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R.A. Martin

Publications and source records attributed to R.A. Martin.

15 recordsLinked to original sources
USGS1987

Aeromagnetic map of the Hells Gate Roadless Area, Gila County, Arizona

The Hells Gate Roadless Area comprises about 31, 200 acres in the northern part of the Tonto National Forest. It lies beneath the Mogollon Rim between the communities of Payson and Young. The area is roughly a 4 by 15 mi strip along the deeply incised segment of Tonto Creek and along a 2 mi segment of Haigler Creek at its intersection with Tonto Creek. Elevations range from 2,960 ft in the lower Tonto Creek gorge near Gisela, in the southeastern part of the area, to 6,200 ft in the Green Valley Hills, in the northern part of the area. Local relief in the deep canyon of Tonto Creek is commonly greater than 1,000 ft. Hells Gate is the geographic name for the canyon at the confluence of Tonto Creek and Haigler Creek. Foot trails cross Tonto Creek at Hells Gate and between Houston Pocket and McDonald Pocket. Descent into Tonto Creek elsewhere is extremely difficult. The Hells Gate area lies in the central part of the Tonto Basin, which consists of Tonto Creek and tributaries draining the Mogollon escarpment and the northern Sierra Ancha. These streams dissect a table land which is the unconformable surface at the base of the Paleozoic section and the Mogollon Rim. This tableland is a part of the Colorado Plateau margin, which has been slightly structurally disrupted by late Cenozoic faulting and from which most of the Middle Proterozoic and Paleozoic strata have been stripped by subsequent erosion. Early Proterozoic rocks constitute about ninety percent of the exposed rocks in the roadless area and are composed of granite, granophyre, and intrusive and extrusive rhyolite (Conway, 1983).

Arizona↗
USGS1983

Aeromagnetic map of the Powderhorn wilderness study area and Cannibal Plateau Roadless Area, Gunnison and Hinsdale counties, Colorado

The Powderhorn Wilderness Study Area (51,000 acres or 20,640 hectares) and the contiguous Cannibal Plateau Roadless Area (29,500 acres or 11,959 hectares) are on the Gunnison County-Hinsdale County boundary, approximately 50mi (80 km) southwest of Gunnison and a few miles east of Lake City, Colo. Part of the area has been known as the Powderhorn Primitive Area. The mineral resource potential of the study area has been assessed by the U.S. Geological Survey and the U.S. Bureau of Mines; this assessment involved, besides the geologic study and economic appraisal (Sharp and others, 1983), a geophysical survey (this report) by the Geological Survey, and a geochemical survey (Sharp and Lane, 1983) by the Geological Survey and the Bureau of Mines.

Colorado↗
USGS1982

Geophysical survey of the Centennial Mountains Wilderness Study Area and contiguous areas, Beaverhead County, Montana and Clark and Fremont counties, Idaho

Parts of both the Targhee and Beaverhead National Forests are within the study area. Four contiguous parcels of land, totaling about 96,176 acres (38,922 ha) make up the area. The first of these encompasses about 46,126 acres (18,667 ha), is wholly in Montana, and includes an addition by the Bureau of Land Management. The second area, in the Targhee National Forest, consists of some 38,750 acres (15,682 ha) within Idaho. The third and fourth parcels include about 11,300 acres (4,573 ha) in the Beaverhead..and Targhee National Forests that overlies the Mt. Jefferson and Sawtell Peak areas in the eastern part of the Centennial Mountains.

Idaho, Montana↗
USGS1980

Preliminary report on the mineral resources of the Powderhorn Instant study area, Gunnison and Hinsdale counties, Colorado

The Powderhorn Instant Study Area covers approximately 51,000 acres of land under BLM administration located about 80 km (50 mi) southwest of Gunnison, Colorado. A mineral resource survey, made in 1979 by the U.S. Geological Survey and the U.S. Bureau of Mines, indicates that both the mineral potential and the energy potential for the Powderhorn Instant Study Area are low. This report is based on geologic and geochemical investigations, examination of prospects, and an aeromagnetic survey. Spectrographic analyses were made of approximately 120 stream-sediment and rock samples. No mining districts are located within the study area.

Colorado↗