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Frederic H. Wilson

Publications and source records attributed to Frederic H. Wilson.

At least 91 records · Page 5Linked to original sources
USGS1987

The Alaska Mineral Resource Assessment Program: Background information to accompany folio of geologic and mineral resource maps of the Circle quadrangle, Alaska

The geology, geochemistry, geophysics, and Landsat imagery of the Circle quadrangle were investigated by an interdisciplinary research team for the purpose of assessing the mineral potential of the area. The quadrangle covers approximately 15,765 km 2 in east-central Alaska; most of it is included in the mountainous Yukon-Tanana Upland physiographic division, but the northernmost part is in the low-lying Yukon Flats section. The Circle mining district, in the east-central part of the quadrangle, has been a major producing area of placer gold since its discovery in 1893. For descriptive purposes, the Circle quadrangle is divided into three areas: the northwest Circle quadrangle, the area north of the Tintina fault zone, and the area south of the Tintina fault zone. The Tintina fault zone extends northwesterly through the northern part of the quadrangle. The northwest Circle quadrangle contains mostly folded and faulted, slightly metamorphosed sedimentary rocks that are intruded by Tertiary granitic plutons. In the northern part of the area north of the Tintina fault zone (Little Crazy Mountains and northern east Crazy Mountains), the rocks consist primarily of the gabbro and basalt of the Circle Volcanics and minor associated chert, graywacke, and limestone. Elsewhere in this area (south of the Circle Volcanics and in the western Crazy Mountains), the rocks are mostly slightly metamorphosed Paleozoic sedimentary rocks that have been folded and faulted. Rocks in the largest part of the quadrangle, the area south of the Tintina fault zone, consist largely of pelitic rocks that are regionally metamorphosed to greenschist and amphibolite facies. Felsic plutons, mostly Tertiary in age, occur throughout the area. The metamorphic rocks are separated from sedimentary rocks on the northwest by thrust faulting. The aeromagnetic and gravity data show clear differences between the areas north and south of the Tintina fault zone. The metamorphic terrane to the south has low overall gravity and local gravity lows over exposed granitic plutons. It is hypothesized that magnetic chlorite schist infolded with nonmagnetic quartzite and schist account for east-northeast-trending magnetic highs that approximately parallel the regional strike of the most prominent foliation in the metamorphic rocks. North of the Tintina fault zone, the Circle Volcanics are characterized by high gravity and east-west-trending magnetic highs. The Tintina fault zone has an intense magnetic high near the western margin of the Circle quadrangle overlying the magnetic granodiorite of the Victoria Mountain pluton. A magnetic high near Circle Hot Springs is less intense, but broader, and could reflect a buried magnetic pluton similar to that of the Victoria Mountain pluton. Computer-enhanced Landsat images of the Circle quadrangle show trends and patterns of concentrations of linear features. Features trending northeast-southwest predominate throughout the quadrangle; northwest-southeast-trending linear features are found mostly south of the Tintina fault zone. High concentrations of linear features were not found to correspond to areas of known mineralization in any consistent or significant way that could presently be used in locating areas of mineralization. Geochemical and mineralogical studies of stream sediment and heavy-mineral concentrates from the Circle quadrangle identify areas of anomalous concentrations of metallic elements, including gold, silver, tin, tungsten, lead, antimony, zinc, thorium, uranium, and beryllium. The data delineate areas of known mineral occurrences and areas that may contain undiscovered mineral resources. To date, placer gold has been the only significant metallic mineral resource from the Circle quadrangle, but the general geologic setting, especially the presence of post-orogenic plutons, is similar to that of regions that contain tin greisen deposits, tungsten skarn deposits, lode gold deposits in metasedimentary rocks, and uranium vein deposits. Six areas or tracts were identified in which such deposits might occur, and two more tracts were delineated as possible for the occurrence of shale-hosted Lead-zinc deposits. The discovery of two diamonds in the gravels of Cooked Creek point to the slight possibility of finding placer or lode diamond deposits. Although most of the past and present gold mining has taken place in four areas in the quadrangle, a sedimentary basin near the town of Central was identified as possibly containing buried placer gold deposits or sedimentary uranium deposits.

Alaska↗
USGS1987

Tables showing analyses of semiquantitative spectrometry and atomic-absorption spectrophotometry of rock samples collected in the Ugashik, Bristol Bay, and western part of the Karluk quadrangles, Alaska

The accompanying tables list chemical analyses of 337 rock samples that were collected in 1979, 1980, and 1981 in conjunction with geologic mapping in the Ugashik, Bristol Bay, and part of Karluk quadrangles. This work was conducted under the auspices of the Alaska Mineral Resource Assessment Program (AMRAP). This report is to accompany Wilson and O'Leary (1986) which inadvertently is missing most of the data tables listed here. Together the two reports contain the complete data from all samples collected for the Ugashik AMRAP.

Alaska↗
USGS1986

Later Paleozoic and Early Jurassic fossil ages from the McHugh Complex: A section in Geologic studies in Alaska by the U.S. Geological Survey during 1985 Circular 978

Late Mississippian through Early Pennsylvanian and Early Jurassic microfossils were collected from the type locality of the McHugh Complex (Clark, 1973) along the Seward Highway southeast of Anchorage (fig. 36). Radiolarians collected indicate that same of the oceanic rocks in the McHugh Complex are Early Jurassic in age. Conodonts extracted from a conglomerate clast are of Late Mississippian through earliest Pennsylvanian age. The conodont-bearing clast may have been derived from the Strelna Fornation.

Alaska↗
USGS1986

Maps and tables showing data and analyses of semiquantitative emmission spectrometry and atomic-absorption spectrophotometry of rock samples, Ugashik, Bristol Bay, and part of Karluk quadrangles, Alaska

The accompanying maps and tables show analytical data and data analyses from rock samples collected in conjunction with geologic mapping in the Ugashik, Bristol Bay and western Karluck quadrangles from 1979 through 1981. This work was conducted under the auspices of the Alaska Mineral Resource Assessment Program (AMRAP). A total of 337 samples were collected for analysis, primarily in areas of surficial alteration. The sample locations are shown on sheet 1: they are concentrated along the Pacific Ocean side of the area because the Bristol Bay lowlands part of the map is predominantly unconsolidated Quaternary deposits. Sample collection was by the following people, with their respective two letter identifying code shown in parentheses: W.H. Allaway (AY), J.E. Case (CE), D.P. Cox (CX), R.L. Detterman, (DT), T.G. Theodore (MK), F.H. Wilson (WS), and M.E. Yount (YB).

Alaska↗
USGS1985

Review of radiometric data from the Yukon crystalline terrane, Alaska and Yukon Territory

The results of more than 20 years of geochronological studies in the Yukon Crystalline Terrane in east-central Alaska and the western Yukon Territory suggest at least six igneous and thermal (metamorphic?) events. Plutonism during Mississippian, Early Jurassic, mid-Cretaceous, Late Cretaceous, and early Tertiary times is indicated. Evidence also indicates that Mississippian, Early Jurassic, late Early Cretaceous, and late Cretaceous thermal (metamorphic?) events have affected parts of the terrane. The western part of the terrane was affected by a significant regional metamorphic event in late Early Cretaceous time, followed by a terrane-wide mid-Cretaceous plutonic event. The pattern of K–Ar ages allows division of the terrane into domains, bounded by northeast-trending lineaments.

Alaska, Yukon Territory↗
USGS1985

The Meshik Arc: An eocene to earliest miocene magmatic arc on the Alaska Peninsula

The Meshik arc is herein defined to include Eocene to earliest Miocene volcanic and hypabyssal rocks and the associated Meshik and Stepovak Formations of the central Alaska Peninsula. Igneous rocks range from basalt to dacite and yielded K-Ar ages of 48 to 22 m.y. The Meshik arc is oriented along the trend of the Alaska Peninsula, subparallel to the present-day Aleutian arc. Rocks of the Meshik arc are emplaced on Cenozoic, Mesozoic, and older clastic sedimentary rocks of the Alaska Peninsula terrane. Tectonic interpretation suggests: a) the arc represents a relatively stationary period in the otherwise mobile migration of the Alaska Peninsula terrane, b) subduction was an important process along the Alaska Peninsula during Tertiary time, and c) most migration of the Alaska Peninsula terrane since Cretaceous time took place in Paleocene and middle Miocene time.

Alaska↗
USGS1985

Digital image processing techniques for detecting surface alteration - An application on the Alaska Peninsula: A section in The United States Geological Survey in Alaska: Accomplishments during 1983

The tectonic evolution of the Alaska Peninsula makes it a likely area for the discovery of significant mineral deposits. However, because of problems associated with remoteness and poor weather, little detailed mineral exploration work has been carried on there. This study focuses on using Landsat multispectral scanner data for the Port Moller, Stepovak Bay, and Simeon of Island Quadrangles to detect surface alteration, probably limonitic (iron oxide staining) and(or) argillic (secondary clay minerals) in character, that could be indicative of mineral deposits. The techniques used here are useful for mapping deposits that have exposed surface alteration of at least an hectare, the approximate spatial resolution of the Landsat data. Virtually cloud-free Landsat coverage was used, but to be detected, the alteration area must also be unobscured by vegetation. Not all mineral deposits will be associated with surface alteration, and not all areas of surface alteration will have valuable mineral deposits.

Alaska↗
USGS1985

Eruption in an ice-filled caldera, Mount Veniaminof, Alaska Peninsula: A section in The United States Geological Survey in Alaska: Accomplishments during 1983

The more prominent of the two visible intracaldera cones of Mount Veniaminof went into eruption in early June 1983 and continued until early April 1984. Veniaminof is a 2,507-m-high composite cone having an 8 x 11-km summit caldera which formed 3,300-3,700 yr B.P. (Miller and Smith, 1977). The active 1.6x1.2-km cone protrudes 200 m through the glacial ice filling the caldera; it lies in a 60-m-long belt of cinder cones that is transverse to the trend of the Aleutian arc (fig. 44).

Alaska↗
USGS1985

Newly discovered Holocene volcanic vents, Port Moller and Stepovak Bay quadrangles, Alaska Peninsula: A section in The United States Geological Survey in Alaska: Accomplishments during 1983

Reconnaissance mapping in 1982-83 suggests previously unreported Holocene volcanic activity in the area 14-24 km southwest of Kupreanof Volcano (fig. 45). One young volcanic vent has been observed along the divide between Stepovak Bay and Bear Lake, and the locations of two others are inferred from the position of morphologically young lava flows mapped in valleys draining into Clark Bay, Grub Gulch, and Ramsey Bay. Other morphologically young flows extending northwest from the divide are evident on aerial photographs.

Alaska↗
USGS1985

Preliminary description of a Miocene zone of structural complexity, Port Moller and Stepovak Bay quadrangles, Alaska: A section in The United States Geological Survey in Alaska: Accomplishments during 1983

A zone of structural disruption and complexity along the Pacific coast margin of the Alaska Peninsula (fig. 41) may be related to the Alaska Peninsula and the Chugach terrane boundary. The best exposure of this zone is located on the east shore of Humpback Bay (figs. 42, 43; also Burk, 1965, pl. 8, fig. 4); other exposures are located on the east side of Ivanof Bay, the north and south sides of Lefthand Bay, and in other coastal localities in the area. In some places, such as on the Kupreanof Peninsula, it is not recognized. This zone may extend discontinuously for 110-160 km along the coast; the width of the zone varies from 0.5 to 1 km. Our current data and tentative interpretations are described here, pending completion of additional field research, laboratory, and office studies.

Alaska↗
USGS1985

Processing of Landsat imagery to map surface mineral alteration on the Alaska Peninsula: A section in USGS research on mineral resources, 1985 program and abstracts

Landsat images were digitally processed to facilitate assessment of the mineral resources of the Port Moller, Stepovak Bay, and Simeonof Island 1:250,000 quadrangles. Field mapping and assessment of these quadrangles were begun in 1983 as part of the Alaska Mineral Resource Assessment Program (AMRAP). It was quickly realized that time and budget constraints would limit mapping coverage. Therefore, at the suggestion of Roger Ashley, we used existing Landsat multispectral scanner imagery to aid in locating surface alteration, which could be field checked or related to stream-sediment or hand-sample geochemical data.

Circular↗