Publications

The U.S. Geological Survey conducted a detailed gravity study along part of the Los Angeles Regional Seismic Experiment (LARSE) transect across the San Fernando Basin and Transverse Ranges to help characterize the structure underlying this area. 249 gravity measurements were collected along the transect and to augment regional coverage near the profile. An isostatic gravity low of 50-60 mGal refle

This data set maps and describes the geology of the Porcupine Wash 7.5 minute quadrangle, Riverside County, southern California. The quadrangle, situated in Joshua Tree National Park in the eastern Transverse Ranges physiographic and structural province, encompasses parts of the Hexie Mountains, Cottonwood Mountains, northern Eagle Mountains, and south flank of Pinto Basin. It is underlain by a ba

For many oil and gas fields, estimates of ultimate recovery (the sum of cumulative production plus estimated reserves) tend to increase from one year to the next, and the gain is called reserve growth. Forecasts of reserve growth by the U.S. Geological Survey rely on statistical analyses of historical records of oil and gas production and estimated reserves. The preproposal in this Open-File Repor

Oil test wells can provide information on the depth, age, inclination, porosity, permeability, density, faulting, folding, and organic content of geologic formations mapped at the surface, or on units not recognized in surface outcrops. Formation density, as expressed in sonic and density logs commonly obtained when wells are drilled, has become increasingly important in making a crustal-scale 3-D

No abstract available.

Basin-center accumulations, a type of continuous accumulation, have spatial dimensions equal to or exceeding those of conventional oil and gas accumulations, but unlike conventional fields, cannot be represented in terms of discrete, countable units delineated by downdip hydrocarbon-water contacts. Common geologic and production characteristics of continuous accumulations include their occurrence

The Roseburg 30' x 60' Quadrangle covers the southeastern margin of the Oregon Coast Range and its tectonic boundary with Mesozoic terranes of the Klamath Mountains (see figures 1 and 2 in pamphlet, also shown on map sheet). The geologic framework of the Roseburg area was established by the pioneering work of Diller (1898), Wells and Peck, (1961) and Ewart Baldwin (1974) and his students (see figu

No abstract available.

Alaska, the least explored of all United States regions, is estimated to contain approximately 40% of total U.S. undiscovered, technically recoverable oil and natural-gas resources, based on the most recent U.S. Department of the Interior (U.S. Geological Survey and Minerals Management Service) estimates. Northern Alaska, including the North Slope and adjacent Beaufort and Chukchi continental shel

Geologic resource assessments describe the location, general characteristics, and estimated volumes of resources, whether in situ or technically recoverable. Such compilations are only an initial step in economic resource evaluation. This paper identifies, by examples from the Illinois and Appalachian basins, the salient features of a geologic assessment that assure its usefulness to downstream ec

Using gridded high-resolution aeromagnetic data, the performance of several automated 3-D depth-to-source methods was evaluated over shallow control sources based on how close their depth estimates came to the actual depths to the tops of the sources. For all three control sources, only the simple analytic signal method, the local wavenumber method applied to the vertical integral of the magnetic

This study, one in a series, reports bulk chemical composition of rock samples collected from a core, referred to as Measured Section J, drilled at a site that subsequently was developed into the Enoch Valley phosphate mine in southeastern Idaho. The core is continuous and cuts through the entire thickness of the Meade Peak Phosphatic Shale Member of the Phosphoria Formation. The steeply dipping M