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Mafic and Ultramafic Xenoliths from Volcanic Rocks of the Western United States

Description: From abstract: Mafic and ultramafic xenoliths in the Western United States are present in volcanic rocks ranging from lamprophyric to dacitic in composition and are found in every major tectonic province from the Coast ranges from California to the Great Plains. Xenoliths from 68 localities are described here, but new localities are being discovered, and much remain to be learned about their distribution with respect to the tectonic and geophysical framework of the Western United States.
Date: 1988
Creator: Wilshire, Howard Gordon; Meyer, C. E.; Nakata, John K.; Calk, L. C.; Shervais, John W.; Nielson, J. E. et al.
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Partner: UNT Libraries Government Documents Department

Quaternary Movement Along the La Jencia Fault, Central New Mexico

Description: From abstract: The La Jencia fault is a recently reactivated late Cenozoic basin margin structure of major proportions that forms the western margin of the Rio Grande rift, which borders the eastern sides of the northern Magdalena Mountains and the southern Bear Mountains in central New Mexico. Stratigraphic throw on the fault has not been determined, but Precambrian rocks of the Magdalena Mountains are uplifted a minimum of 800 m (meters) above the adjacent basin floor, below which lie a thick section of upper Cenozoic basin-fill deposits. Most of the implied displacement is probably Neogene in age.
Date: 1988
Creator: Machette, Michael N.
Partner: UNT Libraries Government Documents Department

Geology of the southern Guadalupe Mountains, Texas

Description: From Abstract: "This report deals with an area of 425 square miles in the western part of Texas, immediately south of the New Mexico line. The report describes the geology of the area, that is, the nature of its rocks, tectonics, and surface features, and the evidence that they give as to the evolution of the area through geologic time. Incidental reference is made to the geology of surrounding regions in order to place the area in its environment."
Date: 1948
Creator: King, Philip B.
Partner: UNT Libraries Government Documents Department

Pre-Cambrian Rocks of the Lake Superior Region: A Review of Newly Discovered Geologic Features, with a Revised Geologic Map

Description: From abstract: Detailed knowledge of the geology of the pre-Cambrian rocks of the Lake Superior region has been greatly augmented since the publication of Monograph 52 by the United States Geological Survey in 1911. The authors have attempted in the present report to assemble as much of this new information as possible, and to give the reader a birdseye view of the geology as seen in the light of all studies made there up to the present time. Detailed descriptions are not presented, and the emphasis is placed upon the major problems of correlation. A revised map of the region, with cross sections, accompanies the report, bringing up to date a knowledge of the areal geology of the region, which otherwise could be gained only by consulting some 150 maps contained in almost as many separate local reports, many of which are unpublished.
Date: 1935
Creator: Leith, C. K.; Lund, Richard Jacob & Leith, Andrew
Partner: UNT Libraries Government Documents Department

The Flora of the New Albany Shale: Part 1. Diichnia Kentuckiensis, a New Representative of the Calamopityeae

Description: Abstract: A new genus of the Cycadofilicales, Diichnia, is described from the New Albany shale, of late Devonian age, in central Kentucky. The one known species, which is based on stem material showing internal structure, belongs in the family Calamopityeae. Foundation for the generic segregation is seen in the double leaf truce of the genotype, D. kentuckiensis, in contrast with the originally single trace in other known representatives of the family.
Date: 1936
Creator: Read, Charles B.
Partner: UNT Libraries Government Documents Department

Geologic History of the Yosemite Valley

Description: The principal result of the investigations upon which this report is based is the determination within narrow limits of the preglacial depth of the Yosemite Valley and of other facts concerning its preglacial development which permit fairly definite estimates of the proportionate shares of work performed by stream and by glacier. The investigations comprise a detailed survey of the glacial and geomorphologic features of the Yosemite region and an equally intensive study of its rock formations, supplemented by reconnaissance work of both kinds in adjoining parts of the Sierra Nevada.
Date: 1930
Creator: Matthes, Franc╠žois E.
Partner: UNT Libraries Government Documents Department

Geology and Ore Deposits of the Park City District, Utah

Description: From introduction: This survey was the first systematic work undertaken in this geologic province since the Geological Exploration of the Fortieth Parallel, in 1869, and was the first detailed geologic examination of a wide area in the Wasatch Range. Hence, an unusual amount of general geologic work in the region surrounding the special field was required to establish fundamental geologic facts.
Date: 1912
Creator: Boutwell, J. M.
Partner: UNT Libraries Government Documents Department

The Significance of Geologic Conditions in Naval Petroleum Reserves No. 3, Wyoming

Description: From Introduction: The work on which this report is based consisted of detailed field and office studies which occupied the greater part of the summer of 1927. During this period mapping was done with plane table and telescopic alidade on a scale of 1 inch to 1,000 feet, and wells, faults, and outcrops within the productive part of the Teapot field were located in detail.
Date: 1931
Creator: Thom, W. T., Jr. & Spieker, Edmund M.
Partner: UNT Libraries Government Documents Department

Stratigraphy of Outcropping Permian Rocks in Parts of Northeastern Arizona and Adjacent Areas

Description: From introduction: In the spring and early summer of 1950 the writers undertook an investigation of the outcropping Permian rocks in northeastern Arizona, northwestern New Mexico, and parts of southern Utah. This work had as its specific objective the establishing of correlations of Permian rocks in the Zuni uplift, Defiance uplift, and Monument Valley upwarp. The determination of these relations, it is believed, will be of aid in the current activities of the Geological Survey in the Navajo Reservation which have as objectives the investigation of the mineral fuels and water resources of the area.
Date: 1961
Creator: Read, C. B. & Wanek, Alexander A.
Partner: UNT Libraries Government Documents Department

The Upper Cretaceous Ammonite Genus Barroisiceras in the United States

Description: From introduction: The ammonite genus Barroisiceras Grossouvre is noteworthy because of its wide geographic distribution and its apparently small stratigraphic range. It is reported from deposits of Coniacian age in Europe, Africa, South America, and North America. In the North American Upper Cretaceous it is rather rare, authentic species having been recognized hitherto only in the Austin chalk of Texas, in the Coniacian beds of Zumpango del Rio, Guerrero, Mexico, and, with doubt as to the source, in New Jersey. The Texan species, B. dentatocarinatum (Roemer), is by no means an abundant form, though among those described in early work in the region. The Mexican representatives of the genus thus far described include only fragmentary specimens not specifically named. The occurrence ascribed to New Jersey is based on a fragment that seems to belong to Barroisiceras but whose source is very doubtful.
Date: 1931
Creator: Reeside, John B., Jr.
Partner: UNT Libraries Government Documents Department

Lithologic Studies of Fine-Grained Upper Cretaceous Sedimentary Rocks of the Black Hills Region

Description: More than nine-tenths of the Upper Cretaceous rocks in northeastern Wyoming are fine-grained shales, mudstones, and calcareous marls. A comparative study of the mineralogy, chemical and mechanical composition, density and porosity, fissility, and lamination of samples of these rocks discloses several relations that throw light on the geologic history and structural deformation of the region, and perhaps on its oil and gas possibilities.
Date: 1930
Creator: Rubey, William Walden
Partner: UNT Libraries Government Documents Department

Glaciation in Alaska

Description: From introduction: The history of glaciation in Alaska offers a fascinating field for study. Because of the remarkable development and easy accessibility of valley and piedmont glaciers in the coastal mountains, Alaska has long been popularly conceived as a land of ice and snow, a concept that is only slowly being corrected. To the student of glaciation, however, Alaska affords a unique opportunity to observe the formation, movement, and dissipation of the many living glaciers, to examine the results of glacial erosion on a gigantic scale, and to discover and work out the sequence of Pleistocene events as shown by the topographic forms in both glaciated and unglaciated areas and by the deposits left by ice and water during earlier stages of glaciation.
Date: 1931
Creator: Capps, Stephen R.
Partner: UNT Libraries Government Documents Department

Gold Quartz Veins of the Alleghany District, California

Description: From Outline of the Report: The Alleghany district, in the southern part of Sierra County, Calif., has long been famous for the high-grade gold ore of its quartz veins. The oldest rocks of the district (pp. 6-17) are of sedimentary and volcanic origin and correspond to part of the Calaveras formation as mapped in the Colfax and Downieville folios of the Geologic Atlas of the United States. These rocks are divided into five formations, of which three-the Blue Canyon, Relief, and Cape Horn formations follow the definitions laid down by Lindgren in the Colfax folio, and two-the Tightner and Kanaka formations-are new units required by the more detailed nature of the present study. It is thought possible that a conglomerate which forms the basal part of the Kanaka formation is of glacial origin. Intrusions of gabbro and more basic rocks, the latter now completely serpentinized, crop out over nearly half the area in which pre-Tertiary rocks are exposed. Small granitic dikes of later age than the basic intrusives are found in the western part of the district. Overlying and largely concealing the older rocks are auriferous gravel of Eocene and Miocene age, andesitic breccia of probable Miocen age, basalt flows of probable Pleistocene age, and minor amounts of Pleistocene and Recent gravel.
Date: 1932
Creator: Ferguson, Henry G. & Gannett, Roger W.
Partner: UNT Libraries Government Documents Department

A Miocene Flora From Grand Coulee, Washington

Description: From introduction: The fossil plants described in the present report were collected at the north end of Grand Coulee during the summer of 1927 by Messrs. T. A. Bonser, F. A. Roberts, and Walter Bruce, of Spokane, and F. W. McCann, of Coulee City. The locality is in the big bend of the Columbia River near the northern boundary of Grant County, Wash., about 85 miles west of the plant-bearing Latah sediments around Spokane. The outcrop in Grand Coulee is about the same distance east of the crest of the Cascade Mountains, about 100 miles northeast of the plant beds at Ellensburg, which are of approximately the same age, and some 200 miles west of beds in Idaho yielding a similar flora and assigned to the Payette formation by Knowlton and others.
Date: 1931
Creator: Berry, Edward Wilber
Partner: UNT Libraries Government Documents Department

Miocene Foraminifera of the Coastal Plain of the Eastern United States

Description: From introduction: In the following report the species of Foraminifera found in the Miocene of the Coastal Plain region of the eastern United States from Florida to Maryland are described and recorded. Numerous papers have been published on this region, some of which, however, are largely lists. Where the original material on which a paper was based has not been available for the present study, the records have been omitted, as it is very difficult to place the species in their proper position without seeing the actual specimens.
Date: 1933
Creator: Cushman, Joseph A. & Cahill, Edgar D.
Partner: UNT Libraries Government Documents Department

Origin of the Anhydrite Cap Rock of American Salt Domes

Description: From abstract: The thesis of this paper is that the anhydrite cap rock of salt domes originated by the residual accumulation and consolidation, on top of a salt stock, of sedimentary anhydrite freed from the salt by solution of the top of the stock. This hypothesis is compared with that of origin from a bed of sedimentary anhydrite supposed to have overlain the salt of the salt stock in depth and to have been forced up on top of the stock as it rose. The strongest basis for the hypothesis of residual accumulation is the presence, between the anhydrite cap rock and the top of the salt stock on many salt domes, of a flat solution surface, the "salt table," decapitating anhydrite-bearing folds in the salt. The paper considers other general geologic evidence and internal petrographic evidence with a view to ascertaining to what extent they confirm or at least fit this interpretation.
Date: 1933
Creator: Goldman, Marcus I.
Partner: UNT Libraries Government Documents Department

Pliocene Fossils From Limestone in Southern Florida

Description: Abstract: This paper describes the mollusks and echinoids found in limestone dredged from ditches along the Tamiami Trail in southern Florida, in the area mapped as "Lostmans River limestone (Quaternary)" by Sanford but included in the Pliocene Caloosahatchee formation by Cooke and Mossom on the evidence of these fossils as identified by Mansfield. The matrix of the fossils is unlike the typical Caloosahatchee formation, which is sandy, but the fauna is closely related to that of the upper part of the Caloosahatchee formation and is regarded as a facies of the Caloosahatchee. The fauna shows considerable resemblance to that of the Imperial formation of California but may not be contemporaneous with it.
Date: 1931
Creator: Mansfield, Wendell C.
Partner: UNT Libraries Government Documents Department