Publications
Publications from the staff of the Geology, Minerals, Energy, and Geophysics Science Center
Filter Total Items: 2354
Sedimentology of the Upper Devonian to Lower Mississippian(?) Kanayut Conglomerate in the vicinity of the Trans-Alaska Pipeline, Brooks Range, Alaska
No abstract available.
Authors
Thomas E. Moore, T. H. Nilsen, W. P. Brosge
The crustal structure of the Wrangellia Terrane along the East Glenn Highway, eastern‐southern Alaska
Recently acquired seismic refraction data from eastern‐southern Alaska provide new information on the structure and composition of the Wrangellia and adjacent terranes. The data comprise a 160‐km‐long refraction profile along the East Glenn (Tok‐Cutoff) Highway that was collected as part of the U.S. Geological Survey's multidisciplinary Trans‐Alaska Crustal Transect program. The upper 3 km of the
Authors
E.B. Goodwin, Gary S. Fuis, Warren J. Nokleberg, E. L. Ambos
Hydrothermal discharge zones beneath massive sulfide deposits mapped in the Oman ophiolite
The area in the Oman ophiolite containing the volcanic-hosted Bayda and Aarja massive sulfide deposits exposes a cross section of ocean crust and reveals to an unprecedented extent the fossil zones of hydrothermal upwelling that fed these sea-floor deposits. The fossil discharge zones are elongate areas of alteration and mineralization characterized by numerous small (metres to tens of metres in l
Authors
R.M. Haymon, Randolph A. Koski, M. J. Abrams
Geochemistry and occurrence of selenium: An overview
Selenium (Se) is both beneficial and toxic to animals, plants, and humans. Consequently, it is imperative to know its concentration in the environment and to understand the processes controlling its distribution. Determinations of Se concentrations in a variety of materials indicate that Se is widely distributed throughout the environment. The processes responsible for its distribution include vol
Authors
James M. McNeal, Laurie S. Balistrieri
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