Browsing by Subject "Geology"
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Item A carbon isotope and trace element analysis of Pennsylvanian rugose corals, North-Central Texas(Texas Tech University, 1989-12) Perkins, DianeCarbon and oxygen isotopes were analyzed to identify the process of algal symbiosis in Pennslyvanian rugose corals from the Graham Formation of north-central Texas. Because original oxygen and carbon isotopic compositions depend on the preservation of isotopic content during post-depositional diagenesis, trace element and petrographic analyses were used to determine the suitability of samples of Caninia, Lophophyllidum and the brachiopod Composita for analysis. Petrographic analysis of fossils from the Finis Shale indicate that these fossils have been subjected to four episodes of diagenetic cementation. Shell microstructures are partially preserved in Composita and Caninia. Recrystallization of the shell was more extensive in Lophophyllidum from the Finis Shale and Caninia from the Gunsight Limestone. Six episodes of cementation are recognized in Caninia from the Gunsight Limestone. Trace element analysis indicates that sodium and magnesium values are depleted and iron and manganese concentrations enriched in Caninia from the Finis Shale. Trace element analysis of Composita indicate that sodium, iron, manganese and strontium concentrations are within the observed range for Paleozoic brachiopods. Isotopic analyses of Caninia and Lophophyllidum exhibit 6 ^^C and 6 ^^0 values depleted compared to Composita and to the postulated range for carbonate precipitated in equilibrium with Pennsylvanian seawater. These findings suggest that an algal symbiont influenced the development of the coral skeleton.Item A Gravity and Magnetic Investigation of the Amarillo Uplift(Texas Tech University, 1969-05) Danbom, Stephen HNot Available.Item A gravity and magnetic investigation of the Matador Uplift(Texas Tech University, 1968-06) Bitgood, Charles D.Not availableItem A microfacies analysis of a Virgilian algal biherm, Hueco Mountains, Texas(Texas Tech University, 1969-05) Reed, James CourtneyNOT AVAILABLEItem Item A petrofabric analysis of the Cox Sandstone, Hudspeth County, Texas(Texas Tech University, 1960-05) Mount, J. RussellNot availableItem A petrographic study of the subsurface Gallup Sandstone of San Juan County, New Mexico(Texas Tech University, 1956-08) Williams, Jack R.Recent exploration by petroleum companies has resulted in renewed interest in the subsurface Gallup Sandstone of the San Juan Basin, New Mexico. The present study provides detailed petrographic descriptions of samples from six wells and interpretation of the data obtained. Locations of the six wells are such that they follow the line of strike of the formation, and lithologies are similar at all locations. Quartz is the predominant mineral in all cases, with cacite being the most important cementing agent. The sporadic occurrence of siliceous cement is fre31quent enough to present a factor for consideration in any program of rock treatment for the purpose of increasing permeability. The most favorable area for additional exploration is believed to be to the south and southwest of the line of wells studied.Item A provenance study of the lower Cretaceous Yucca beds(Texas Tech University, 1963-08) Pac, FloydNot availableItem A Provenance Study of the Triassic Deposits of Northwestern Texas(Texas Tech University, 1960-05) Kiatta, Howard WilliamContinental deposits of the Upper Triassic Dockum Group are exposed along the eastern escarpment of the Southern High Plains in northwestern Texas. Three formations are present: the Tecovas, the Trujillo, and the Chinle, generally representing the floodplain, stream channel, and floodplain environments respectively. Analyses of the sedimentary structures were made to determine the direction of the source of these beds. Mineralogical studies were conducted in an effort to establish the litho logic character of the source rocks. Results indicate that the provenance consisted chiefly of a terrene of sedimentary rooks to the east and southeast. Specific source areas are proposed and some pale geographic reconstructions are suggested.Item A Sedimentary Analysis of the Queen and Grayburg Formations of Southeastern New Mexico(Texas Tech University, 1958-05) Graves, Frank DouglasNot Available.Item A sedimentary study of the Jurassic of Quay County, New Mexico(Texas Tech University, 1951-05) Smith, Shelby WNot availableItem A sedimentary study of the Ogallala Group, Crosby County, Texas(Texas Tech University, 1951-05) Clifton, Billy BlakeNot availableItem A sedimentary study of the Purgatoire Formation of Quay County, New Mexico(Texas Tech University, 1951-05) Smith, William HenryNot availableItem A study of lacustrine dolomite and associated sediments of Lake Mound, Lynn and Terry counties, Texas(Texas Tech University, 1969-05) Leach, Jerald WayneThe purpose of this study was to collect geological and geochemical data which would aid in describing conditions surrounding the formation of penecontemporaneous dolomite in Lake Moxind. The advantage gained in studying this particular dolomite is that it has not been subjected to processes of extensive diagenesis and offers a model for examining some of the environmental conditions similar to those that existed during the time of dolomite formation. Studies of penecontemporaneous dolomite provide the best information available regarding conditions surrounding the formation of dolomite. When sufficient data become available, it should be possible to isolate conditions essential to the process, to reproduce these in the laboratory, and to synthesize dolomite under conditions which could exist in a natural sedimentary environment.Item A study of Pennsylvanian-Permian arkoses in north-central New Mexico(Texas Tech University, 1950-05) Butler, RoyNot availableItem A Study of the Silurian System and a Silurian Reef in West Texas and Southern New Mexico(Texas Tech University, 1971-05) Cronin, Thomas C.Not Available.Item A study of two isolated Cambrian stromatolitic outcrops, Mason and McCulloch counties, Texas(Texas Tech University, 1987-05) Portnoy, Michael BenjaminNot availableItem A subsurface study of the Pennsylvanian detrital unit, Andrews County, Texas(Texas Tech University, 1985-08) Krenik, Kevin JNot availableItem Analyzing deep-water near seafloor geology with chirp sonar sub-bottom profiles : Green Canyon, Gulf of Mexico(2006-12) Hernandez, Jaime, 1968-; Fisher, W. L. (William Lawrence), 1932-The study area is located on the continental slope in the Green Canyon deep-water area of the Gulf of Mexico. This area is being investigated by the Bureau of Economic Geology as part of several active gas hydrate studies across the area. The chirp sonar profiles used in my study were collected with an Autonomous Underwater Vehicle (AUV) utilizing a frequency-modulated seismic (sonar) source that emitted a 2 to 8 kHz sweep (chirp) frequency signal (wavelengths less than 2 meters). The recording time is limited to about 50 milliseconds, with time zero occurring at the altitude of the AUV about 50 meters above the seafloor. The signal images to about 40 meters below the seafloor, and profiles are as long as 5 km. An interpretation of deep-water, near sea-floor geology has been conducted using both chirp sonar profiles and multibeam bathymetry. Seismic reflections from within the shallow sediments are caused primarily by contrasts in density, rather than acoustic velocity. Reflections were successfully simulated using a model with a constant velocity of 1560 m/s and densities of 2.1 g/cc for sand, 1.4 g/cc for mud, and 1.7 g/cc for silty sand. The chirp sonar profiles imaged near-seafloor geology at nearly a meter scale and allowed for detailed interpretation. The interaction of soft sediment deformation, creep movement and neo-tectonic activity related to gas expulsion controlled the actual topography of the sea-floor. The geologic time represented in the 50 milliseconds of chirp data recorded with the AUV, which is about 40 meters of depth, is approximately 0.050 Ma. B.P., consistent with a depositional rate of 0.8 meters per 1000 years. Reflection patterns are interpreted to be related to fluctuations in sea level. High reflectivities (density contrasts) are interpreted to be deposited during the last sea level low stand, and low reflectivities are interpreted as sedimentation during the last high stand. Sediments deposited during the low stand are proximal while others are distal, deposited in deeper water environments. Shallow structures observed in the chirp sonar profiles are mainly related to gas mobilization mechanisms, which shaped the topography of the seafloor in conjunction with soft sediment deformation and creep movement. The geomorphic features are related in some cases to gas expulsion zones such as pockmarks and mud volcanoes. Other structures are related to soft sediment deformation and creep mobilization. Soft sediment deformation is confined to the deepest part of the minibasin, while the other features are not depth dependent. Highly deformed intervals at the bottom of the sequence seem to control subsequent sedimentation.Item Benedum Field of Upton and Reagan Counties, Texas(Texas Tech University, 1951-01) Nixon, Achilles HarryNot Available.