores, which are hosted in shale, sandstone, siltstone, or mixed clastic rocks, or occur as carbonate replacement, within a CD sedimentary rock sequence. This subtype includes deposits that have been traditionally referred to as sedimentary exhalative (SEDEX) deposits.

The condensation, evolution, and sublimation of seasonal water and carbon dioxide ices were characterized at the Mars Phoenix landing site from Martian northern midsummer to midspring (Ls ∼ 142° – Ls ∼ 60°) for the year prior to the Phoenix landing on 25 May 2008. Ice relative abundances and grain sizes were estimated using data from the Compact Reconnaissance Imaging Spectrometer for Mars and Hig

Downhole lithologic information and aquifer pumping test data are reported from 464 wells from a broad area of the northern part of the Coast Ranges in California. These data were originally published in paper form as numerous tables within three USGS Water-Supply Papers describing geology and groundwater conditions in Napa and Sonoma Valleys, the Santa Rosa and Petaluma Valley areas, and in the R

Geophysical field investigations have been carried out at the Hidden Dam in Raymond, California for the purpose of better understanding the hydrogeology and seepage-related conditions at the site. Known seepage areas on the northwest right abutment area of the downstream side of the dam are documented by Cedergren. Subsequent to the 1980 seepage study, a drainage blanket with a subdrain system was

Distinguishing discrete population units among continuously distributed coastal small cetaceans is challenging and crucial to conservation. We evaluated the utility of stable isotopes in assessing group membership in bottlenose dolphins (Tursiops truncatus) off west-central Florida by analyzing carbon, nitrogen, and sulfur isotope values (δ13C, δ15N, and δ34S) of tooth collagen from stranded dolph

Natural background levels of Libby-type amphibole in the sediment of the Libby valley in Montana have not, up to this point, been determined. The purpose of this report is to provide the preliminary findings of a study designed by both the U.S. Geological Survey and the U.S. Environmental Protection Agency and performed by the U.S. Geological Survey. The study worked to constrain the natural backg

This report presents summary papers of work conducted between 2002 and 2007 under a 5-year project effort funded by the U.S. Geological Survey Mineral Resources Program, formerly entitled 'Tintina Metallogenic Province: Integrated Studies on Geologic Framework, Mineral Resources, and Environmental Signatures.' As the project progressed, the informal title changed from 'Tintina Metallogenic Provinc