Publications
Publications from the staff of the Geology, Minerals, Energy, and Geophysics Science Center
Filter Total Items: 2350
Crustal studies using magnetic data
The magnetic method plays an important role in mineral, petroleum, and geothermal exploration. It also has made important contributions to geologic mapping, structural geology, and plate-tectonic theory. In particular, magnetic measurements using aircraft provide a relatively inexpensive way to trace magnetic rock units beneath covered areas, to reveal the shape of subsurface magnetic bodies, and
Authors
Richard J. Blakely, G. Connard
Isostatic residual gravity and crustal geology of the United States
A new isostatic residual gravity map of the conterminous United States presents continent-wide gravity data in a form that can be readily used, with geologic information and other geophysical data, in studies of the composition and structure of the continental crust. This map was produced from the gridded gravity data on which the recently released Gravity Anomaly Map of the United States is based
Authors
Robert C. Jachens, Robert W. Simpson, Richard J. Blakely, Richard W. Saltus
Evolution of the western part of the Coast plutonic–metamorphic complex, South-Eastern Alaska, USA: A summary
The western Cordillera of North America extends for over 6000 km from the tip of Baja California to the Alaska Range. It includes a wide variety of metamorphic and plutonic terrains, but none is more spectacular scenically or geologically than the Coast plutonic-metamorphic complex (Brew & Ford 1984) of western Canada and south-eastern Alaska. This report briefly describes the evolution of the wes
Authors
David A. Brew, A. B. Ford, G. R. Himmelberg
Geologic map and structure sections of the Laurel 7-1/2ʹ quadrangle, Santa Clara and Santa Cruz Counties, California
No abstract available.
Authors
J. C. Clark, E. E. Brabb, R. J. McLaughlin
Deformation of the Eastern Franciscan Belt, northern California
The late Jurassic and Cretaceous Eastern Franciscan belt of the northern California Coast Range consists of two multiply deformed, blueschist-facies terranes; the Pickett Peak and Yolla Bolly terranes. Four deformations have been recognized in the Pickett Peak terrane, and three in the Yolla Bolly terrane. The earliest recognized penetrative fabric, D1, occurs only in the Pickett Peak terrane. The
Authors
A. S. Jayko, M. C. Blake
The style of late Cenozoic deformation at the eastern front of the California Coast Ranges
The 1983 Coalinga earthquake occurred at the eastern boundary of the California Coast Ranges in response to northeast directed thrusting. Such movements over the past 2 Ma have produced Coalinga anticline by folding above the blind eastern tip of the Coalinga thrust zone. The 600-km length of the Coast Ranges boundary shares a common structural setting that involves westward upturn of Cenozoic and
Authors
C. M. Wentworth, M.D. Zoback
New evidence for polyphase metamorphism of glaucophane schist and eclogite exotic blocks in the Franciscan Complex, California and Oregon
The early metamorphic history of high-grade exotic blocks in the Franciscan Complex may be more complicated than previously supposed. The different assemblages of high-grade glaucophane schists, eclogite, amphibolite and hornblende schist are commonly considered to have formed at the same time from essentially unmetamorphosed oceanic crust. However, new textural and mineralogical data presented he
Authors
Diane E. Moore, M. C. Blake
Average topography, isostatic residual gravity, and aeromagnetic maps of the Parkfield region, California
No abstract available.
Authors
Robert W. Simpson, R.C. Jachens, Carl M. Wentworth
Borax in the supraglacial moraine of the Lewis Cliff, Buckley Island quadrangle--first Antarctic occurrence
During the 1987-1988 austral summer field season, membersof the south party of the antarctic search for meteorites south-ern team* working in the Lewis Cliff/Colbert Hills region dis-covered several areas of unusual mineralization within theLewis Cliff ice tongue and its associated moraine field (figure1). The Lewis Cliff ice tongue (84°15'S 161°25'E) is a meteorite-stranding surface of ablating b
Authors
J. J. Fitzpatrick, D.R. Muhs
Uranium-series ages, faunal correlations and tectonic deformation of marine terraces within the Agua Blanca fault zone at Punta Banda, northern Baja California, Mexico
No abstract available.
Authors
T. K. Rockwell, D.R. Muhs, G. L. Kennedy, M.E. Hatch, S.M. Wilson, R.E. Klinger
Oligocene and Miocene paleogeography of central California and displacement along the San Andreas fault
Recently completed sedimentologic and petrologic studies of Oligocene and Miocene strata in the Temblor Range (San Joaquin basin) and Santa Cruz Mountains (La Honda basin) permit detailed reconstructions of paleogeography, as well as new estimates of displacement along the San Andreas fault. During the Oligocene and Miocene, the San Joaquin and La Honda basins were contiguous. The southwestern mar
Authors
S.A. Graham, Richard G. Stanley, J. V. Bent, J. B. Carter