Publications
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Early to middle Jurassic salt in Baltimore Canyon trough
A pervasive, moderately deep (5-6 s two-way traveltime), high-amplitude reflection is traced on multichannel seismic sections over an approximately 7500 km² area of Baltimore Canyon Trough. The layer associated with the reflection is about 25 km wide, about 60 m thick in the center, and thins monotonically laterally, though asymmetrically, at the edges. Geophysical characteristics are compatible w
Authors
B. Ann McKinney, Myung W. Lee, Warren F. Agena, C. Wylie Poag
Statistical guides to estimating the number of undiscovered mineral deposits: an example with porphyry copper deposits
Estimating numbers of undiscovered mineral deposits is a fundamental part of assessing mineral resources. Some statistical tools can act as guides to low variance, unbiased estimates of the number of deposits. The primary guide is that the estimates must be consistent with the grade and tonnage models. Another statistical guide is the deposit density (i.e., the number of deposits per unit area of
Authors
Donald A. Singer, W. D. Menzie
Porphyry copper deposit density
Estimating numbers of undiscovered mineral deposits has been a source of unease among economic geologists yet is a fundamental task in considering future supplies of resources. Estimates can be based on frequencies of deposits per unit of permissive area in control areas around the world in the same way that grade and tonnage frequencies are models of sizes and qualities of undiscovered deposits.
Authors
Donald A. Singer, Vladimir Berger, W. David Menzie, Byron R. Berger
Discovery sequence and the nature of low permeability gas accumulations
There is an ongoing discussion regarding the geologic nature of accumulations that host gas in low-permeability sandstone environments. This note examines the discovery sequence of the accumulations in low permeability sandstone plays that were classified as continuous-type by the U.S. Geological Survey for the 1995 National Oil and Gas Assessment. It compares the statistical character of historic
Authors
E.D. Attanasi
Tar yields from low-temperature carbonization of coal facies from the Powder River Basin, Wyoming, USA
Tar yields from low-temperature carbonization correlate with the amount of crypto-eugelinite in samples selected to represent petrographically distinct coal facies of the Wyodak-Anderson coal zone. Tar yields from Fischer Assay range from <1 to 11 wt.% on a dry basis and correspond (r = 0.72) to crypto-eugelinite contents of the coal that range from 15 to 60 vol.%. Core and highwall samples were o
Authors
Ronald W. Stanton, Peter D. Warwick, Sharon M. Swanson
Origin of the Bering Sea salient
Our investigations in Alaska and Russia show that the curved orogen of the Bering Strait region is a composite feature that formed as a result of multiple superimposed events and cannot be related to latest Cretaceous–early Tertiary east-west shortening. Relations interpreted to record east-west shortening include the Chukchi syntaxis, deformation on Seward and Chukotka Peninsulas, the map pattern
Authors
J.M. Amato, J. Toro, Thomas E. Moore
Preliminary geologic map of the Nevada and Arizona parts of the Mount Manchester quadrangle
This map was prepared as part of the STATEMAP component of the National Cooperative Geologic Mapping Program in cooperation with the U.S. Geological Survey.
Authors
Kyle House, Keith A. Howard, Philip A. Pearthree, John W. Bell
Weathering of the meade peak phosphatic shale member, phosphoria formation: Observations based on uranium and its decay products
Variably weathered outcrop samples of the Meade Peak Phosphatic Shale Member of the Phosphoria Formation have 5-10% of the contained uranium (U) in a form readily extractable by 0.1 M sodium bicarbonate. Fission track radiography of outcrop samples and other less-weathered channel and core samples indicate that this mobile fraction of U is likely hosted by organic matter, secondary iron oxides and
Authors
Robert A. Zielinski, James R. Budahn, Richard I. Grauch, J. B. Paces, K. R. Simmons
Proceedings of the twentieth annual meeting of the Society for Organic Petrology
The Society for Organic Petrology (TSOP; pronounced "Tee'-sop") was established in 1984 to consolidate and foster the organizational activities of scientists and engineers involved with coal petrology, kerogen petrology, organic geochemistry, and related disciplines. The following report, "Proceedings of the Twentieth Annual Meeting of The Society for Organic Petrology" (ISSN 1060-7250), features
A bootstrap approach to computing uncertainty in inferred oil and gas reserve estimates
This study develops confidence intervals for estimates of inferred oil and gas reserves based on bootstrap procedures. Inferred reserves are expected additions to proved reserves in previously discovered conventional oil and gas fields. Estimates of inferred reserves accounted for 65% of the total oil and 34% of the total gas assessed in the U.S. Geological Survey’s 1995 National Assessment of oil
Authors
Emil D. Attanasi, Timothy C. Coburn
Size-frequency analysis of petroleum accumulations in selected United States plays: potential analogues for frontier areas
This report presents the petroleum accumulation size-frequency relationships of selected mature plays assessed in the U.S. Geological Survey's 1995 National Assessment of Oil and Gas Resources. The plays provide assessors with potential analogue models from which to estimate the numbers of undiscovered accumulations in medium and smaller size categories. Each play selected was required to have at
Authors
Emil D. Attanasi, Philip A. Freeman