Expansive clays are located world wide and cause billions of dollars in damage each year. Currently, the expansion is usually estimated using correlations instead of direct testing as direct testing is expensive and often takes over a month to complete. The purpose of this study was to determine if centrifuge technology could be used to characterize expansive clays through direct testing. Testing was performed in an centrifuge permeameter on compacted specimens of Eagle Ford clay. A framework was developed to analyze effective stresses in centrifuge samples and methods were proposed to determine the swell-stress curve of a soil from centrifuge tests. Standard free swell test were also performed for comparison. The swell-stress curve determined by centrifuge testing was found to match with the curve found from free swell tests after correcting for differences in testing procedures. The centrifuge tests were found to be repeatable and required several days for testing rather than weeks. / text

Grain assemblages in organic-rich mudrocks of the Eagle Ford Formation of South Texas are assessed to determine the relative contributions of intra- and extrabasinal sediment sources, with the ultimate goal of producing data of relevance to prediction of diagenetic pathways. Integrated light microscopy, BSE imaging, and X-ray mapping reveal a mixed grain assemblage of calcareous allochems, biosiliceous grains (radiolaria), quartz, feldspar, lithics, and clay minerals. Dominant fossils are pelagic and benthic foraminifers and thin-walled and prismatic mollusks; echinoderms, calcispheres, and oysters are present. Early-formed authigenic minerals, including calcite, kaolinite, dolomite, albite, pyrite, quartz, and Ca-phosphate, some reworked, add to the overall lithologic heterogeneity. Point counting of images produced using energy-dispersive X-ray mapping in the SEM provides observations at a scale appropriate to classifying the mudrocks based on the composition of the grain assemblage, although grains and other crystals of clay-size cannot be fully characterized even with the SEM. Each sample is plotted on a triangle, whose vertices correspond to terrigenous and volcanic grains (extrabasinal components), calcareous allochems, and biosiliceous grains. As a subequal mix of grains of intrabasinal and extrabasinal origins the detrital grain assemblage of the Eagle Ford, presents a formidable challenge to the task of lithologic classification of this unit, as neither conventional limestone nor sandstone classifications can be readily applied. The abundant marine skeletal debris in the Eagle Ford is accompanied by abundant calcite cementation and the dissolution and replacement of biosiliceous debris is accompanied by authigenic quartz, suggesting that mudrock grain classification has potential for yielding diagenetic predictions. / text

Scanning electron microscopy of Ar-ion milled samples from the Eagle Ford Formation, South Texas shows that the character and abundance of porosity changes significantly across burial conditions as a result of compaction, cementation, bitumen generation, and generation of secondary porosity within organic matter (OM). Samples displaying a range of compositions and maturities are imaged and quantified to provide insight into the effects of these processes. Porosity in low-maturity samples (Ro~0.5%) is volumetrically dominated (0.1% -12.5% bulk volume, average 6.2%) by relatively large, mostly interparticle, primary mineral-associated pores (median sizes range 35.9-52.7 nm). Larger pores are generally associated with coccolith debris that is commonly aggregated into pellets. Porosity and pore size correlate directly with calcite abundance and inversely with OM volumes. OM is dominantly detrital kerogen "stringers" that range in size and have spatial distributions and character suggestive of detrital origin. Destruction of primary porosity in low-maturity samples has occurred due to compaction of ductile kerogen and clays and, to a minor degree, as a result of cementation and infill of early bitumen. Smaller, secondary OM-hosted pores (median size range 11.1-14.9 nm) volumetrically dominate porosity (0.02%-3.6% bulk volume, average of 1.36%), in most high-maturity samples (Ro~1.2%-1.3%). Mineral-associated pores are present, but are typically smaller (median size range from 20.3-40.6 nm) and less abundant (0.0%-10.0% bulk volume, average of 2.5%) than at low maturity. Abundant mineral-associated porosity is present locally in samples where incursion of primary pore space by bitumen has not occurred. OM within high-maturity samples is distributed more evenly throughout the rock fabric, occupying spaces similar in size and morphology to primary interparticle pores, coating euhedral crystals (probable cements), and filling intraparticle porosity. These observations, and positive correlation between calcite and OM volumes (OM-hosted pore volume included) in samples with dominantly OM-hosted pore networks, suggests that a large portion of OM within high-maturity samples is diagenetic in origin and has filled primary pore space. Destruction of primary porosity in high-maturity samples has occurred through cementation, bitumen infill, and, possibly greater compaction. Additional porosity, however, has been generated through maturation of OM. / text

Heightened industry focus on the Upper Cretaceous (Cenomanian-Turonian) Eagle Ford has resulted from recent discoveries of producible unconventional petroleum resource in this emerging play. However, little has been published on the facies and facies variabilities within this mixed carbonate-clastic mudrock system. This rock-based study is fundamental to understanding the controls, types, and scales of inherent facies variabilities, which have implications for enhanced comprehension of the Eagle Ford and other mixed carbonate-clastic mudrock systems worldwide. This study utilizes 8 cores and 2 outcrops with a total interval equaling 480 feet and is enhanced by synthesis of thin section, XRD, XRF, isotope, rock eval/TOC, and wireline log data. Central Texas Eagle Ford facies include 1) massive argillaceous mudrock, 2) massive argillaceous foraminiferal mudrock, 3) laminated argillaceous foraminiferal mudrock, 4) laminated foraminiferal wackestone, 5) cross-laminated foraminiferal packstone/grainstone, 6) massive bentonitic claystone, and 7) nodular foraminiferal packstone/grainstone. High degrees of facies variability are observed even at small scales (50 ft) within the Eagle Ford system and are characterized by pinching and swelling of units, lateral facies changes, truncations, and locally restricted units. Facies variability is attributed to erosional scouring, productivity blooms, bottom current reworking, and bioturbation. At the 10-mile well spacing scale and greater, the data significantly overestimates intra-formational facies continuity but is successful in defining the following four-fold stratigraphy: The basal Pepper Shale is an argillaceous, moderate TOC, high CGR and GR mudrock. The Waller Member is a newly designated name used in this study for an argillaceous and foraminiferal, high TOC, massive mudrock with a generally moderate CGR and GR profile. The Bouldin Member is a high energy, carbonate-rich (foraminiferal), low TOC, low and variable CGR but high GR zone. Finally, the South Bosque Formation is an argillaceous and foraminiferal, moderate TOC, massive and laminated mudrock with a moderate CGR and GR signature. GR logs alone are inadequate for determination of facies, TOC content, depositional environment, and sequence stratigraphic implications. Using integrated lithologic, isotopic, and wireline log data, cored wells in the study area are correlated across the San Marcos Arch. Geochemical proxies (enrichment in Mo, Mn, U, and V/Cr) indicate that maximum basin restriction occurred during deposition of the Bouldin Member. Bottom current activity influenced depositional processes and carbonate sediment input was driven by water column productivity. These primary controls on Eagle Ford stratigraphy and character are independent from eustatic fluctuation, rendering classical sequence stratigraphy unreliable. / text

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

GIS (Geographic Information Systems) and remote sensing techniques were used to predict relationships between bald eagle nest presences and land type, distance to land type and impervious surface cover area. Data plots revealed bald eagle nest presence decreases in response to an increase in area of bareland; increases with an increase in area of forested land; decreases with an increase in distance (m) to shoreline, and decreases in response to an increase in area of impervious surfaces. Logistic regression models identified impervious surfaces as an indicator for bald eagle nest presence (P 24% as unsuitable. Unsuitable area covered 17.82% of the total study area, impacted area covered 13.40%, and, sensitive area covered 68.77%. The projected increase in population in the state of Virginia and subsequent increase in impervious surfaces presents a challenge to the future viability of the Virginia Chesapeake Bay bald eagle population. The threshold analysis identified areas of prime conservation concern for bald eagle nest presence within the defined study area. These areas provide the basis for a conservation management plan and for further scientific study.

Influence of historic landscapes and contemporary species management on Chesapeake Bay Bald Eagles and Osprey Catherine B. Viverette Co-distributed species with well documented demographic histories can provide good models for testing alternative hypotheses about the impact of evolutionary history, contemporary landscapes, and species management on current distribution and population structure. The Osprey (Pandion haliaetus) and Bald Eagle (Haliaeetus leucocephalus) have been extensively studied, managed and monitored across their North American breeding range, particularly in the Chesapeake Bay. We used a combination of ecological niche modelling, diet reconstruction, and population genetic modeling to understand the role of historic events--both shallow and deep time--on contemporary species distribution. The first objective of this study was to develop contemporary and paleo-distributional models for North American Bald Eagles and Osprey in order to explore the geographic histories of the two species, including the identity of possible Pleistocene refugia. Potential distribution during past (e.g. Last Glacial Maximum, LGM) and possible future climate scenarios were developed with species occurrence records for Osprey (n = 3034) and Bald Eagles (n = 8859) combined with 19 bioclimatic variables representing current conditions using the maximum entropy model (MaxEnt). Paleoclimatic models predict multiple putative refugia that may explain differences in migratory behavior between the two currently co-distributed species, as well as geographically defined sub-populations within each species. We conducted bulk stable isotope analysis of feathers collected from museum specimens and contemporary nests to investigate the influence of historic declines in critical prey species on distribution of Bald Eagles (n = 41 ) and Osprey (n = 45) in the Chesapeake Bay over the past 140 y. Stable Isotope Analysis in R (SIAR) was used to estimate the relative contribution of potential prey items in order to test the hypothesis that migration of estuarine-dependent and anadromous clupeid fishes represents an historically important seasonal subsidy in the form of marine-derived organic matter (MDOM). SIAR results demonstrate that MDOM contributed approximately 50% of the carbon and nutrients to Bald Eagle and Osprey occupying the upper estuary historically but declined to less than 5% of contemporary diets. Declines in anadromous prey in the diet correspond with historic spatial shifts in distribution and population growth of avian predators over the same period. Finally, we tested the hypothesis that conservation efforts, specifically translocation or “hacking” programs, rather than biogeographical history, best explains the current pattern of genetic variation exhibited by Osprey across their North American breeding range. We genotyped 11 microsatellite loci and a 513 base pair sequence of the cyt b region from 433 Osprey samples in order to investigate current population substructure, the genetic consequences of historic demographic bottlenecks, and the influence of hacking programs on contemporary gene flow. We calculated genetic differentiation (Dest) and Isolation-By-Distance (IBD) among regional populations and spatially cohesive genetic clusters identified using the program STRUCTURE. Our results indicate that although Osprey nesting in North America are subdivided into multiple cohesive genetic clusters, genetic differentiation among groups is low and unrelated to geographic variation. The findings of this study are discussed in light of past and present management practices and broader issues salient to species management and conservation of genetic diversity and adaptive response to future environmental change.

Elasmobranchs play ecologically important roles in coastal environments. Unfortunately, the basic distribution and movement patterns of these species, particularly rays, remain relatively unknown. This is especially true for the Whitespotted Eagle Ray (Aetobatus narinari), a protected species in Florida with poorly described migratory and habitat use patterns. I employed a combination of acoustic telemetry techniques to reveal multi-scale spatial patterns of A. narinari around Florida. Movement patterns between the east and west coast individuals were distinct; a majority of west coast tagged A. narinari exhibited migratory or transient behavior while most east coast tagged individuals remained resident in the Indian River Lagoon. Fine-scale tracking of A. narinari revealed individuals spent a large percentage of time in the inlets and channels and frequently reused habitats parallel to the shore. This study fills a knowledge gap on the species ecology which may be used for adaptive management strategies throughout A. narinari’s range. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2018. / FAU Electronic Theses and Dissertations Collection

The martial eagle (Polemaetus bellicosus) is a vulnerable species that is declining throughout large portions of its range. There is an urgent need to improve understanding of this species’ ecology to inform its conservation. I equipped 20 adult martial eagles with global positioning system backpack transmitters to characterize diet and space use of the species in the Maasai Mara region of Kenya. The resulting high-resolution transmitter data sets allowed for the rapid location of kills and provided a means to estimate home range size. From November 2016 to April 2018, 191 kills were identified from 206 kill location visits. Martial eagle diet comprised 26 prey species of which hares (two Lepus species, 17.3%), impala fawns (Aepyceros melampus, 13.6%) and helmeted guineafowl (Numida meleagris, 12%) were the most numerous. Sex-based differences in diet were found, with females selecting for heavier prey items (p < 0.001). The average 95% kernel density estimated home range for the duration-of-transmitter-placement (average of 372 days) was 174.5 ± 83.2 km2, a much larger estimate than previously reported. This study is the most extensive to date on martial eagle diet and spatial ecology in eastern Africa, and the first to show dietary differences between the sexes.

This collection of stories is based on the author’s experiences as a middle school teacher at an alternative campus in south Texas, in a district whose population was largely comprised of Mexican-American and low-income families. The Eagle School is based on a program that existed in the 1990s to address the special needs of “bubble” students, children who were failing in elementary school because of factors such as poverty, neglect, and violence at home. Students were selected for the program based on recommendations from their counselors, with the hope that the small campus of twelve teachers would provide its 150 sixth, seventh, and eighth graders with a safe haven, allowing them to focusing on their studies. The ultimate goals of the program were to prevent students from dropping out of school and to engage them in interdisciplinary projects that would advance them academically, preparing them to return to their appropriate grade levels in high school. Ms. Russel, a character based on the author, recounts stories of her efforts to help students at the Eagle School, as well as stories of her own friendships, aspirations, and disappointments off campus. Each story represents a distinct moment during the six years that she teaches at the Eagle School, and each focuses on a specific student or group of students whose conflicts complicate her own.