Publications
Filter Total Items: 1155
Geologic studies in Alaska by the U.S. Geological Survey, 1992 Geologic studies in Alaska by the U.S. Geological Survey, 1992
This collection of 19 papers continues the annual series of U.S. Geological Survey reports on the geology of Alaska. The contributions, which include full-length Articles and shorter Geologic Notes, cover a broad range of topics including dune formation, stratigraphy, paleontology, isotopic dating, mineral resources, and tectonics. Articles, grouped under four regional headings, span...
530 Ma zircon age for ophiolite from the New England orogen: Oldest rocks known from eastern Australia 530 Ma zircon age for ophiolite from the New England orogen: Oldest rocks known from eastern Australia
New ion microprobe data provide constraints on the timing of formation of ophiolitic rocks in the New England tectonic collage in eastern Australia. Results for analyses of magmatic zircons from plagiogranite of the Weraerai terrane ophiolite at Upper Bingara give a 206pb/238|j ag e Qf 53Q ± 6 Ma (2a). This plagiogranite is the oldest rock from eastern Australia yet identified. Existing...
Authors
J.C. Aitchinson, T. R. Ireland, M. Clark Blake, P.G. Flood
Bristol Lake basin--a deep sedimentary basin along the Bristol-Danby trough, Mojave Desert Bristol Lake basin--a deep sedimentary basin along the Bristol-Danby trough, Mojave Desert
No abstract available.
Authors
R.C. Jachens, Keith A. Howard
Kinematic evidence for extensional unroofing of the Franciscan Complex along the Coast Range Fault, Northern Diablo Range, California Kinematic evidence for extensional unroofing of the Franciscan Complex along the Coast Range Fault, Northern Diablo Range, California
Franciscan metagraywacke immediately below the Del Puerto ophiolite, an outlier of the Coast Range ophiolite in the northern Diablo Range, was sheared during top‐to‐the‐east displacement on the Coast Range fault. This represents normal faulting and extensional offset. It was accompanied by attenuation of the Coast Range ophiolite and Great Valley sequence in the hanging wall along layer...
Authors
T.A. Harms, A. S. Jayko, M. Clark Blake
Incorporation and redistribution of locally derived lithic fragments within a pyroclastic flow Incorporation and redistribution of locally derived lithic fragments within a pyroclastic flow
The lower Miocene Peach Springs Tuff exposed in the Newberry Mountains, California, was deposited within a paleovalley trending S65°W. Exposures within the paleovalley contain lithic breccia intercalated with ash-rich ignimbrite. The clast assemblage of the lithic breccias matches the rock types of the paleovalley walls, and therefore the clasts were not derived from a distant eruptive...
Authors
D.C. Buesch
Regional view in the search for kuroko deposits of the Hokuroku District, Japan Regional view in the search for kuroko deposits of the Hokuroku District, Japan
No abstract available.
Authors
Donald A. Singer, Ryoichi Kouda
Predicting sizes of undiscovered mineral deposits; an example using mercury deposits in California Predicting sizes of undiscovered mineral deposits; an example using mercury deposits in California
A critical part of the exploration for mineral deposits or of quantitative mineral resource assessments is the estimation of how large undiscoveredeposits might be. Typically, this problem is addressed using grade and tonnage models in which a major source of variation in possible sizes is accounted for by the differences in types of deposits (Cox and Singer, 1986; Mosier and Page, 1988...
Authors
C. F. Chung, Donald A. Singer, W. David Menzie
National Earthquake Hazards Reduction Program, summaries of technical reports; Volume XXXIII National Earthquake Hazards Reduction Program, summaries of technical reports; Volume XXXIII
No abstract available.
Authors
Muriel L. Jacobson
A quantitative link among mineral deposit modeling, geoscience mapping, and exploration-resource assessment A quantitative link among mineral deposit modeling, geoscience mapping, and exploration-resource assessment
No abstract available.
Authors
C. F. Chung, C. W. Jefferson, D.A. Singer
A reinterpretation of the timing, position, and significance of part of the Sacramento Mountains detachment fault, southeastern California A reinterpretation of the timing, position, and significance of part of the Sacramento Mountains detachment fault, southeastern California
A contact previously considered to be part of the Sacramento Mountains detachment fault (SDF), exposed in the Sacramento Mountains metamorphic core complex, is reinterpreted as an unconformity between Tertiary rhyolite of Eagle Peak and cataclastically deformed crystalline lower-plate rocks. This reinterpretation is based on outcrop-scale topographic relief and the absence of deformation...
Authors
Carol Simpson, Janet Schweitzer, Keith A. Howard
The Marina District, San Francisco, California: Geology, history, and earthquake effects The Marina District, San Francisco, California: Geology, history, and earthquake effects
A northwest-trending valley in the bedrock surface is buried by firm Pleistocene bay clay, a dense Pleistocene sand layer, soft Holocene bay sediments, loose to dense Holocene beach and dune sands, and artificial fill that have an aggregate maximum thickness of about 90 m (300 ft). Artificial filling of a cove at the site of The Marina District proceeded gradually from the late 1860s to...
Authors
Manuel G. Bonilla