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No abstract available....

Lopez Reservoir is a multipurpose impoundment that was filled during a 30-week period following a series of intense storms during the winter 1968-69. The reservoir is used for flood control, water supply, and recreation, including swimming, fishing, and boating. At full pool Lopez Reservoir has a surface area of 974...

Titanium minerals in amounts equivalent to a significant portion of present world production are moved but not recovered from mines of other commodities. Resources of this type total in the millions of tons of contained TiO2. Among the possible sources for byproduct titanium are (1) ilnenite and minor rutile detrital...

Metalliferous mineral deposits of the southeastern Pacific region include: (1) hydrothermal, magmatic, and sedimentary deposits of the Andean region, one of the great mineral belts of the world; 2) Scattered hydrothermal mineral occurrences in the Antarctic Peninsula; and 3) metal-enriched pelagic sediments, ferromanganese nodules, and volcanic rocks(?) in the southeast...

Geochemical sampling of bedrock has revealed anomalous copper, silver, molybdenum, gold, arsenic, mercury, zinc, and cobalt in meta-iron-formation in the Blue Lead Mountain area 5 miles (8 kilometres) north-northwest of Keystone, S. Dak. The anomalies are in complexly folded and faulted iron-formation. Metal content decreases sharply in the surrounding rocks....

Three types of copper deposits-porphyry, strata-bound, and massive sulfide-are described, and the distributions of tonnages and grades for 267 deposits are compared with normal and lognormal frequency distributions. The relationships between grades and tonnages are analyzed by examining the correlation coefficients of these variables. Conclusions reached include the following: (1)...

Volcanic and sedimentary rocks of late Precambrian age include four formations of volcanic rocks (three newly recognized) and four formations of sedimentary rocks, with a total apparent thickness of more than 60,000 feet. The Siemens Creek Formation, composed of: thin basalt flows, and the overlying Kallander Creek Formation, composed predominantly of...

Geochemical exploration is an important part of copper-resource evaluation. A large number of geochemical exploration techniques, both proved and untried, are available to the geochemist to use in the search for new copper deposits. Analyses of whole-rock samples have been used in both regional and local geochemical exploration surveys in the...

The Milligen Formation at and near its type locality in the Wood River area is considerably older than and unrelated to rocks of Early Mississippian age called Milligen Formation in the Lost River Range and other ranges of east-central Idaho. Conodont faunas were found in limestones of a thin upper...

Permian, Pennsylvanian, Mississippian, Devonian, and Silurian marine rocks of diverse facies are brought together in a complex of six thrust sheets in the Fish Creek Reservoir area on the north edge of the Snake River Plain, Idaho. The lowest structural element, the parautochthon, is made of more than 450 m...

The author has identified the following significant results. Work with the Image 100 clearly demonstrates that radiance values of LANDSAT data can be used for correlation of geologic formations across international boundaries. The Totora Formation of the Corocoro Group of Tertiary age was traced from known outcrops near Tiahuanaco, Bolivia,...

Along Wildhorse Creek in the northeastern Pioneer Mountains, autochthonous Ordovician and Silurian rocks of an eastern carbonate assemblage are exposed in a structural window through allochthonous flysch deposits of the Mississippian Copper Basin Group. Graptolite-bearing Middle and Upper Ordovician dolomite and cherty dolomite 210 ft (64 m) thick are lithologically...

The Sapo Alegre prospect, a small porphyry copper-molybdenum occurrence in west-central Puerto Rico, is characterized by distinct zones of alteration and mineralization of quartz diorite porphyry. A biotite-chlorite zone in the porphyry near its contact with surrounding metavolcanic rocks contains copper, molybdenum, gold, silver, selenium, and tellurium. A quartz-sericite-pyrite zone...

 Recent resource estimates have been stimulated by national concern over present and pending shortages of energy and mineral resources. Although some believe that the resource base of a commodity is the total amount in the crust, the energy consumption for mining and milling under present technology suggests that grades of...

The Rico district is in the Dolores River valley at the east end of Dolores County in southwestern Colorado. Mining has been actively carried on in the district since 1879. In the early days, silver was the chief product and was mined largely from Newman Hill southeast of the town...

This map was first published as a printed edition in 1974. The geologic data have now been captured digitally and are presented here along with images of the printed map sheets. The map encompasses the area of four 7.5-minute quadrangles between 39º15' and 39º 30'N and 106º15' and 106º30'W in...

No abstract available....

A developing interest in the normal distributions of potentially harmful substances in the natural environment has prompted a baseline study of a virtually pristine region along the northern coast of Alaska. The information reported here outlines the background values of copper, lead, zinc, cadmium, mercury, and arsenic in the nearshore...

Water-quality data, collected at 57 hydrologic bench-mark stations in 37 States, allow the definition of water quality in the 'natural' environment and the comparison of 'natural' water quality with water quality of major streams draining similar water-resources regions. Results indicate that water quality in the 'natural' environment is generally very...

Metalliferous mineral deposits of the southeastern Pacific region include: (1)hydrothermal, magmatic, and sedimentary deposits of the Andean region, one of the great mineral belts of the world; (2) scattered hydrothermal deposits in the Antarctic Peninsula; and (3) metal-enriched pelagic sediments and ferromanganese nodules on the seafloor. Andean metalliferous deposits, the chief topic of this report,...

A review of the calderas in the San Juan volcanic field, southwestern Colorado, indicates that lead, zinc, copper, gold, and silver mineralization took place in and near calderas which had complex histories of postsubsidence intrusive and extrusive igneous activity. Most known ore occurs in veins that follow fractures formed during...