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Tectonically Controlled Fan Delta and Submarine Fan Sedimentation of Late Miocene Age, Southern Temblor Range, California

Description: From introduction: The objectives of this report are to (1) document the stratigraphic framework of the Santa Margarita Formation and part of the Monterey Shale in the southern Temblor Range, (2) interpret the environments of deposition and depositional processes of the above units, and (3) evaluate the influence of tectonism on Santa Margarita sedimentation, with special attention given to testing the hypothesis of Berry and others (1968).
Date: 1989
Creator: Ryder, Robert T. & Thomson, Alan
Partner: UNT Libraries Government Documents Department

Jurassic (Bathonian and Callovian) Ammonites in Eastern Oregon and Western Idaho

Description: From abstract: Jurassic ammonites of late Bathonian to middle Callovian Age have been found in 12,000-13,000 feet (3,660-3,960 m) of strata exposed in the area near and south of Izee and Seneca in east-central Oregon. Ammonites of early Callovian Age and possibly also late Bathonian Age occur in several hundred feet of black shale exposed along Dennett Creek near Mineral, Idaho. Early Callovian ammonites also occur in similar black shale exposed on the Oregon side of Snake River Canyon about 32 miles (52 km) south of the northeast corner of Oregon.
Date: 1981
Creator: Imlay, Ralph W.
Partner: UNT Libraries Government Documents Department

Research in the Geysers-Clear Lake Geothermal Area, Northern California

Description: From abstract: The Geysers-Clear Lake geothermal area lies within the central belt of the Franciscan assemblage in northern California. The structure of this terrane is characterized by northeast-dipping imbricate thrust slices that have been warped and cut by steeply dipping strike-slip and normal faults. Introduction of magma into the crust beneath the Geysers-Clear Lake area can be related to eastsoutheast extension accompanying northward propagation of the San Andreas transform system between the Clear Lake region and Cape Mendocino within the last 3 million years. The initiation of strike-slip faulting during this time terminated subduction of elements of the Farallon plate beneath North America as strike-slip motion was taken up along the Pacific-North American plate boundary. The mechanism for magma generation appears to require a heat source in the mantle that mixed mantle-derived melts with various crustal rocks. These crustal rocks may have included the Franciscan central and coastal belts, ophiolite, Great Valley sequence, and possibly middle and late Tertiary rocks subducted before initiation of strike-slip faulting.
Date: 1981
Creator: McLaughlin, Robert J. & Donnelly-Nolan, Julie M.
Partner: UNT Libraries Government Documents Department

The Sorting and Deposition of Allochthonous Plant Material in a Modern Environment at Silwood Lake, Silwood Park, Berkshire, England

Description: Abstract: Quantitative statistical sampling of plant debris entombed within deltaic sediments of a Holocene fluviolacustrine environment at Silwood Lake, Berkshire, demonstrates that patterns of deposition exist that can be used to reconstruct the relative spatial distributions of species within the source vegetation.
Date: 1981
Creator: Spicer, Robert A.
Partner: UNT Libraries Government Documents Department

Tectonics of Southeastern Arizona

Description: From abstract: The part of Arizona south and east of Tucson is underlain by a wide assortment of deformed rocks, as well as by some major mineralized districts. A synthesis of the tectonic evolution of the region is offered in this report, which is based on older studies of mining districts and on more recent field studies by students and by the U.S. Geological Survey, augmented by field review and selective remapping of many key areas. Through this synthesis the rocks of the region are seen to have been deformed in response to diverse stresses, at various times, with an increasing degree of structural anisotropy of the rocks through time. Consequently, reactivated faults are common features, and segments of some of these faults record various kinds of movement, thereby providing unusual interpretive difficulties for many of the past local studies.
Date: 1981
Creator: Drewes, Harald D.
Partner: UNT Libraries Government Documents Department

Duration of Hydrothermal Activity at Steamboat Springs, Nevada, From Ages of Spatially Associated Volcanic Rocks

Description: Abstract: Steamboat Springs is a presently active equivalent of epithermal gold-silver ore-forming systems. Hot-spring sinter deposits contain small amounts of gold, silver, mercury, antimony, and arsenic. Hot-spring activity probably started before extrusion of the basaltic andesite of Steamboat Springs. Old sinter from the Steamboat Springs system occurs in gravels above and below the basaltic andesite. Intense hydrothermal alteration, including almost complete replacement by hydrothermal potassium-feldspar, has affected the basaltic andesite. Three plagioclase separates of differing potassium content from fresh basaltic andesite yielded potassium-argon ages of 2.52 to 2.55 m.y. Basaltic andesite almost completely replaced by potassium-feldspar yielded an age of 1.1 m.y. The source of energy for the thermal convection system is probably a large rhyolitic magma chamber that supplied the pumice and from which the rhyolite domes were emplaced. Sanidine and obsidian from four of the rhyolite domes yielded potassium-argon ages of 1.15 to 1.52 m.y. and obsidian from one of the northeastern domes yielded apparent ages of 2.97 and 3.03 m.y. The data indicate that hydrothermal activity has occurred at Steamboat Springs, possibly intermittently, for more than 2-1/2 m.y. These data agree with other radiogenic age studies indicating 1- and 2-m.y. lifetimes for the hydrothermal systems that generate epithermal gold-silver deposits.
Date: 1979
Creator: Silberman, M. L.; White, D. E.; Keith, T. E. C. & Dockter, R. D.
Location Info:
Partner: UNT Libraries Government Documents Department

The Lyon Station-Paulins Kill Nappe : the Frontal Structure of the Musconetcong Nappe System in Eastern Pennsylvania and New Jersey

Description: From abstract: Geologic and aeromagnetic data show that a major tectonic unit underlies rocks of the Musconetcong nappe in the Great Valley of eastern Pennsylvania and New Jersey. This structure, the Lyon Station-Paulins Kill nappe, can be traced from Lyon Station, Pa., at least to Branchville, N.J., a distance of about 120 km. The nappe has a core of Precambrian crystalline rocks as shown by an aeromagnetic anomaly that has the same signature as the outcropping Precambrian rocks of the Musconetcong nappe. This core extends at least 70 km east from Lyon Station to Bangor, Pa., the eastern limit of the aeromagnetic survey. This report details the frontal structure of this system.
Date: 1978
Creator: Drake, Avery Ala, Jr.
Partner: UNT Libraries Government Documents Department

Postglacial Volcanic Deposits at Mount Baker, Washington, and Potential Hazards From Future Eruptions

Description: Abstract: Eruptions and other geologic events at Mount Baker during the last 10,000 years have repeatedly affected adjacent areas, especially the valleys that head on the south and east sides of the volcano. Small volumes of tephra were erupted at least four times during the past 10,000 years. Future eruptions like these could cause as much as 35 centimeters of tephra to be deposited at sites 17 kilometers from the volcano, 15 centimeters of tephra to be deposited 29 kilometers from the volcano, and 5 centimeters, 44 kilometers from the volcano. Lava flows were erupted at least twice during the last 10,000 years and moved down two valleys. Future lava flows will not directly endanger people because lava typically moves so slowly that escape is possible. Hot pyroclastic flows evidently occurred during only one period and were confined to the Boulder Creek valley. Such flows can move at speeds of as much as 150 kilometers per hour and can bury valley floors under tens of meters of hot rock debris for at least 15 kilometers from the volcano. Large mudflows, most of which contain hydrothermally altered rock debris, originated at Mount Baker at least eight times during the last 10,000 years. The largest mudflow reached 29 kilometers or more down the valley of the Middle Fork Nooksack River, west of the volcano, about 6,000 years ago. Extensive masses of hydrothermally altered rock that are potentially unstable exist today near the summit of the volcano, especially in the Sherman Crater-Sherman Peak area. Avalanches of this material could be triggered by stream explosions, earthquakes, or eruptions, or may occur because of slow-acting forces or processes that gradually decrease stability. Large avalanches could move downslope at high speed and could grade downvalley into mudflows. Floods caused by rapid melting of snow and ice ...
Date: 1978
Creator: Hyde, Jack H. & Crandell, Dwight Raymond
Partner: UNT Libraries Government Documents Department

Paleozoic-Mesozoic Boundary in the Berry Creek Quadrangle, Northwestern Sierra Nevada, California

Description: Abstract: Structural and petrologic studies in the Berry Creek quadrangle at the north end of the western metamorphic belt of the Sierra Nevada have yielded new information that helps in distinguishing between the chemically similar Paleozoic and Mesozoic rocks. The distinguishing features are structural and textural and result from different degrees of deformation. Most Paleozoic rocks are strongly deformed and thoroughly recrystallized. Phenocrysts in metavolcanic rocks are granulated and drawn out into lenses that have sutured outlines. In contrast, the phenocrysts in the Mesozoic metavolcanic rocks show well-preserved straight crystal faces, are only slightly or not at all granulated, and contain fewer mineral inclusions than do those in the Paleozoic rocks. The groundmass in the Paleozoic rocks is recrystallized to a fairly coarse grained albite-epidote-amphibole-chlorite rock, whereas in the Mesozoic rocks the groundmass is a very fine grained feltlike mesh with only spotty occurrence of well-recrystallized finegrained albite-epidote-chlorite-actinolite rock. Primary minerals, such as augite, are locally preserved in the Mesozoic rocks but are altered to a mixture of amphibole, chlorite, and epidote in the Paleozoic rocks. In the contact aureoles of the plutons, and within the Big Bend fault zone, which crosses the area parallel to the structural trends, all rocks are thoroughly recrystallized and strongly deformed. Identification of the Paleozoic and Mesozoic rocks in these parts of the area was based on the continuity of the rock units in the field and on gradual changes in microscopic textures toward the plutons.
Date: 1977
Creator: Hietanen, Anna Martta
Partner: UNT Libraries Government Documents Department

Revisions of Ulmus and Zelkova in the Middle and Late Tertiary of Western North America

Description: Abstract: Examination of previously described and some undescribed leaves of Ulmus and Zelkova from the later Oligocene, Miocene, and Pliocene of western North America indicates that at least eight species of Ulmus and two species of Zelkova are represented. Three new species are described: Ulmus chaneyi, U. knowltoni, and Zelkova browni.
Date: 1977
Creator: Tanai, Toshimasa & Wolfe, Jack A.
Partner: UNT Libraries Government Documents Department

Stratigraphy and Microfaunas of the Oquirrh Group in the Southern East Tintic Mountains, Utah

Description: Abstract: The Oquirrh Group of Pennsylvanian and Permian age in the southern East Tintic Mountains, Utah, is more than 15,000 feet (4,572 m) thick and consists of an incomplete section of the West Canyon Limestone (Morrowan) 960 feet (293 m) thick, a nearly complete section of the Butterfield Peaks Formation (Atokan(?) and Des Moinesian) about 5,800 feet (1,768 m) thick, a complete section of the Bingham Mine Formation (Missourian) 3,200-3,400 feet thick (975-1,036 m), and a complete section of the newly named Furner Valley Limestone (Missourian to Wolfcampian) 5,000-6,000 feet (1,524-1,829 m) thick. The formations below the Furner Valley Limestone are generally similar to their counterparts in their type areas in the central and southern Oquirrh Mountains but are somewhat thinner and less arenaceous. The Furner Valley Limestone, more than 90 percent carbonate, is apparently unique. Strata of the same age in the Wasatch, Stansbury, Cedar, Hogup, and Promontory Mountains in Utah are all considerably arenaceous; in the southern Oquirrh Mountains in the upper plate of the Midas thrust fault they have been largely removed by erosion. The Oquirrh Group in the East Tintic Mountains is overlain by the Diamond Creek Sandstone; the latter, in turn, is overlain by the Park City Formation. No units lithologically resembling the Kirkman Limestone of the Wasatch Mountains are recognized. Fusulinids are common in the Butterfield Peaks and Bingham Mine Formations and are present throughout the Furner Valley Limestone. The faunas are comparable to those of the Oquirrh Group in the Oquirrh and Cedar Mountains to the west and in the Wasatch Mountains to the east.
Date: 1977
Creator: Morris, H. T.; Douglass, Raymond C. & Kopf, Rudolph W.
Partner: UNT Libraries Government Documents Department

Studies Related to the Charleston, South Carolina, Earthquake of 1886: a Preliminary Report

Description: From abstract: The seismic history of the southeastern United States is dominated by the 1886 earthquake near Charleston, S.C. An understanding of the specific source and the uniqueness of the neotectonic setting of this large earthquake is essential in order to properly assess seismic hazards in the southeastern United States. Such knowledge will also contribute to the fundamental understanding of intraplate earthquakes and will aid indirectly in deciphering the evolution of Atlantic-type continental margins. The 15 chapters in this volume report on the first stage of an ongoing multidisciplinary study of the Charleston earthquake of 1886.
Date: 1977
Creator: Rankin, Douglas W.
Partner: UNT Libraries Government Documents Department

Platinum Deposits of the Goodnews Bay District, Alaska

Description: From abstract: Platinum placers were discovered in 1926 in a small area south of Goodnews Bay, in southwestern Alaska. Beginning in 1927, the placers were worked for 7 years by small-scale mining methods; in later years dragline excavators and a dredge were utilized. These deposits are important, not only because they are of high grade but because they are the only commercial source of platinum metals in the United States. This report details the deposits in this district.
Date: 1976
Creator: Mertie, John Beaver, Jr.
Partner: UNT Libraries Government Documents Department

Stratigraphy and Geologic History of the Montana Group and Equivalent Rocks, Montana, Wyoming, and North and South Dakota

Description: From introduction: This is a progress report on regional stratigraphic and paleontologic studies of the Upper Cretaceous Montana Group and equivalent rocks in the northern part of the western interior of the United States. It presents preliminary data on the positions of strandlines during a 14-m.y. (million year) span of the Late Cretaceous as well as our interpretations of the geologic history of this period.
Date: 1973
Creator: Gill, James R. & Cobban, William Aubrey
Partner: UNT Libraries Government Documents Department

Contributions to Astrogeology, 1967-71

Description: From contributions of astrogeology: The principal goal of research in astrogeology is the solution of several cardinal problems of geology...The present volume is the first of a series of professional papers that will describe major results of research in astrogeology.
Date: 1972
Creator: Geological Survey (U.S.)
Partner: UNT Libraries Government Documents Department

Foraminifera From the Northern Olympic Peninsula, Washington

Description: From introduction: This report deals with the stratigraphic and ecologic significance of Foraminifera contained in a Tertiary sequence that crops out in the northern part of the Olympic Peninsula, Wash. (pl. 1). The work was done as a part of a program of geologic investigations for oil and gas possibilities conducted by the U.S. Geological Survey.
Date: unknown
Creator: Rau, Weldon W.
Partner: UNT Libraries Government Documents Department

Geology and Ore Deposits of the Picher Field, Oklahoma and Kansas

Description: From Purpose and Scope of Report: This report presents a detailed description of the ore deposits of the Picher field and all phases of geology having a bearing on their localization, origin, and the search for them. It is based mainly on work done by the U.S. Geological Survey, but it also incorporates pertinent data from published literature, especially from the outstanding work of George M. Fowler and associates, and some unpublished data obtained from the geologic staffs of the mining companies.
Date: 1970
Creator: McKnight, Edwin Thor & Fischer, Richard P.
Partner: UNT Libraries Government Documents Department

A Descriptive Catalog of Selected Aerial Photographs of Geologic Features in Areas Outside the United States

Description: From introduction: The U.S. Geological Survey has selected and assembled 67 sets of aerial photographs that illustrate a variety of geologic features in Antarctica, South and Central America, the southwest Pacific, Iran, Japan, the Arabian Peninsula, Pakistan, and mainland China. Contact prints of the photographs composing these sets are available for purchase. Sets of photographs of geologic features in the United States and Puerto Rico are listed in a separate catalog (Denny, C. S., and others, 1968, A descriptive catalog of selected aerial photographs of geologic features in the United States: U.S. Geol. Survey Prof. Paper 590).
Date: 1969
Creator: Warren, Charles R.; Schmidt, Dwight Lyman; Denny, Charles Storrow & Dale, William J.
Partner: UNT Libraries Government Documents Department

Geology of the Great Smoky Mountains National Park. Tennessee and North Carolina

Description: From Preface: "The present account summarizes the results of a long investigation of the rocks of the Great Smoky Mountains (1946-55) by geologists of the staff of the U.S. Geological Survey, in collaboration with those of the Tennessee Division of Geology. The technical details of this investigation have already been set forth at length in professional papers of the U.S. Geological Survey. The present account contains the gist of these findings about the rocks of the mountains, and is accompanied by a map and structure sections in which the surface and underground extent of the rocks are displayed."
Date: 1968
Creator: King, Philip Burke; Neuman, Robert B. & Hadley, Jarvis B.
Partner: UNT Libraries Government Documents Department

Geology of the Hot Sulphur Springs quadrangle, Grand County, Colorado

Description: Scope and Purpose of Work: The quadrangle was mapped as part of the U.S. Geological Survey program of classifying and evaluating lands in the Public Domain. Mineral rights for coal had been retained in parts or all of Tps. 2 and 3 N., Rs. 77, 78, and 79 W. These areas are in part underlain by sedimentary rocks of Late Cretaceous(?) and early Tertiary age (Middle Park Formation), and in North Park these rocks are called the Coalmont Formation and contain coal. The chief purpose of the work was to map and study any coal beds found and to make a detailed geologic map that can be used as part of a geological atlas of the United States.
Date: 1968
Creator: Izett, Glen Arthur
Partner: UNT Libraries Government Documents Department