Skip to main content

Carma A. San Juan

thumbnail
The polygon (vector) feature class represents locatable mineral resource assessment tracts (tracts of land) associated with the Department of the Interior (DOI) Sagebrush Focal Areas (SFAs) in Montana, Wyoming and Utah, central Idaho, and the Oregon-Nevada-Idaho border area. The mineral-resources tracts are geographic areas that were assessed by the USGS and were determined to be geologically favorable for a deposit type of interest to a depth of 1 kilometer. Qualitative assessment methods outlined by the Bureau of Land Management (BLM) were used to develop tract boundaries and to assign a level of mineral-resource potential and certainty to each tract. The general process included (1) identifying possible mineral...
Categories: Publication; Types: Citation
thumbnail
The polygon (vector) shapefile represents Public Land Survey System (PLSS) sections, or 1-square mile areas of land, with information about Bureau of Land Management (BLM) land and mineral use authorizations for mining claims. For each section, the number of claims (by type) was determined and a density (by claim type) was calculated. The land areas specified by BLM authorizations vary in size and orientation, and may cross PLSS section boundaries. For spatial consistency, the information was aggregated to the square mile PLSS section boundary. The original source data from BLM Cases Recordation database (LR2000) were specific to the day they were generated (March 6, 2016) and subsequent data pulls will likely be...
thumbnail
In conjunction with the future planning needs of the U.S. Department of Agriculture, Forest Service, the U.S. Geological Survey conducted a detailed environmental assessment of the effects of historical mining on Forest Service lands in central Colorado. Stream sediment, macroinvertebrate, and various filtered and unfiltered water quality samples were collected during low-flow over a four-year period from 2004–2007. This report summarizes the sampling strategy, data collection, and analyses performed on these samples. The data are presented in Geographic Information System, Microsoft Excel, and comma-delimited formats. Reports on data interpretation are being prepared separately.
Categories: Publication; Types: Citation; Tags: Data Series
thumbnail
The purpose of this report is to present available geochemical, modal, and geochronologic data for approximately 1.4 billion year (Ga) A-type granitoid intrusions of the United States and to make those data available to ongoing petrogenetic investigations of these rocks. A-type granites, as originally defined by Loiselle and Wones (1979), are iron-enriched granitoids (synonymous with the ferroan granitoids of Frost and Frost, 2011) that occur in an anorogenic, within-continent setting. Relative to other granitic rocks, A-type granites have high FeO*/(FeO*+MgO), high K2O and K2O/Na2O, are metaluminous to weakly peraluminous, and are enriched in incompatible trace elements. Loiselle and Wones (1979) further suggested...
Categories: Publication; Types: Citation; Tags: Data Series
thumbnail
Whole body Zn concentrations in individuals (n = 825) from three aquatic insect taxa (mayflies Rhithrogena spp. and Drunella spp. and the caddisfly Arctopsyche grandis) were used to predict effects on populations and communities (n = 149 samples). Both mayflies accumulated significantly more Zn than the caddisfly. The presence/absence of Drunella spp. most reliably distinguished sites with low and high Zn concentrations; however, population densities of mayflies were more sensitive to increases in accumulated Zn. Critical tissue residues (634 (mu or u)g/g Zn for Drunella spp. and 267 (mu or u)g/g Zn for Rhithrogena spp.) caused a 20% reduction in maximum (90th quantile) mayfly densities. These critical tissue residues...
View more...
ScienceBase brings together the best information it can find about USGS researchers and offices to show connections to publications, projects, and data. We are still working to improve this process and information is by no means complete. If you don't see everything you know is associated with you, a colleague, or your office, please be patient while we work to connect the dots. Feel free to contact sciencebase@usgs.gov.