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Search indexed USGS publications on groundwater, aquifers, geologic maps, mineral resources and earthquakes. Explore source records by subject and place.

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At least 505 records · Page 28Linked to original sources
USGS1944

The differentiation of magnesite from dolomite in concentrates and tailings

A new method is presented here for differentiating magnesite from dolomite in crushed materials. This method is based on the essentially different temperatures at which these minerals undergo thermal decomposition. The resulting lowly birefringent periclase is easily distinguished microscopically from the highly birefringent dolomite. This method is based on the ease of recognition of the periclase which permits rapid counting and gives reliable quantitative data on mineral composition. A method is given for staining thermally treated specimens for the determination of the distribution of these minerals in rock fragments.

Economic Geology↗
USGS1975

The interior of the earth

The center of the Earth lies nearly 4,000 miles beneath our feet. At present the nature of the Earth's interior is known only from indirect evidence collected from studies of rocks and minerals, seismic waves, heat flow from the interior, and the Earth's gravity and magnetic field and through comparisons of the Earth with other planets, with meteorites, and with the Sun and other stars.

General Interest Publication↗
USGS2009

Selected Geochemical Data for Modeling Near-Surface Processes in Mineral Systems

The database herein was initiated, designed, and populated to collect and integrate geochemical, geologic, and mineral deposit data in an organized manner to facilitate geoenvironmental mineral deposit modeling. The Microsoft Access database contains data on a variety of mineral deposit types that have variable environmental effects when exposed at the ground surface by mining or natural processes. The data tables describe quantitative and qualitative geochemical analyses determined by 134 analytical laboratory and field methods for over 11,000 heavy-mineral concentrate, rock, sediment, soil, vegetation, and water samples. The database also provides geographic information on geology, climate, ecoregion, and site contamination levels for over 3,000 field sites in North America.

Data Series↗
USGS2022

Arkansas and Landsat

Scenic Arkansas certainly lives up to its nickname, “The Natural State.” The Ozark Plateau and Ouachita Mountains boast stunning views, vast resources, and recreation. Hardwood and pine forests cover one-half of the State. The major rivers—Arkansas, Ouachita, Red, and White—offer recreation and navigation as they drain toward the Mississippi River, which forms the State’s eastern border. Smaller streams and rivers, reservoirs, and rice fields serve as homes for wildlife as well, including birds migrating along the Mississippi Flyway. Agriculture has always been a key industry in Arkansas, which is the top rice producer in the United States. Poultry, soybeans, cotton, cattle, and timber are among other agricultural products that contribute to the State’s economy. The aquaculture industry has diversified from just goldfish to more than 20 species of fish and crustaceans. Geological features include waterfalls, limestone caves, and the country’s only active diamond mine, Crater of Diamonds State Park, where visitors can keep any rock or mineral they find in the volcanic crater. Hot Springs National Park—within the city of Hot Springs—features thermal springs of water heated deep belowground that follow a fault line of the Ouachita Mountains up to the surface. Here are a few ways Landsat has benefited Arkansas.

Arkansas↗
USGS2002

Generalized surficial geologic map of the Pueblo 1° x 2° quadrangle, Colorado

Fifty-three types of surficial geologic deposits and residual materials of Quaternary age are described in a pamphlet and located on a map of the greater Pueblo area, in part of the Front Range, in the Wet and Sangre de Cristo Mountains, and on the plains east of Colorado Springs and Pueblo. Deposits formed by landslides, wind, and glaciers, as well as colluvium, residuum, alluvium, and others are described in terms of predominant grain size, mineral or rock composition (e.g., gypsiferous, calcareous, granitic, andesitic), thickness, and other physical characteristics. Origins and ages of the deposits and geologic hazards related to them are noted. Many lines drawn between units on our map were placed by generalizing contacts on published maps. However, in 1997-1999 we mapped new boundaries as well. The map was projected to the UTM projection. This large map area extends from near Salida (on the west edge), eastward about 107 mi (172 km), and from Antero Reservoir and Woodland Park on the north edge to near Colorado City at the south edge (68 mi; 109 km).

Colorado↗
USGS2006

Isotopic ages of rocks in the northern Front Range, Colorado

These maps, and the tables that accompany them, are a compilation of isotopic age determinations of rocks and minerals in four 1:100,000 quadrangles in the northern and central Front Range, Colorado. Phanerozoic (primarily Tertiary and Cretaceous) age data are shown on one map; Proterozoic data are on the other. A sample location map is included for ease of matching specific localities and data in the tables to the maps. Several records in the tables were not included in the maps because either there were ambiguous dates or lack of location precluded accurate plotting.

Open-File Report↗
USGS1967

Mineral appraisal of the Flattery Rocks, Quillayute Needles, and Copalis National Wildlife Refuges, Washington

The Flattery Rocks, Quillayute Needles, and Copalis National Wildlife Refuges lie off the Pacific coast of the Olympic Peninsula between Cape Flattery and Grays Harbor. They have a total land area of 247 acres and consists of numerous small islands, sea stacks and rocks that rise above a wave-cut platform. The refuges are in a belt of intensely folded and faulted marine sedimentary and volcanic rocks of early Eocene to Pliocene age. Pleistocene glaciofluvial deposits blanket the Tertiary strata along this coastal belt. The disturbed belt borders the eastern margin of a depositional basin on the continental shelf that probably contains a thick sequence of late Tertiary rocks.

Washington↗