Skip to main content
U.S. flag

An official website of the United States government

Publications

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

Filter Total Items: 2350

The area of influence of an exploratory hole

A method is presented for calculating the area of influence of exploratory drill holes by using the size and shape of resource targets. The solution presented is for elliptical and circular targets, but the method is applicable to any shaped target. The degree to which points have been explored depends upon their distance away from a drill hole and the possible orientations of the target. Several
Authors
D.A. Singer, L. J. Drew

Natural remanent magnetization, mag¬netic properties, and oxidation of titanomagnetite in basaltic rocks from DSDP Leg 34

We have made paleomagnetic measurements and investigated the magnetic mineralogy of 24 samples of basalt and diabase from Sites 319, 320, and 321 on the Nazca plate. Sample distributions, locations, and ages of overlying sediments are as follows: Site 319, Hole 319, lat 13°01.04'S, long 101°31.46'W, 2 samples, early Miocene (N8); Site 319, Hole 319A, (same coordinates and age), 12 samples. Site 32
Authors
C. Sherman Grommé, Edward A. Mankinen

Chino Valley formation (Cambrian?) in northwestern Arizona

A thin persistent unit (maximum thickness 13 m) of probable Cambrian age in the Chino Valley region of northwestern Arizona consists of three laterally equivalent, mutually exclusive lithofacies. These are, from west to east, lithic sandstone, pebble to boulder conglomerate, and dolomite. The unit, named the Chino Valley Formation, is younger than middle Middle Cambrian and older than Devonian in
Authors
Richard Hereford

The Oligocene volcanic center at Eureka, Nevada

A volcanic center covering an area of about 80 km2 near Eureka, Nev., and active in the early Oligocene, is characterized by rhyolitic, rhyodacitic. and andesitic pyroclastic rocks, lava flows, and shallow intrusive bodies. These rocks were emplaced as intertonguing and interpenetrative units during a 5-m.y. interval; most of the volcanism was in the last 3 million years of this period (36 to 33 m
Authors
M. C. Blake, E. H. McKee, Richard F. Marvin, Miles L. Silberman, Thomas B. Nolan

Recurrent geothermally induced debris avalanches on Boulder Glacier, Mount Baker, Washington

Avalanches of snow, firn and hydrothermally altered rock and mud have been released six times since 1958 from Sherman Peak, part of the crater rim south of the main summit of Mount Baker, Wash. The avalanches traveled nearly identical paths 2.0-2.6 km down Boulder Glacier on the east slope of the volcano. Debris from at least one past avalanche can be seen as a thin bed of acidic mud in the glacie
Authors
David Frank, Austin Post, Jules D. Friedman