Fluvial and coastal depositional environments may have been quite different before the development of land plants in the late Silurian. Rapid drainage of terrestrial surfaces, flashy rivers with poorly stabilized banks, coarse sediment loads supplied to coasts from landscapes dominated by physical weathering, and the prevalence of epicontinental seas are expected to have altered depositional patterns and associated preserved Facies. Quarries in the Upper Cambrian Hickory Sandstone located in central Texas provide an exceptional opportunity to examine the sedimentology of deposits of this age in order to interpret sedimentary environments. During quarrying, vertical walls, one half-kilometer long and several tens of meters high, are blasted back a few tens of meters at a time and then the rubble excavated, exposing successive outcrops in walls that are perpendicular to the regional paleocurrent direction. The deposits are characterized by sheet-like bedsets dominated by unidirectional cross-stratified sandstones interpreted to have formed in coastal areas fed by bedload dominated rivers. Thinner heterolithic and clay beds locally separating cross-stratified bedsets are commonly bioturbated by marine organisms. Presence of tidal features, such as abundant mud drapes, concave-upward cross-stratification and sparse herringbone cross-stratification, also suggests marine influence during deposition. Detailed mapping of stratal geometry and Facies across these exposures shows a complex internal architecture that can be interpreted in terms of growth and superposition of bars within shallow fluvial channels and adjacent shallow marine areas along the coast. Detailed 3D reconstruction of bars and channels reveals a range of processes including growth, coalescence, and erosion of bars during channel migration, switching and filling of channel segments, and mouth bar growth as channelised flows decelerated seaward. Sedimentary Facies, stratal geometry and ichnofossils suggest that these deposits were formed in a braid-delta system fed by lowsinuosity bedload-dominated rivers. Basinal processes were controlled by the shallow epicontinental sea, dissipating wave action and strengthening tidal currents.

This research characterized a system of small faults (displacement < 0.3 m) in seven closely-spaced continuous 2.4 inch (6.1 cm) diameter cores. Cores were obtained from central Texas, on the western edge of the Llano Uplift. Cores penetrate a dip-slip dominant, normal fault (Nobles Fault) with 18.3 m (60 ft) of stratigraphic throw. The spatial, geometric and kinematic attributes of small faults within the Nobles Fault system were characterized to explore potential cause-and-effect relationships. To quantify spatial distributions, a "density" measure based on individual small fault magnitude was utilized. Approximately half of the small faults in the core possessed no discernible offset markers; thus displacement amount for these faults could not be measured directly. Using a nonparametric method in which an alternating conditional expectation determined optimal transformations for the data, a statistically significant empirical correlation was established for faults with measurable gouge thickness, displacement, protolith mean grain size and sorting. Gouge thickness of small faults was found to be dependant upon the displacement amount of the small fault and the textural characteristics of the host protolith. The role of protolith lithology, proximity to crystalline basement, and structural position relative to the Nobles Fault system were examined to explain observed ubiquitous spatial distribution of small faults. Small faults were found to occur in clusters and the number of faults per foot only weakly correlates to the cumulative displacement of the corresponding faults. The amount of mudstone present is the dominant factor controlling small fault formation. Intervals with only minor quantities of mudstone have the largest number of faults per foot as well as largest associated cumulative displacement per foot. Frequency of occurrence of small faults near the basement is greater when compared to similar lithologies higher in the core. Intensity of small faults do not universally increase with proximity to large faults. To observe an increase in small faults, it is necessary to use a mean global cumulative displacement approach. Zones of greater than average cumulative displacement of small faults in close proximity to large faults were observed in zones that are compatible with faultfault interaction.

Reservoir compartments, typical targets for new infill locations, are commonly created by faults that may reduce or enhanced permeabilities. Faults often contain narrow zones of intense shear comprised of geometrically complex elements that reduce permeability and compartmentalize blocks as a function of time and pressure. This thesis characterizes the permeability structure of shear zones and the relationship between fault permeability, host rock properties and the relative degree of deformation. The main objectives of this work are to (1) characterize the geometry and permeability of deformation elements within shear zones; (2) determine permeability anisotropy in shear zones according to fault characteristics and host lithology; and (3) develop a process to predict permeability anisotropy of faults in reservoirs using probabilistic approaches. The study results give a better understanding of fluid flow behavior of shear zones and their potential to create reservoir heterogeneity and compartmentalization. Fluid flow in a reservoir with faults is controlled by variables such as fault throw, shear-zone thickness, undeformed and deformed rock permeability and the geometry of all deformation elements. Methodology to predict permeability structure was developed using analytical and numerical simulation of selected core samples and laboratory measurements. We found useful relationships between permeability of the host rock and highly deformed elements according to the amount of throw of the fault. The high lateral continuity of the highly deformed elements and their predictable low permeability make these elements most important in controlling permeability in shale-free and low-shale shear zones created by low displacement (subseismic) faulting. Probe permeameter data is a precise, inexpensive and non-destructive source of permeability information that can be effectively incorporated in detailed models to investigate the effect of individual deformation elements in the whole shear zone permeability and their effect at the field scale.

Present models suggest that fluvial and marine depositional patterns were distinct from modern patterns prior to the appearance of land plants. Although these models are likely correct, problems exist when one attempts to distinguish between fluvial and shallow marine deposits in pre-Silurian strata, making it difficult to accurately determine depositional patterns. The lack of land plants and scarcity of body and trace fossils, especially in Precambrian and early Cambrian strata, make identification difficult. Based on core data and limited outcrops, the Lower Hickory Sandstone, a late Cambrian sandstone, has been interpreted to progress from fluvial to shallow marine. These data have allowed the development of an overall depositional model, but minimal detail of facies changes is available. Based on the limited data, both deltaic and estuarine models have been suggested for the Lower Hickory. Mining of the Lower Hickory for frac sand has created highwalls in the CarmeuseNA Mine, which provides an opportunity to study facies changes at this site. The CarmeuseNA Mine, located in McCulloch County, Texas, has exposed the formation along ~500 m long and 20 m-high faces, respectively. Because of limited exposure, only the south and west walls, as well as part of the east wall, could be examined. Digital photographs of the faces were mosaiced using standard photogrammetrical practices to produce visual representation of the highwalls. Bedding geometry was then mapped on the digital images to facilitate a detailed interpretation of the depositional process. Core and well data were used to map Hickory thickness to produce an isopach map. Four primary facies were observed in the quarry, dominated by small-scale and large-scale cross-bedding. Paleocurrents are generally unidirectional to the southsoutheast indicating a braided fluvial origin, but rarely opposing directions are seen. Bioturbation is rare low in the section, but increases upwards. Together with the rare herringbone cross-bedding, clay drapes, and bioturbation, a tidal influence is strongly suggested. The model suggested is a braided stream setting influenced and reworked by tides. A braided-delta fed by braided streams guided by a ridge and swale-dominated setting, which served as the sediment supply for the delta, is proposed.

This thesis explores the Hicoria genus and focuses on the Stuart variety of pecan tree. Experimentation yielded the ash constituents, fats, fat constants, crude fiber, protein, and sugar in shelled pecan samples.

No description available.

No description available.

The hickory shad (Alosa mediocris) is a relatively understudied species of the anadromous fish sub-family Alosinae. This study, the first population genetic analysis of this species, employed 12 neutral microsatellite loci to estimate genetic diversity and population structure in tributaries of lower Chesapeake Bay, Virginia including James River and its tributaries (Appomattox and Chickahominy Rivers), Rappahannock River, and Pamunkey River. Genetic variation was extremely low. Estimates of observed heterozygosity were lower than expected heterozygosity. Significant population structure was detected among the six samples (FST = 0.093, p = 0.01). Effective population sizes were low (Ne ranged from 2 to 134). The lack of genetic diversity, especially compared to that of the American shad, was striking and could be the result of a bottleneck that took place more than thirty years ago which may plausibly account for the low genetic variation observed across all populations.

A magnetic study over a 95 m x 150 m area of the Hickory sandstone aquifer in central Texas was carried out as part of multitechnique geophysical investigation that included ground penetrating radar (GPR), electromagnetic (EM), seismic and seimoelectric. In geophysical exploration, the magnetic method can be utilized as an alternative to more expensive methods, such as seismic or it can be used to complement other methods. In this thesis, the magnetic method is applied to estimate the location of a previously mapped fault by Texas A&M geology students, and it is used to estimate the magnetic susceptibility contrast of the targeted fault. The main challenge of this study is imaging shallow faults using the geophysical magnetic method in a fractured aquifer with widely-scattered distribution of iron bearing rocks as in the case of the Hickory sandstone aquifer. A Geometric—G858 Cesium vapor magnetometer was used to collect magnetic data. The data consisted of 19 north-south and 1 east-west lines acquired in October and November of 2012. Elementary data processing such as diurnal correction, regional correction, reduction to pole (RTP) filter, Euler deconvolution, forward modeling and inversion were employed to characterize the faulted zone. This faulted zone separates granite basement rocks from the Hickory sandstone. As a result, this study emphasizes that Euler deconvolution applied to RTP-filtered data increases the interpretability of geological and structural contacts. The results of the magnetic method have been compared to results of GPR, EM and seismoelectric methods. Understanding the magnetic mineralogy of rocks and their properties can improve the geological interpretation of magnetic surveys.

In the greater Central Hardwood Region, advance regeneration of oak (Quercus spp.) and hickory (Carya spp.) has been in decline for several decades. Facilitated in part by an abrupt change in disturbance regime, coupled with an increase in herbivore density, the existing mid-successional, mast-producing species are being outcompeted by late-successional, mesophytic species. Oak-hickory forests provide keystone resources for a diverse forest wildlife community, and a decline in its dominance will likely impact habitat use and occupancy patterns in the mammal community, but to what extent is unclear. During May-August 2015-2016, I deployed 150 remotely-triggered camera traps in Trail of Tears State Forest (TTSF), Union County, Illinois to investigate single-season, site occupancy patterns and detection probabilities as a function of forest composition and structure for 3 mammals (eastern gray squirrel [Sciurus carolinensis], raccoon [Procyon lotor], and white-tailed deer [Odocoileus virginianus]). I collected microhabitat data at each camera-site and utilized a GIS application to estimate spatial relationships among anthropogenic features and camera-sites. I recorded 404 photographs of 11 endothermic species during 3927 days of survey effort, with white-tailed deer, raccoons, and eastern gray squirrels as the most detected species, respectively. Detection probability of eastern gray squirrels was best explained by the global detection model, indicating no covariate measured explained the variation in detection rates. Raccoon detection probability was best described by a negative relationship with the average temperature recorded during survey period. The best-fitting detection model for white-tailed deer indicated detection probabilities declined throughout the sampling period and across seasons. Eastern gray squirrel site occupancy models received little support, however, ecological land type phase was the most supported model. The best fitting habitat model described a negative relationship between eastern gray squirrel site occupancy probability and coarse woody debris volume. For raccoons, no model with habitat covariates was better fitting than the null model. Raccoon occupancy probability increased with maximum DBH at a site, ground cover, and beech-maple importance values, but decreased with oak-hickory importance values. White-tailed deer occupancy was most positively influenced by ground cover and oak-hickory importance values, but decreased with distance to forest edge, number of understory stems, and beech-maple importance values. My research provides empirical evidence to predictions made regarding the impact of a decline in oak dominance across the Central Hardwood region on a portion of the region’s mammal community. Shifts to late-successional conditions in the Central Hardwood region will likely continue and magnify if forest management approaches continue to minimize the frequency and occurrence of large, anthropogenic disturbances to the forest overstory. A mosaic of forest conditions will be needed to best support a diverse and complete mammal community across the region.