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G. L. Raines

Publications and source records attributed to G. L. Raines.

At least 37 records · Page 2Linked to original sources
USGS1987

The Conterminous United States Mineral Assessment Program: Background information to accompany folio of geologic and mineral resource maps of the Silver City 1° x 2° quadrangle, New Mexico and Arizona

The Silver City 1° x 2° quadrangle, consisting of about 20,650 km2 in southwestern New Mexico and southeastern Arizona, has been investigated by a multidisciplinary research team for the purpose of assessing its mineral resource potential. The results of this investigation are in a folio of 21 maps that contain detailed information on the geology, geochemistry, geophysics, mineral deposits, and potential mineral resources of the quadrangle. This Circular provides background information on the various studies and integrates the component maps. It contains an extensive selected bibliography pertinent to the geology and mineral deposits of the quadrangle. The quadrangle has produced more than $3.5 billion in mineral products since about 1850 and contains significant resources of gold, silver, copper, molybdenum, lead, zinc, iron, manganese-iron, zeolite minerals, and possibly tin and tungsten.

Arizona, New Mexico↗
USGS1985

Near-infrared spectra of West Shasta gossans compared with true and false gossans from Australia and Saudi Arabia

The near-infrared spectra of a suite of outcrop samples of massive sulfide gossans and false gossans representing three different weathering environments were measured and studied with X-ray, scanning electron microscope, and energy dispersive X-ray. Gossans that formed in a humid tropical environment are represented by samples from the Mt. Isa area, Queensland, Australia, and gossans that formed in an arid environment are represented by samples from several locations in Saudi Arabia. The gossans of the West Shasta massive sulfide district in California represent a weathering environment intermediate between these two extremes.On the basis of these spectral measurements, true gossans after massive sulfide deposits have spectra in the 800 to 2,500 nanometer (nm) region that are distinctly different from the spectra of false gossans. In the humid tropical environment, highly leached, newly formed kaolin minerals in the gossan cause spectral differences at about 1,400 to 2,200 nm. In the arid environment, true gossans preserve talc and minor mica from the massive sulfide deposit; these minerals are not observed in false gossans. These minerals result in spectral differences in the 2,200- to 2,300-nm region. In addition, true gossans generally have goethite spectral bands at about 900 nm as opposed to hematite spectral bands at about 850 nm for the false gossans.False gossans are not known in the West Shasta district; however, the gossan at the largest deposit, Iron Mountain, is a true gossan that has the distinctive spectral features of goethite at about 900 nm and diaspore in the 1,400- to 2,500-nm region. The other gossans also have the spectral features of goethite, but they contain a less leached mixture of kaolinite plus illite and have distinctive spectral features in the 1,400- to 2,500-nm region. These spectral differences define two groups of West Shasta gossans--inner gossans in large deposits and outer gossans at the margins of large deposits and in lesser massive sulfide deposits.

Economic Geology↗
USGS1985

Remotely sensed limonite anomaly on Lordsburg Mesa, New Mexico: Possible implications for uranium deposits

We have identified a large, anomalously limonitic area in Cenozoic gravels on Lordsburg Mesa near Lordsburg, New Mexico, using Landsat images. Our interpretation of the geophysical and geochemical data suggests the exploration hypothesis that the Lordsburg Mesa limonite anomaly is the surface expression of a chemical trap that may contain concentrations of uranium similar to calcrete-uranium deposits. Ground water originating in the Big Burro Mountains, where uranium vein deposits are known, drains through the Lordsburg Mesa area. This ground water is apparently forced near the surface by a buried bed-rock ridge along the west side of the limonite anomaly. The resulting changes in ground-water chemistry may be precipitating uranium along the eastern margin of the limonite anomaly.

Economic Geology↗
USGS1983

Airborne biogeophysical mapping of hidden mineral deposits

Airborne survey techniques have been developed to detect and map forest canopies affected by metal-induced stress. A high spectral resolution airborne spectroradiometer system, used over a known forest-covered copper soil anomaly, has revealed previously unknown spectral changes in the near-infrared chlorophyll absorption spectrum. The metal-induced spectral shifts have subsequently been reproduced in the laboratory at Columbia University. Waveform analysis techniques specifically designed for computer analysis of the high spectral resolution aircraft data filter out the very strong background noise introduced by variations in normal, unstressed vegetation canopy and by topographic effects. The wave-form method proves most effective in extracting the subtle spectral indicators of metal-induced stress. The analytic method is a unique frequency domain technique made possible by the high spectral resolution of the 500-channel spectroradiometer system. The biogeophysical technique is demonstrated by three mapping surveys of Cotter Basin, Montana, and Spirit Lake, Washington. This airborne mapping technique presents new application opportunities in large areas of the world where heavy forest cover has in the past made geologic and geophysical exploration tedious and expensive. The tree cover with widespreading and deeply penetrating root systems is turned to an advantage in the airborne biogeophysical technique by detecting metal-induced changes in the chlorophyll reflectance spectrum.

Montana↗