Publications
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Age measurements of potassium-bearing sulfide minerals by the 40Ar/39Ar technique
K-Ar ages have been determined for sulfide minerals for the first time. The occurrence of adequate amounts of potassium-bearing sulfides with ideal compositions K3Fe10S14 (∼10 wt.% K) and KFe2S3 (∼16 wt.% K) in samples from a mafic alkalic diatreme at Coyote Peak, California, prompted an attempt to date these materials. K3Fe10S14, a massive mineral with conchoidal fracture, gives an age of 29.4 ±
Authors
G.K. Czamanske, M. A. Lanphere, Richard C. Erd, M. C. Blake
Regional mineral resource assessment in Alaska, a case history
No abstract available.
Authors
Donald A. Singer, W. D. Menzie, John H. DeYoung
Paleomagnetic evidence for a Late Cretaceous deformation of the Great Valley Sequence, Sacramento Valley, California
Paleomagnetic samples from five localities within the Great Valley sequence range in age from Late Jurassic to Late Cretaceous. All samples possess normal polarity, and alternating-field demagnetization experiments show that the remanence was acquired after the sequence was folded. A mean paleomagnetic pole position determined from 17 demagnetized samples is located at 72° N., 181° E., with the ra
Authors
Edward A. Mankinen
Geomagnetic paleointensities from radiocarbon‐dated lava flows on Hawaii and the question of the Pacific nondipole low
Radiocarbon ages have been published for nine basaltic lava flows on the island of Hawaii; the ages range from 2600 to somewhat older than 17,900 years B.P. By using the Thelliers' method in vacuum, geomagnetic paleointensity values were obtained from eight of the lavas; the ninth proved unsuitable. The paleointensities for the four youngest flows (2600–4600 years B.P.) yield virtual dipole moment
Authors
Robert S. Coe, Sherman Gromme, Edward A. Mankinen
Geomagnetic polarity event recorded at 1.1 m.y. B.P. on Cobb Mountain, Clear Lake volcanic field, California
Paleomagnetic studies show that a normal polarity event within the Matuyama reversed polarity epoch is recorded by one of the volcanic units on Cobb Mountain in northern California. K-Ar age determinations show that this event has an age of 1.12 ± 0.02 m.y. and clearly preceded the Jaramillo normal polarity event. These data provide the first confirmation from a subaerial volcano that a brief pola
Authors
Edward A. Mankinen, J.M. Donnelly, C. S. Grommé
Natural radioactivity in geothermal waters, Alhambra Hot Springs and nearby areas, Jefferson County, Montana
Radioactive hot springs issue from a fault zone in crystalline rock of the Boulder batholith at Alhambra, Jefferson County, in southwestern Montana. The discharge contains high concentrations of radon, and the gross alpha activity and the concentration of adium-226 exceed maximum levels recommended by the Environmental Protection Agency for drinking water. Part of the discharge is diverted for spa
Authors
Robert B. Leonard, Victor J. Janzer
Porosity evolution, Late Miocene reefs, Almeria Province, southern Spain
No abstract available.
Authors
Augustus K. Armstrong, P. D. Snavely, Warren O. Addicott
Geologic interpretation of gravity data from the Date Creek basin and adjacent areas, west-central Arizona
A gravity survey of the Date Creek Basin and adjacent areas was conducted in June 1977 to provide information for the interpretation of basin geology. A comparison of facies relations in the locally uraniferous Chapin Wash Formation and the position of the Anderson mine gravity anomaly in the Date Creek Basin suggested that a relationship between gravity lows and the development of thick lacustrin
Authors
James K. Otton, Jeffrey C. Wynn
Geology and coal resources of the Hanging Woman Creek Study Area, Big Horn and Powder River Counties, Montana
In an area of 7,200 acres (29 sq km) In the Hanging Woman Creek study area, the Anderson coal bed contains potentially surface minable resources of 378 million short tons (343 million metric tons) of subbituminous C coal that ranges in thickness from 26 to 33 feet (7.9-10.1 m) at depths of less than 200 feet (60 m). Additional potentially surface minable resources of 55 million short tons (50 mill
Authors
William Craven Culbertson, Joseph R. Hatch, Ronald H. Affolter
Map showing saturated thickness of unconsolidated aquifer, southwestern Kansas, January 1975
No abstract available.
Authors
Edwin D. Gutentag, D.H. Lobmeyer, Steven E. Slagle
Geological Survey research 1978
This U.S. Geological Survey activities report includes a summary of 1978 fiscal year scientific and economic results accompanied by a list of geologic and hydrologic investigations in progress and a report on the status of topographic mapping. The summary of results includes: (1) Mineral and water resources, (2) Engineering geology and hydrology, (3) Regional geology, (4) Principles and processes,
Authors
Feasibility and cost of using a computer to prepare landslide susceptibility maps of the San Francisco Bay region, California
No abstract available.
Authors
Evelyn B. Newman, Arthur R. Paradis, Earl E. Brabb