Geology topics
Frederic H. Wilson
Publications and source records attributed to Frederic H. Wilson.
Generalized geologic map of the Ugashik, Bristol Bay and part of Karluk quadrangles, Alaska
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Geochronology, geochemistry, and tectonic environment of porphyry mineralization in the central Alaska Peninsula
Porphyry type sulfide systems on the central Alaska Peninsula occupy a transition zone between the Aleutian island magmatic arc and the continental magmatic arc of southern Alaska. Mineralization occurs associated with early and late Tertiary magmatic centers emplaced through a thick section of Mesozoic continental margin clastic sedimentary rocks. The systems are of the molybdenum-rich as opposed to gold-rich type and have anomalous tungsten, bismuth, and tin, attributes of continental-margin deposits, yet gravity data suggest that at least part of the study area is underlain by oceanic or transitional crust. Potassium-argon age determinations indicate a variable time span of up to 2 million years between emplacement and mineralization in a sulfide system with mineralization usually followed by postmineral intrusive events. Finally, mineralization in the study area occurred at many times during the time span of igneous activity and should be an expected stage in the history of a subduction related magmatic center.
Apparent episodicity of magmatic activity based on radiometric age determination: A section in The United States Geological Survey in Alaska: Accomplishments during 1980
Results of recent potassium-argon age studies in the Chignik region, Alaska, (Wilson, 1980; Wilson and others, 1982) have suggested a distinct episodicity in igneous activity during Tertiary time. To date work on the Aleutian magmatic arc indicates that plutonic activity took place along the present outer Pacific margin and in the northern Alaska-Aleutian Range batholith (Reed and Lanphere, 1973; Kienle and Turner, 1976; DeLong and others, 1978) in latest Cretaceous and earliest Tertiary time (70-58 m.y.) and was followed by a hiatus lasting until late Eocene ( 45 m.y~) time. Late Eocene to earliest Miocene ( 45-20 m.y.) magmatic activity was followed by a middle Miocene hiatus (10 m.y.). Since that time, magmatic activity in the Aleutian arc has been continuous.
Aeromagnetic survey of the Chignik and Sutwik Island quadrangles: A section in The United States Geological Survey in Alaska: Accomplishments during 1980
The recently completed aeromagnetic survey of the Chignik and Sutwik Island quadrangles, on the Alaska Peninsula, is one of the most detailed systematic surveys ever made across a modern "volcanic arc" setting where both Holocene volcanic edifices and older volcanic centers occur (fig. 54).
Preliminary results of potassium-argon age determinations from the Ugashik quadrangle, Alaska Peninsula: A section in The United States Geological Survey in Alaska: Accomplishments during 1980
Early and preliminary results of potassiumargon dating work on samples from 12 sites in the Ugashik quadrangle indicate a continuation of the geologic trends seen in the Chignik and Sutwik Island quadrangles to the south (Wilson, 1980). Tertiary volcanic and hypabyssal rocks apparently fall into two age groups: early Tertiary-late Eocene to earliest Miocene and late Tertiary and Quaternary-late Miocene to Holocene (fig. 53).
Reconnaissance geochemical studies in the Bristol Bay, Ugashik, and Karluk quadrangles, Alaska: A section in The United States Geological Survey in Alaska: Accomplishments during 1980
Geochemical reconnaissance studies in the Bristol Bay, Ugashik, and Karluk quadrangles were completed with collection and analyses of more than 1,200 stream-sediment and heavy mineral-concentrate samples during 1979 and 1980. At least two areas of possible metallic mineral occurrence have been delineated by results of the analyses, geologic fieldwork, and data provided by Bear Creek Mining Company.
Radiometric age file for Alaska: A section in The United States Geological Survey in Alaska: Accomplishments during 1980
The Alaska radiometric age file of the Branch of Alaskan Geology is a computer-based compilation of radiometric dates from the state of Alaska and the western parts of the Yukon Territory and British Columbia. More than 1800 age determinations from over 250 references have been entered in the file. References date back to 1958 and include both published and unpublished sources. The file is the outgrowth of an original radiometric age file compiled by Don Grybeck and students at the University of Alaska-Fairbanks (Turner and others, 1975).
Map and tables showing preliminary results of K-Ar age studies in the Ugashik quadrangle, Alaska Peninsula
No abstract available.
The Alaskan Mineral Resource Assessment Program; background information to accompany folio of geologic and resources maps of the Chignik and Sutwik Island quadrangles, Alaska
The Chignik and Sutwik Island quadrangles (1:250,000) are a part of the Alaska Peninsula in southwestern Alaska. This circular and a companion folio of maps represent results of integrated field and laboratory studies by an interdisciplinary team on geology, geophysics, geochemistry, mineral resources, geochronology, and energy resources to provide a modern assessment of the mineral and energy resources of the quadrangles. The maps contain descriptive text, explanatory material, tables and diagrams, and pertinent references. This circular provides the background data for the mineral and energy resource assessment and integrates the component maps. A comprehensive bibliography cites both specific and general references relevant to the geology and resources of the quadrangles.
Quaternary geologic map of the Chignik and Sutwik Island quadrangles, Alaska
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Maps showing aeromagnetic survey and geologic interpretation of the Chignik and Sutwik Island quadrangles, Alaska
An aeromagnetic survey over part of the Chignik and Sutwik Island quadrangles, on the southern Alaska Peninsula, was flown in 1977 as part of the Alaska mineral resource assessment program (AMRAP). Maps at scales 1:250,000 and 1:63,360 have been released on open-file (U.s. Geological Survey, 1978a, 1978b). This report includes the aeromagnetic map superimposed on the topographic base (sheet 1) and an interpretation map superimposed on the topographic and simplified geologic base (sheet 2). This discussion provides an interpretation of the aeromagnetic data with respect to regional geology, occurrence of ore deposits and prospects, and potential oil and gas resources. The survey was flown along northwest-southeast lines, spaced about 1.6 km apart, at a nominal elevation of about 300 m above the land surface. A proton-precession magnetometer was used for the survey, and the resulting digital data were computer contoured at intervals of 10 and 50 gammas (sheet 1). The International Geomagnetic Reference Field (IGRF) of 1965, updated to 1977, was removed from the total field data.
Map and tables showing geochronology and whole-rock geochemistry, Chignik and Sutwik Island quadrangles, Alaska
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Map and table showing radiometric ages of rocks in the Aleutian Islands and Alaska Peninsula
No abstract available.
Map and tables showing preliminary results of potassium-argon age studies in the Circle Quadrangle, Alaska, with a compilation of earlier dating work
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