No description available.

The late Permian Queen Formation (115 m thick) is a succession of mixed clastics, carbonates and evaporites deposited in the northeastern margin of Central Basin Platform of the Permian Basin, west Texas, USA. Depositional facies, stacking patterns of cyclic facies associations and statistical correlation of rock property variations define geologic controls on reservoir rock properties. Textural, compositional, petrophysical and diagenetic variations within lithofacies exhibit systematic changes with stratigraphic position, which can be related to base level changes that were controlled by high-frequency, low-amplitude, sea level fluctuations during a greenhouse period. Ten lithofacies record variations in clastic input, shallow marine carbonate production, and evaporate precipitation in sabhkas and salinas. Four different types of lithofacies associations define: (1) transgressive deltaic deposits; (2) upward-shallowing evaporite and carbonate tidal-flat deposits; (3) transgressive beach ridge and sand flat deposits; and (4) upward-shallowing evaporite salina-sabhka deposits. Stacking patterns of lithofacies associations define sixteen depositional cycles that can be grouped into eight cycle sets. Cycle sets in turn are grouped to define two high-frequency sequences. Sequence 1 progresses from fluvial to carbonate tidal flat cycles. Sequence 2 consists of salina-dominated upward-shoaling cycles. Lateral continuity of cycles indicates restricted sedimentation on low-accommodation inner platform areas updip of prograding highstand platform-margin carbonate buildups, and a long-term trend of accommodation decrease. The Queen Formation contains two reservoir types; (1) siliciclastic reservoirs capped by evaporites and (2) layer-cake carbonate reservoirs. Of the four reservoir zones identified, R11 in lowstand fluvial-deltaic deposits has relatively little cement and the best reservoir characters.

Engine Running: Essays is a collection of creative nonfiction that explores, in parts, a persona's distancing from home and self against the backdrop of an increasingly fractured family doing the same. Through a variety of forms, the essays seek to balance themes like loss, self-discovery, and manhood in reflections on the role of childhood memory, the early revelations and experimentation of sexuality, and the carving-out of personal identity in West Texas.

The Eagle Ford Shale and equivalent Boquillas Formation (Late Cretaceous) contain abundant volcanic ash beds of varying thickness. These ash beds represent a unique facies that displays a range of sedimentary structures, bed continuity, and diagenetic alteration. They are prominent not only in West Texas outcrops, but also in the subsurface of South Texas where hydrocarbon production is actively occurring. The ash beds have the potential to be used for stratigraphic correlation for understanding early diagenesis and — most importantly — for obtaining high-resolution geochronology, which can then be used for defining depositional rates and chronostratigraphy. Study of the ash beds was conducted at outcrops along U.S. 90, west of Comstock, Texas, the subsurface in Atascosa and Karnes County, and at a construction site in South Austin. Bed thicknesses range from 0.1–33 cm and were collected throughout the entirety of the Eagle Ford succession. Mineral separation yielded abundant non-detrital zircons for U-Pb dating. Dating was conducted using LA-ICP-MS at The University of Texas at Austin, to attain a base level understanding of the age range for the Eagle Ford. High-resolution ages for the base and top of the Eagle Ford were obtained, in addition to radioisotopically defining the Cenomanian-Turonian boundary within the section. U-Pb ages for the Eagle Ford Shale range from Early Cenomanian to Late-Coniacian near Comstock, Mid-Cenomanian to the Turonian-Coniacian boundary in the subsurface, and Early Cenomanian to Late Turonian in Austin area. These findings contrast with many of the regional biostratigraphic studies across the Eagle Ford and indicate a more prolonged period of Eagle Ford deposition than previously observed. / text

The Black Shale Basin of West Texas covers an area in excess of 21,000 square miles and includes the region from Terrell and Pecos Counties eastward to Menard and Kimble Counties. It extends from Real, Edwards, and Val Verde northward beyond Glasscock and Upton Counties. This basin includes such local basins as the "Midland Basin," and "Val Verde Basin," of Frank E. Lewis, the "Sheffield Channel," and the "Kerr Basin." Reasons are given for the belief that the black shale sediments in this basin were derived from rocks south of this area. The shale ranges in age from Bend (lower Pennsylvanian) through Clear Fork (middle Permian). The shale of the Midland Basin has been divided into three distinct zones. Pre-Cretaceous erosion has removed the offlapping Permian shale in the extreme southern portion of the area leaving Pennsylvanian directly beneath the Trinity. The problem of stratigraphy is complicated by gradation and lack of diagnostic fossils. There is a great divergence of opinion as to correlative formational units derived from a study of the well cuttings. / text

Conceptualizations of actual biological patterns as preserved in the fossil record must accommodate the results of biotic and abiotic drivers of faunal dynamics. However, those conceptualizations also may reflect cognitive biases resulting from foundational philosophical stances. Whether fossils are conceptualized as the remains of biological entities or as geological objects will affect both taxonomic identifications and secondary inferences derived from those identifications. In addition, operational research bias centered on relativistic views of ‘importance’ of particular components (i.e., taxonomic or skeletal region) of the assemblage results in preferential documentation of some taxa and marginalization of others. I explored the consequences of those specific cognitive and operational biases through examination of Triassic and Eocene faunal assemblages in western North America. For the Triassic I focused on taxonomic and systematic treatments of Paleorhinus, a group of phytosaurs important for the establishment of biochronologic correlations. Specimen-level reexamination of Paleorhinus supported a restricted usage of Paleorhinus as a clade, dissolved a biochronologic connection between terrestrial and marine deposits, and indicated a prior compression of the early part of the Late Triassic as a result of previous conceptualizations of species. I reexamined the Otis Chalk tetrapod assemblage in light of new specimens and modern phylogenetic frameworks. My examination supported a restricted usage of the Otischalkian for biochronologic correlation of the Late Triassic, and emphasized the importance of apomorphic character-based specimen examinations in conjunction with detailed lithostratigraphy prior to the development of biochronologic schema. For the Eocene I focused on undocumented terrestrial reptiles from the late Uintan fauna of West Texas. Specifically I discovered new taxa and new geographic occurrences of amphisbaenians and caimanine crocodylians. The amphisbaenians represent the southernmost record of the clade in the North American Paleogene, and, when combined with other amphisbaenian records, document that the clade responded to late Paleogene climatic changes in ways different from the inferred mammalian response. The new taxon of caimanine crocodylian represents a new geographic and temporal record of that clade. That new record indicates that the biogeographic range of extant caimans represents a climate-driven restriction from a formerly more expansive range, and suggests that the previous geographic and temporal gap in paleodistribution data is related to sampling biases and is not a solely a biological phenomenon. These data indicate that reliable characterization of vertebrate faunal dynamics requires open acknowledgment and appropriate documentation of cognitive and operational biases that affect interpretations of paleontological data. / text

The Woodford Shale is an important unconventional oil and gas resource. It can act as a source rock, seal and reservoir, and may have significant elastic anisotropy, which would greatly affect seismic response. Understanding how anisotropy may affect the seismic response of the Woodford Shale is important in processing and interpreting surface reflection seismic data. The objective of this study is to identify the differences between isotropic and anisotropic seismic responses in the Woodford Shale, and to understand how these anisotropy parameters and physical properties influence the resultant synthetic seismograms. I divide the Woodford Shale into three different units based on the data from the Pioneer Reliance Triple Crown #1 (RTC #1) borehole, which includes density, gamma ray, resistivity, sonic, dipole sonic logs, part of imaging (FMI) logs, elemental capture spectroscopy (ECS) and X-ray diffraction (XRD) data from core samples. Different elastic parameters based on the well log data are used as input models to generate synthetic seismograms. I use a vertical impulsive source, which generates P-P, P-SV and SV-SV waves, and three component receivers for synthetic modeling. Sensitivity study is performed by assuming different anisotropic scenarios in the Woodford Shale, including vertical transverse isotropy (VTI), horizontal transverse isotropy (HTI) and orthorhombic anisotropy. Through the simulation, I demonstrate that there are notable differences in the seismic response between isotropic and anisotropic models. Three different types of elastic waves, i.e., P-P, P-SV and SV-SV waves respond differently to anisotropy parameter changes. Results suggest that multicomponent data might be useful in analyzing the anisotropy for the surface seismic data. Results also indicate the sensitivity offset range might be helpful in determining the location for prestack seismic amplitude analysis. All these findings demonstrate the potentially useful sensitivity parameters to the seismic data. The paucity of data resources limits the evaluation of the anisotropy in the Woodford. However, the seismic modeling with different type of anisotropy assumptions leads to understand what type of anisotropy and how this anisotropy affects the change of seismic data. / text

The eastern side of the Guadalupe Mountains, located in New Mexico and west Texas, represents an erosional profile along the Capitan reef margin. A complete shelf-to-basin exposure of the Upper Permian Capitan shelf margin is found on the north wall of North McKittrick Canyon, which is nearly perpendicular to the Capitan reef margin. An excellent 2-D sequence stratigraphic framework for upper Permian backreef facies has been developed by previous workers for North McKittrick Canyon (Tinker, 1998) and Slaughter Canyon (Osleger, 1998), forming the basis for observations in this study. The goal of this study is to describe the sequence stratigraphic architecture of the Yates Formation, focusing on the Y4-Y6 high-frequency sequences (HFSs) found in the middle to outer shelf depositional systems, and to illustrate the use of airborne lidar data to quantitatively map at the cycle-scale. Seven measured sections were taken in North McKittrick Canyon. From airborne lidar, 3-D geometries of key sedimentary and structural features were mapped in Polyworks, in addition to the sequence boundaries delineating the Yates 4-6 HFSs. In general, major cycles exhibit asymmetry and shoal upward. Cycle boundaries are sometimes hard to delineate due to amalgamation, particularly in the shelf crest. High-frequency sequences are commonly asymmetric; they deepen and thicken upward toward the maximum flooding surface, and the boundaries between HFSs are usually marked by thick siltstones. Major HFS boundaries can be mapped across the entire dataset, and some component cycles can be observed for minimum distances of one kilometer in an updip-downdip direction. Also, some facies tract dimensions can be estimated directly from the lidar data. Measured sections indicate that the shelf crest facies tract shifts seaward with each successive HFS, while the outer shelf facies tract steps landward. Future work that could be done with the Y4-Y6 HFSs includes 8-10 more measured sections, collection of samples for thin sections, and tracing out of contacts between facies tracts. Extensive lidar data interpretation needs to be done so that digital outcrop models demonstrating facies distributions can be produced. This would enable the development of an outcrop analog model to mixed carbonate-siliciclastic reservoirs, which would be unprecedented in this area. / text

A life history study of Callibaetis floridanus was conducted over the wet cycle of a playa on the Southern High Plains of Texas from June through September 1995.

In the novel Elvis Plays Texas, which is my Thesis project to meet the requirements for a Master of Fine Arts in Creative Writing/Fiction, a little town in far, far West Texas and its people are having a very difficult time and facing what promises to be a bleak future—a long, long drought has exhausted their water supply, oil has peaked and turned down, “fracking” threatens their way of life, friends and family and neighbors are loading up and leaving town. Then, Elvis Presley shows up. It’s the 40th anniversary of the day he died, August 16, 1977, and he, spiritually though appearing in every way to be flesh and blood, is visiting those who’ve continued believing in him and to whom he had been particularly important during their younger lives. My own long history in that part of the country has played its considerable role in informing the setting, the tone, the atmosphere. These are the kinds of characters—strange birds all—I grew up with. The country is the southwestern desert, hot, dry, empty, big sky—the kind of neighborhood that lends itself to oddities like Elvis throwing a benefit concert to help them out of the economic ditch.