Publications

No abstract available.

Previous chemical, geological, and hydrological information describing the physical and chemical environment of the Nevada Test Site (a Federal reserve for the testing of nuclear explosive devices) has been combined with new radiochemical and isotope data for water and rock samples in order to explain the behavior of uranium during alteration of thick sequences of rhyolitic volcanic rocks and asso

No abstract available.

No abstract available.

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Structurally complex sequences of sedimentary, volcanic, and intrusive igneous rocks characterize a nearly continuous narrow band along the Pacific coast of North America from Baja California, Mexico to southern Alaska. They occur in two modes: (1) as complexly folded but coherent sequences of graywacke and argillite that locally exhibit blueschist-grade metamorphism, and (2) as melanges containin

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 ±

No abstract available.

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

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

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

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