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Publications

Publications from the staff of the Geology, Minerals, Energy, and Geophysics Science Center

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A guide to commonly used map projections prepared for use in HyperCard, 1988

This guide briefly describes and illustrates the characteristics of 17 map projections commonly used to present thematic data. By means of simple sketches of the basic grid system of longitude and latitude known as the Earth's graticule, the guide shows examples of the following categories of map projections: planes (azimuthal), cones, cylinders, and miscellaneous. The text gives examples of thema
Authors
Tau Rho Alpha, Joe F. Vigil, Lauren Buchholz

Mineral resource assessment of the Wiseman 1° by 3° quadrangle, Alaska

No abstract available.
Authors
James D. Bliss, W. P. Brosge, J. T. Dillon, J.T. Dutro, J.B. Cathrall, J. W. Cady

Models of grades and tonnages of some lode tin deposits

Descriptive and grade/tonnage models have recently been built for many types of deposits. Such models consist of descriptions of mineralogy, host rocks, ore textures, controls, alteration, geochemical signatures, age, and tectonic settings, together with statistical models of grades, tonnages, and contained metal of deposits of each type. The models are used to identify areas that may contain undi
Authors
W. D. Menzie, B.L. Reed, Donald A. Singer

The relative contribution of accretion, shear, and extension to Cenozoic tectonic rotation in the Pacific Northwest

Large Cenozoic clockwise rotations defined by paleomagnetic data are an established fact in the Pacific Northwest, and many tectonic models have been proposed to explain them, including (1) rotation of accreted oceanic microplates during docking, (2) dextral shear between North America and northward-moving oceanic plates to the west, and (3) microplate rotation in front of an expanding Basin and R
Authors
Ray E. Wells, Paul L. Heller

Integrating spatial and frequency information in the search for kuroko deposits of the Hokuroku District, Japan

A new method (FINDER) that uses the area of influence and Bayesian statistics to aid in selection of target areas on the basis of one or more variables and multiple observations was tested with drill hole data. A previously defined bimodal distribution of Na 2 O with the low sodium group confined to a 1.5 X 3.0-km zone beneath the cluster of deposits at Fukazawa was used as a control area for one
Authors
Donald A. Singer, Ryoichi Kouda

Paleomagnetic results from the Shasta Bally Plutonic Belt in the Klamath Mountains Province, northern California

Available paleomagnetic data show approximately 100° of clockwise rotation for Permian and Triassic strata of the Eastern Klamath terrane. Jurassic strata of this terrane are rotated approximately 60° clockwise, which is comparable to rotations reported for Jurassic plutons that occur elsewhere in the Klamath Mountains province. Paleomagnetic data obtained during the present study from the Shasta
Authors
Edward A. Mankinen, William P. Irwin, C. Sherman Grommé

Climate and ephemeral-stream processes: Twentieth-century geomorphology and alluvial stratigraphy of the Little Colorado River, Arizona

During the first 40 years of the twentieth century, erosion was the dominant geomorphic process affecting the morphology of the Little Colorado River channel. The discharge regimen was one of frequent large floods and high annual discharge that created a wide sandy channel free of vegetation. In the 1940s and early 1950s, average annual precipitation declined, reducing annual discharge to about 57
Authors
Richard Hereford