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Keith Robinson

Publications and source records attributed to Keith Robinson.

At least 19 recordsLinked to original sources
USGS2012

MERGANSER: an empirical model to predict fish and loon mercury in New England lakes

MERGANSER (MERcury Geo-spatial AssessmeNtS for the New England Region) is an empirical least-squares multiple regression model using mercury (Hg) deposition and readily obtainable lake and watershed features to predict fish (fillet) and common loon (blood) Hg in New England lakes. We modeled lakes larger than 8 ha (4404 lakes), using 3470 fish (12 species) and 253 loon Hg concentrations from 420 lakes. MERGANSER predictor variables included Hg deposition, watershed alkalinity, percent wetlands, percent forest canopy, percent agriculture, drainage area, population density, mean annual air temperature, and watershed slope. The model returns fish or loon Hg for user-entered species and fish length. MERGANSER explained 63% of the variance in fish and loon Hg concentrations. MERGANSER predicted that 32-cm smallmouth bass had a median Hg concentration of 0.53 μg g -1 (root-mean-square error 0.27 μg g -1 ) and exceeded EPA's recommended fish Hg criterion of 0.3 μg g -1 in 90% of New England lakes. Common loon had a median Hg concentration of 1.07 μg g -1 and was in the moderate or higher risk category of >1 μg g -1 Hg in 58% of New England lakes. MERGANSER can be applied to target fish advisories to specific unmonitored lakes, and for scenario evaluation, such as the effect of changes in Hg deposition, land use, or warmer climate on fish and loon mercury.

New England↗
USGS1982

Geochemical reconnaissance for uranium occurrences in the Notch Peak intrusive area, House Range, Millard County, Utah

Samples collected from the contact metamorphic zone of the Notch Peak intrusive area, House Range, Millard County, Utah, indicate the occurrence of low-grade uranium and thorium ore. Maximum abundances in the altered mineralized rocks in the contact zone are 450 ppm uranium and 480 ppm thorium. Interpretation of factor analysis of the spectrochemical and delayed neutron analytical data suggests the presence of five geological factors which account for 82 percent of element covariance of 34 elements in 61 samples. The factors are identified as (1) limestone source rock reactions; (2) monzonite source rock reactions; (3) hydrothermal element group 1; (4) rare earth group; and (5) hydrothermal element group 2. The last factor effects the distribution of, primarily, beryllium, uranium, copper, molybdenum, tungsten, niobium, and secondarily, thorium, tin, and zinc; it is identified as the prime mineralization factor. The Notch Peak intrusive area has been a tungsten producing area since before the 1940's and the location of small-scale gold placer operations. This reconnaissance study was a 'follow-up' of uranium anomaly data which were developed during the U.S. Dept. of Energy National Uranium Resource Evaluation (NURE) program in 1978-80.

Open-File Report↗
USGS1977

The Alaskan Mineral Resource Assessment Program; background information to accompany folio of geologic and mineral resource maps of the McCarthy Quadrangle, Alaska

The McCarthy 1? by 3? quadrangle, in eastern south-central Alaska, contains potentially significant resources of copper and possibly of a few other commodities. This circular and a companion folio of maps represent results of integrated field and laboratory studies in the disciplines of geology, geophysics, geochemistry, and satellite imagery that are designed to provide a modern mineral resource assessment of the quadrangle. The maps are accompanied by descriptive texts, explanatory material, pertinent references, and by a few auxiliary tables and diagrams. This circular provides background information for the mineral resource assessment and integrates the component maps. It also includes a master list of references (see 'Bibliography') relevant to the geology and mineral deposits of the quadrangle.

Circular↗
USGS1976

Distribution and abundance of copper in stream sediments and moraine debris, McCarthy Quadrangle, Alaska

A geochemical survey was conducted in the McCarthy quadrangle, Alaska, to identify areas containing anomalous concentrations of various metallic and nonmetallic elements. This study incorporates the results of analyses for copper, from 1,454 stream sediment and glacial moraine debris samples collected in the quadrangle, and analyzed by the U.S. Geological Survey between 1961 and 1976 using semiquantitative emission spectrophotometry. In addition, the study includes most of the analytical results of the samples of stream sediment from the White River area, located in the northwestern part of the quadrangle, which were collected and analyzed by the Alaska Division of Mines and Geology (Knaebel, 1971).

Alaska↗
USGS1976

Distribution and abundance of lead in stream sediments and moraine debris, McCarthy Quadrangle, Alaska

A geochemical survey was conducted in the McCarthy quadrangle, Alaska, to identify areas containing anomalous concentrations of various metallic and nonmetallic elements. This study incorporates the results of analyses for lead, from 1,453 stream sediment and glacial moraine debris samples collected in the quadrangle, and analyzed by the U.S. Geological Survey between 1961 and 1976 using semiquantitative emission spectrophotometry. In addition, the study includes most of the analytical results of the samples of stream sediment from the White River area, located in the northwestern part of the quadrangle, which were collected and analyzed by the Alaska Division of Mines and Geology (Knaebel, 1971).

Alaska↗
USGS1976

Distribution and abundance of gold in stream sediments and moraine debris, McCarthy quadrangle, Alaska

A geochemical survey was conducted in the McCarthy quadrangle Alaska, to identify areas containing anomalous concentrations of various metallic and nonmetallic elements. This study incorporates the results of analyses for gold from 764 stream sediment and glacial moraine debris samples collected in the quadrangle, and analyzed by the U.S. Geological Survey between 1961 and 1976 using atomic absorption spectrophotometry. No analytical results for gold are available for stream sediment samples from the White River area, located in the northeastern part of the quadrangle. The accompanying map shows the distribution and relative abundance of gold in stream sediment and glacial moraine debris samples. Geochemical analyses have been grouped and are represented by symbols on a base map, which includes topography and generalized geology. The range of analytical values and the symbol that represents it are shown on the histogram. Graphical representation of analytical values on the map permits easy observation of any large variation resulting from separate or duplicate samples collected at the same or nearby localites.

Alaska↗