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Publications

Results from our Program’s research and minerals information activities are published in USGS publications series as well as in outside journals.  To follow Minerals Information Periodicals, subscribe to the Mineral Periodicals RSS feed.

Filter Total Items: 2592

Age measurements of potassium-bearing sulfide minerals by the 40Ar/39Ar technique 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...
Authors
G.K. Czamanske, M. A. Lanphere, Richard C. Erd, M.C. Blake

Porphyry-type metallization and alteration at La Florida de Nacozari, Sonora, Mexico Porphyry-type metallization and alteration at La Florida de Nacozari, Sonora, Mexico

Pervasive secondary biotite-rich mineral assemblages, characteristic of potassic alteration found in the cores of most commercial porphyry copper systems, are associated spatially with a conspicuous color and a geochemical anomaly at La Florida de Nacozari, Sonora. These composite biotite-magnetite assemblages, with or without actinolite, quartz, rutile, sphene, chalcopyrite, and pyrite
Authors
Ted G. Theodore, Miguel Priego de Wit

Geological Survey research 1978 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...
Authors
Water Resources Division U.S. Geological Survey

Paleomagnetic evidence for a Late Cretaceous deformation of the Great Valley Sequence, Sacramento Valley, California 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...
Authors
Edward A. Mankinen
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