Report of Investigations No. 131 Origin and Diagenesis of Cap Rock, Gyp Hill and Oakwood Salt Domes, Texas

UT Librarie

Radiation induced zero-resistance states: a dressed electronic structure effect

Recent results on magnetoresistance in a two dimensional electron gas under crossed magnetic and microwave fields show a new class of oscillations, suggesting a new kind of zero-resistance states. A complete understanding of the effect is still lacking. We consider the problem from the point of view of the electronic structure dressed by photons due to a in plane linearly polarized ac field. The dramatic changes in the dressed electronic structure lead to a interpretation of the new magnetoresistance oscillations as a persistent-current like effect, induced by the radiation field.Comment: 5 pages, 5 figures, revtex4, changes in introduction and added reference

Report of Investigations No. 123 Petroleum Potential of the Palo Duro Basin, Texas Panhandle

UT Librarie

The Evolution of Post-Starburst Galaxies from z∼1z\sim1 to the Present

Post-starburst galaxies are in the transitional stage between blue, star-forming galaxies and red, quiescent galaxies, and therefore hold important clues for our understanding of galaxy evolution. In this paper, we systematically searched for and identified a large sample of post-starburst galaxies from the spectroscopic dataset of the Sloan Digital Sky Survey (SDSS) Data Release 9. In total, we found more than 6000 objects with redshifts between $z\sim0.05$ and $z\sim1.3$, making this the largest sample of post-starburst galaxies in the literature. We calculated the luminosity function of the post-starburst galaxies using two uniformly selected subsamples: the SDSS Main Galaxy Sample and the Baryon Oscillation Spectroscopic Survey CMASS Sample. The luminosity functions are reasonably fit by half-Gaussian functions. The peak magnitudes shift as a function of redshift from $M\sim-23.5$ at $z\sim0.8$ to $M\sim-20.3$ at $z\sim0.1$. This is consistent with the downsizing trend, whereby more massive galaxies form earlier than low-mass galaxies. We compared the mass of the post-starburst stellar population found in our sample to the decline of the global star-formation rate and found that only a small amount ($\sim1\%$) of all star-formation quenching in the redshift range $z=0.2-0.7$ results in post-starburst galaxies in the luminosity range our sample is sensitive to. Therefore, luminous post-starburst galaxies are not the place where most of the decline in star-formation rate of the universe is happening.Comment: 26 pages, 24 figures, 8 tables. Accepted for publication in The Astrophysical Journa

Social Work Practice with West Indian Immigrant Families

The University Archives has determined that this item is of continuing value to OSU's history.Presenter: Shirley P. Thrasher, D.S.W., A.C.S.W., Assistant Professor, Wayne State University, School of Social Work, Detroit, Michigan - "Social Work Practice with West Indian Immigrant Families".The Ohio State University College of Social Wor

State Lands Energy Resource Optimization Project

Project SLERO, for which The University of Texas at Austin Bureau of Economic Geology was the lead contractor and coordinating institution, was a five-university consortium study of hydrocarbon resources on Texas State Lands. The five universities are The University of Texas at Austin, Texas A&M University, the University of Houston, Texas Tech University, and Lamar University, and the entire program was aided by the cooperation of the Texas General Land Office. This 4-year project was funded through the Office of the Governor of Texas. Project personnel included geologists, petroleum engineers, geophysicists, and chemists. The interdisciplinary nature of this project was directed toward a more thorough understanding of the geologic controls on production and the development of appropriate recovery technologies to address the specific needs of State Lands reservoirs. Transfer of these technologies to industry, in particular to independent operators, is expected to result in increased efficiency of hydrocarbon recovery from State Lands and increased revenue to the Texas Public School Fund. The project was divided into three parts: (1) play analysis and resource assessment, (2) reservoir characterization, and (3) development of advanced extraction technology.Bureau of Economic Geolog

Petrography and Diagenesis of the Travis Peak (Hosston) Formation, East Texas

Petrographic studies of the Travis Peak Formation in East Texas were used to interpret the diagenetic history of Travis Peak sandstones and to relate the diagenetic history to permeability variations within the formation. Travis Peak sandstones are fine to very fine-grained quartzarenites and subarkoses that were derived from sedimentary, metamorphic, and igneous rocks exposed in a large area of the southwestern United States. The originally high depositional porosity in matrix-free sandstones was reduced by compaction and precipitation of authigenic cements, particularly quartz, ankerite, illite, and chlorite. In addition, reservoir bitumen, a high molecular weight hydrocarbon residue, occludes porosity in some zones near the top of the Travis Peak. Porosity and permeability have a wide range of values at the top of the formation, but both the range of values and the maximum values decrease with depth below the top of the Travis Peak. Dissolution of orthoclase and plagioclase has formed most of the secondary porosity. Porosimeter-measured porosity is the best predictor of permeability, and there is a significant inverse correlation between the total volume of cement and permeability.Bureau of Economic Geolog

Diagenesis and Burial History of the Lower Cretaceous Travis Peak Formation, East Texas: Controls on Permeability in a Tight Gas Sandstone

Petrographic and geochemical studies were used to determine the diagenetic and burial history of Travis Peak sandstones in East Texas and to relate the diagenesis to permeability variations within the formation. Permeability in much of the formation has been reduced to less than 0.1 md by compaction, cementation, and minor pressure solution. Travis Peak sandstone is quartzarenite and subarkose, having an average composition of Q95F4R1. The first authigenic cements to precipitate were illite, which coated detrital grains with tangentially oriented crystals, and dolomite. Next, extensive quartz cement, averaging 17% of the rock volume in well-sorted sandstone, occluded much of the primary porosity. Quartz is most abundant in the lower Travis Peak, in well-connected sandstone beds that were deposited in braided streams. Dissolution of orthoclase and albitization of plagioclase followed quartz cementation and occurred prior to mid-Cretaceous movement of the Sabine Uplift. Illite, chlorite, and ankerite precipitated after feldspar diagenesis. Oil migrated into Travis Peak reservoirs in the Late Cretaceous from Jurassic source rocks. Later deasphalting of the oil filled much of the remaining porosity in some zones near the top of the formation with reservoir bitumen.Bureau of Economic Geolog