Geology topics
M.A. Chaffee
Publications and source records attributed to M.A. Chaffee.
Maps showing distribution of iron, cobalt, barium, strontium, arsenic, antimony, and bismuth in samples of minus-60-mesh (0.25-MM) stream sediment and (or) nonmagnetic heavy-mineral concentrate, Walker Lake 1 degree by 2 degrees Quadrangle, California and Nevada
This report is part of a folio of maps of the Walker Lake 1 o x 2 o quadrangle, California and Nevada, prepared under the Conterminous United States Mineral Assessment Program. The folio includes geological, geochemical, and geophysical maps, as well as mineral resources assessment maps, which identify selected known or possible mineral-deposit environments in the quadrangle. The geochemical maps show the distributions of selected individual elements (Chaffee and others, 1988 a, b, c) and the distributions of selected groups of elements (Chaffee, 1988a, b, c). Discussions accompanying the individual element maps are restricted to mineral residences of the individual elements as well as to what types of mineral deposits and environments may be represented by anomalies of a particular element. Discussions accompanying the multielemental maps describe the types of mineral deposits that may be related to each element group and indicate the most favorable localities for these deposits.
Maps showing distribution of anomalies based on the use of R-mode factor analysis for selected groupings of elements in samples of minus-60-mesh (0.25-MM) stream sediment and nonmagnetic heavy-mineral concentrate, Walker Lake 1 degree by 2 degrees Quadrangle, California and Nevada
This report is part of a folio of maps of the Walker Lake 1 o x 2 o quadrangle, California and Nevada, prepared under the Conterminous United States Mineral Assessment Program. The folio includes geological, geochemical, and geophysical maps, as well as mineral resources assessment maps, which identify selected known or possible mineral-deposit environments in the quadrangle. The geochemical maps show the distributions of selected individual elements (Chaffee and others, 1988 a, b, c) and the distributions of selected groups of elements (Chaffee, 1988a, b, c). Discussions accompanying the individual element maps are restricted to mineral residences of the individual elements as well as to what types of mineral deposits and environments may be represented by anomalies of a particular element. Discussions accompanying the multielemental maps describe the types of mineral deposits that may be related to each element group and indicate the most favorable localities for these deposits.
Maps showing distribution of anomalies based on the use of scoresum plots for selected groupings of elements in samples of minus-60-mesh (0.25-MM) stream sediment, Walker Lake 1 degree by 2 degrees Quadrangle, California and Nevada
This report is part of a folio of maps of the Walker Lake 1 o x 2 o quadrangle, California and Nevada, prepared under the Conterminous United States Mineral Assessment Program. The folio includes geological, geochemical, and geophysical maps, as well as mineral resources assessment maps, which identify selected known or possible mineral-deposit environments in the quadrangle. The geochemical maps show the distributions of selected individual elements (Chaffee and others, 1988 a, b, c) and the distributions of selected groups of elements (Chaffee, 1988a, b, c). Discussions accompanying the individual element maps are restricted to mineral residences of the individual elements as well as to what types of mineral deposits and environments may be represented by anomalies of a particular element. Discussions accompanying the multielemental maps describe the types of mineral deposits that may be related to each element group and indicate the most favorable localities for these deposits.
Maps showing distribution of anomalies based on the use of scoresum plots for selected groupings of elements in samples of nonmagnetic heavy-mineral concentrate, Walker Lake 1 degree by 2 degrees Quadrangle, California and Nevada
This report is part of a folio of maps of the Walker Lake 1 o x 2 o quadrangle, California and Nevada, prepared under the Conterminous United States Mineral Assessment Program. The folio includes geological, geochemical, and geophysical maps, as well as mineral resource assessment maps which identify selected known or possible mineral-deposit environments in the quadrangle. The geochemical maps show the distributioins of selected individual elements (Chaffee and others 1988a, b, c, d) and the distributions of selected groups of elements (Chaffee, 1988a, b). Discussions accompanying the individual element maps are restricted to possible mineral residences of the individual elements as well as to what types of mineral deposits and environments may be represented by anomalies of a particular element. Discussions accompanying the multielement maps describe the types of mineral deposits that may be related to each element group and indicate the most favorable localities for these deposits.
Summary geochemical maps for samples of rock, stream sediment, and nonmagnetic heavy-mineral concentrate, east part of the Raymond Peak Roadless Area, Alpine County, California
The Raymond peak Roadless Area consists of two separate units. The west part (5985), about 12 miles southwest of Markleeville in Stanislaus National Forest, has been studied separately as part of the Mokelumne Wilderness and vicinity (McKee and others, 1982). The east part (4985) is discussed here.
Summary geochemical maps for samples of rock, stream sediment, and nonmagnetic heavy-mineral concentrates, Carson-Iceberg and Leavitt Lake Roadless Areas, Alpine, Mono, and Tuolumne counties, California
The Carson-Iceberg and Leavitt Lake Roadless Areas (the study area) lie near the crest of the Sierra Nevada in central California. The study area encompasses approximately 219,630 acres in the Stanislaus and Toiyabe National Forests in Alpine, Mono, and Tuolumne Counties. The area is dominated by rugged topography typical of the high Sierra Nevada. Elevations range from about 4,920 feet at Donnells Reservoir, at the southwestern corner of the study area, to 11,570 feet at Leavitt Peak, along the southwest boundary of the Leavitt Lake Roadless Area.
Summary geochemical maps for samples of rock, stream sediment, and nonmagnetic heavy-mineral concentrate, Cypress Roadless Area, Kern County, California
The Cypress Roadless Area comprises approximately 3 square miles (1,949 acres) of Sequoia National Forest, Kern County, California. The area is at the southern end of the Sierra Nevada, approximately 30 miles east-northeast of Bakersfield, and 2.5 miles and 3.5 miles south-southeast of the communities of Bodfish and Lake Isabella, respectively (index map). Geochemical sampling was conducted during 1980 and 1981. This report summarizes the results of that investigation and provides details of the geochemical evaluation used in the final mineral resource assessment of the study area (Kennedy and others, 1983). Map A shows the locations of all sites sampled for this report and the distributions of anomalous concentrations of 4 elements in 33 samples of rock, 5 elements in 34 samples of minus-60-mesh stream sediment, and 11 elements in 33 samples of nonmagnetic heavy-mineral concentrate derived from stream sediment. Map B shows outlines of those drainage basins containing samples of stream sediment and concentrate with anomalous concentrations and also shows weighted values for each outlined basin based on the number of elements with anomalous concentrations in each stream-sediment and concentrate sample and on the degree to which these concentrations are anomalous in each sample.
Summary geochemical maps for samples of rock, stream sediment, and nonmagnetic heavy-mineral concentrate, Pyramid Roadless Area, El Dorado County, California
The Wilderness Act (Public Law 88-577, September 3, 1964) and related acts require the U.S. Geological Survey and the U.S. Bureau of Mines to survey certain areas on Federal lands to determine their mineral resource potential. Results must be made available to the public and be submitted to the President and the Congress. This report presents the results of a geochemical survey of the Pyramid Roadless Area (5203) in the Eldorado National Forest and Lake Tahoe Basin Management Unit, El Dorado County, California. This roadless area was classified as a further planning area during the Second Roadless Area Review and Evaluation (RARE II) by the U.S. Forest Service, January 1979. The Pyramid Roadless Area lies near the crest of the Sierra Nevada about 75 miles east of Sacramento, California. the area, which is adjacent to and almost encircles the Desolation Wilderness, encompasses approximately 31,400 acres in Eldorado National Forest and the Lake Tahoe Basin Management Unit in El Dorado County, California. The area is dominated by deep rugged canyons that run eastward from the Sierra Nevada crest to Lake Tahoe basin and westward toward the Sacramento Valley. Elevations range from about 5,500 feet along Big Silver Creek on the west side of the study area to 8,895 feet at Echo Peak along the southeastern side of the roadless area. Geochemical sampling was conducted during 1982. This report summarizes the results of that investigation and provides details of the geochemical evaluation used in producing the final mineral resource assessment of the study area (Armstrong and others, 1983).
Geochemical evaluation of the Winchester Roadless Area, Cochise County, Arizona
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Summary geochemical maps, Hoover Wilderness and adjacent study area, Mono and Tuolumne counties, California
The Hoover Wilderness and the adjacent Hoover Extension (East), Hoover Extension (West), and Cherry Creek A Roadless Areas (the adjacent study area) encompass approximately 153,900 acres (241 mi 2 ; 623 km 2 ) in the Inyo, Stanislaus, and Toiyabe Naitonal Forests, Mono and Tuolumne Counties, Calif. These two areas lie along and mostly east of the crest of the Sierra Nevada, along the north and east sides of Yosemite National Park. Elevations vary from a high of 12,446 ft (3,793 m) on the crest of the Sierra Nevada to a low of about 6,500 ft (1,981 m) near the Bridgeport Ranger Station. Access to the Hoover Wilderness and adjacent study area is by U.S. Highway 395, California State Highways 108 (Sonora Pass) and 120 (Tioga Pass), and by other paved and graded roads that lead off of these U.S. and State highways.
Analytical results and sample locality maps for stream-sediment, heavy-mineral-concentrate, and rock samples, Kings River, Rancheria, Agnew, and Oat Mountain Roadless Areas, Fresno County, California
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Scoresum - A technique for displaying and evaluating multi-element geochemical information, with examples of its use in regional mineral assessment programs
A technique called SCORESUM was developed to display a maximum of multi-element geochemical information on a minimum number of maps for mineral assessment purposes. The technique can be done manually for a small analytical data set or can be done with a computer for a large data set. SCORESUM can be used with highly censored data and can also weight samples so as to minimize the chemical differences of diverse lithologies in different parts of a given study area. The full range of reported analyses for each element of interest in a data set is divided into four categories. Anomaly scores — values of O (background), 1 (weakly anomalous), 2 (moderately anomalous), and 3 (strongly anomalous) — are substituted for all of the analyses falling into each of the four categories. A group of elements based on known or suspected association in altered or mineralized areas is selected for study and the anomaly scores for these elements are summed for each sample site and then plotted on a map. Some of the results of geochemical studies conducted for mineral assessments in two areas are briefly described. The first area, the Mokelumne Wilderness and vicinity, is a relatively small and geologically simple one. The second, the Walker Lake 1° × 2° quadrangle, is a large area that has extremely complex geology and that contains a number of different mineral deposit environments. These two studies provide examples of how the SCORESUM technique has been used (1) to enhance relatively small but anomalous areas and (2) to delineate and rank areas containing geochemical signatures for specific suites of elements related to certain types of alteration or mineralization.
Mineral resource potential of the Hoover Wilderness and adjacent Roadless Areas, central Sierra Nevada, California
No abstract available.
Geochemical maps showing distributions of anomalous element concentrations and of anomalous drainage basins, Mokelumne Wilderness and contiguous roadless areas, central Sierra Nevada, California
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Geochemical anomaly map of the Sugarloaf Roadless Area, Mineral and Esmeralda counties, Nevada
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Mineral resource potential map of the Sugarloaf Roadless Area, Esmeralda and Mineral Counties, Nevada
No abstract available.