Publications
Publications from the staff of the Geology, Minerals, Energy, and Geophysics Science Center
Filter Total Items: 2350
Electrical conductivity images of active and fossil fault zones
We compare recent magnetotelluric investigations of four large fault systems: (i) the actively deforming, ocean-continent interplate San Andreas Fault (SAF); (ii) the actively deforming, continent-continent interplate Dead Sea Transform (DST); (iii) the currently inactive, trench-linked intraplate West Fault (WF) in northern Chile; and (iv) the Waterberg Fault/Omaruru Lineament (WF/OL) in Namibia,
Authors
O. Ritter, A. Hoffmann-Rothe, Paul A. Bedrosian, U. Weckmann, V. Haak
Questa baseline and pre-mining ground-water quality invistigation. 13. Mineral microscopy and chemistry of mined and unmined porphyry molybdenum mineralization along the Red River, New Mexico: Implications for ground- and surface-water quality
This report is one in a series presenting results of an interdisciplinary U.S. Geological Survey (USGS) study of ground-water quality in the lower Red River watershed prior to open-pit and underground molybdenite mining at Molycorp's Questa mine. The stretch of the Red River watershed that extends from just upstream of the town of Red River to just above the town of Questa includes several mineral
Authors
Geoff Plumlee, Heather Lowers, Steve Ludington, Alan Koenig, Paul Briggs
By
Water Resources Mission Area, Ecosystems Mission Area, Mineral Resources Program, Toxic Substances Hydrology, Environmental Health Program, Geology, Geophysics, and Geochemistry Science Center, Geology, Minerals, Energy, and Geophysics Science Center, New Mexico Water Science Center, Denver Microbeam Laboratory
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
A predictive penetrative fracture mapping method from regional potential field and geologic datasets, southwest Colorado Plateau, U.S.A.
Some aquifers of the southwest Colorado Plateau, U.S.A., are deeply buried and overlain by several impermeable units, and thus recharge to the aquifer is probably mainly by seepage down penetrative fracture systems. This purpose of this study was to develop a method to map the location of candidate deep penetrative fractures over a 120,000 km2 area using gravity and aeromagnetic anomaly data toget
Authors
Mark E. Gettings, Mark Bultman
Authigenesis of trace metals in energetic tropical shelf environments
We evaluated authigenic changes of Fe, Mn, V, U, Mo, Cd and Re in suboxic, periodically remobilized, tropical shelf sediments from the Amazon continental shelf and the Gulf of Papua. The Cd/Al, Mo/Al, and U/Al ratios in Amazon shelf sediments were 82%, 37%, and 16% less than those in Amazon River suspended sediments, respectively. Very large depletions of U previously reported in this environment
Authors
E.J. Breckel, S. Emerson, Laurie S. Balistrieri
Marine mineral resources of Pacific Islands— A review of the Exclusive Economic Zones of islands of U.S. affiliation, excluding the State of Hawaii
The United States Exclusive Economic Zone (EEZ) was established in 1983 and comprises all marine areas within 200 nautical miles (370 kilometers) of the nearest U.S. land. This vast area of 3.38 million square nautical miles (11.6 million square kilometers) is about 20 percent greater than the entire land area of the United States. The resource potential of the vast mineral deposits that occur wit
Authors
James R. Hein, Brandie R. McIntyre, David Z. Piper
Stream-sediment geochemistry in mining-impacted streams: Sediment mobilized by floods in the Coeur D'Alene-Spokane River system, Idaho and Washington
Environmental problems associated with the dispersion of metal-enriched sediment into the Coeur d'Alene-Spokane River system downstream from the Coeur d'Alene Mining District in northern Idaho have been a cause of litigation since 1903, 18 years after the initiation of mining for lead, zinc, and silver. Although direct dumping of waste materials into the river by active mining operations stopped i
Authors
Stephen E. Box, Arthur A. Bookstrom, Mohammed Ikramuddin
High resolution climate of the past 3,500 years of coastal northernmost California
No abstract available.
Authors
John A. Barron, Linda E. Heusser, Clark Alexander
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