Publications
Publications from the staff of the Geology, Minerals, Energy, and Geophysics Science Center
Filter Total Items: 2354
Geologic map and structure sections of the Loma Prieta 7 1/2' quadrangle, Santa Clara and Santa Cruz Counties, California
No abstract available.
Authors
Robert J. McLaughlin, Joseph C. Clark, Earl E. Brabb
Vitrinite reflectance and illite crystallinity, Franciscan central belt and Yolla Bolly terrane, northern California
No abstract available.
Authors
M. B. Underwood, R.H. Strong, M. C. Blake
Climate and ephemeral-stream processes: Twentieth-century geomorphology and alluvial stratigraphy of the Little Colorado River, Arizona
During the first 40 years of the twentieth century, erosion was the dominant geomorphic process affecting the morphology of the Little Colorado River channel. The discharge regimen was one of frequent large floods and high annual discharge that created a wide sandy channel free of vegetation. In the 1940s and early 1950s, average annual precipitation declined, reducing annual discharge to about 57
Authors
Richard Hereford
Mineral resources of the Devil's Garden Lava Bed, Squaw Ridge Lava Bed, and Four Craters Lava Bed Wilderness Study Areas, Lake County, Oregon
No abstract available.
Authors
William J. Keith, Harley D. King, Mark E. Gettings, Fredrick L. Johnson
Reconnaissance geologic map of the Pilot Creek Quadrangle, Humboldt and Trinity counties, California
No abstract available.
Authors
K. R. Aalto, William Porter Irwin, H.M. Kelsey
Crustal extension along a rooted system of imbricate low-angle faults: Colorado River extensional corridor, California and Arizona
The upper 10 to 15 km of crystalline crust in the 100-km-wide Colorado River extensional corridor of mid-Tertiary age underwent extension along an imbricate system of gently dipping normal faults. Detachment faults cut gently down-section eastward in the direction of tectonic transport from a headwall breakaway, best expressed in the Old Woman Mountains, California. Successively higher and more di
Authors
Keith A. Howard, B.E. John
Metamorphic core complexes, Mesozoic ductile thrusts, and Cenozoic detachments: Old Woman Mountains: Chemehuevi Mountains transect, California and Arizona
No abstract available.
Authors
Keith A. Howard, B.E. John, C. F. Miller
Comment and reply on "Correlation of the Peach Springs Tuff, a large-volume Miocene ignimbrite sheet in California and Arizona"
No abstract available.
Authors
S.K. Mittwede, A. F. Glazner, Keith A. Howard, D. M. Miller
Lamoille Canyon nappe in the Ruby Mountains metamorphic core complex, Nevada
No abstract available.
Authors
Keith A. Howard
In search of the Abrams post office, Trinity County
An understanding of earth history depends in part on stratigraphy, a division of geology in which the distinctive features of natural units or formations of layered rocks are studied and described and names are assigned to them. The procedures for describing and naming rock units in a uniform way are incorporated in documents known as stratigraphic codes. The North American Stratigraphic Code (198
Authors
Marvin A. Lanphere, William P. Irwin
Thermal maturity of tectonostratigraphic terranes within the Franciscan Complex, California
Indicators of organic metamorphism provide valuable tools for analyzing the thermal history of tectonostratigraphic terranes. Paleotemperature estimates derived from vitrinite reflectance, for example, are more precise than values based upon inorganic mineral assemblages in low‐grade rocks. Isothermal geometries must be interpreted within the context of structural and stratigraphic data, but, by d
Authors
M. B. Underwood, M. Clark Blake, D. G. Howell
Tectonostratigraphic terranes of the Croissilles Harbour region, South Island, New Zealand
The boundary between Hokonui and Te Anau assemblages is flanked by a broad (10–20 km) zone of imbricated slabs of late Paleozoic and Mesozoic lithostratigraphic terranes. Five terranes are mapped, three of predominantly sedimentary character (Dun Mountain‐Maitai, Rai, Pelorus) are separated by two consisting of ophiolitic melange (Patuki, Croisilles). A regional stratigraphy is mapped within the L
Authors
C. A. Landis, M. Clark Blake