Publications
Filter Total Items: 1147
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
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
Attenuation of the Coast Range ophiolite by extensional faulting and nature of the Coast Range "thrust," California
The late Mesozoic Coast Range ophiolite and Great Valley sequence in California were juxtaposed against the Franciscan Complex during a long tectonic history that included imbricate thrust faulting, low‐angle detachment, and high‐angle reverse faulting. Many low‐angle faults previously mapped as thrusts invariably juxtapose younger over older rocks, suggesting a normal sense of offset. We infer th
Authors
A. S. Jayko, M. Clark Blake, Tekla Harms
Remagnetization of the Coast Range Ophiolite and Lower Part of the Great Valley Sequence in Northern California and Southwest Oregon
Overprinted magnetizations have been found at four localities in the Middle Jurassic Coast Range ophiolite and the overlying Upper Jurassic and Lower Cretaceous Great Valley sequence in northern California and at one locality in the partially correlative Lower Cretaceous Days Creek Formation in southwest Oregon. At Del Puerto Canyon, on the east side of the Diablo Range, a pilot study of the upper
Authors
L.S. Frei, M. Clark Blake
Geologic terranes of coastal northern California and southern Oregon
No abstract available.
Authors
A. S. Jayko, M. Clark Blake