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Late Pleistocene And Holocene Hydroclimate Change In The Southeastern United States: Sedimentary, Pedogenic, And Stable Carbon Isotope Evidence In Tennessee River Floodplain Paleosols, James Joseph Kocis

Masters Theses

In order to understand hydroclimate variability of future climate change, it is important to know the timing and range of natural climate change in the past. The Southeastern United States (SE) is situated along the poleward extent of projected subtropical drying, where the expression of past hydrological balances remains unclear. The lack of high-resolution paleohydroclimate records in the SE forces climate modelers to base interpretations on better-understood regions of North America. The SE likely experienced significant changes in precipitation regimes resulting from its position at the convergence of several oceanic and continental air masses. To reconstruct precipitation variability, this study …

Structural And Stratigraphic Relationships Near The Southern Terminus Of The Pulaski Fault, Northeast Tennessee, Phillip Michael Derryberry

Masters Theses

The Pulaski fault is one of the master thrust faults in the Appalachian Alleghanian fold-thrust belt. Detailed geologic mapping of Cambrian and Ordovician strata in northeastern Tennessee revealed key structural and stratigraphic characteristics for distinguishing the Pulaski thrust sheet from its footwall, the Saltville thrust sheet. Unlike most thrust systems in the Valley and Ridge, the Pulaski records at least two deformation phases. Geometric and crosscutting relationships along parts of the Pulaski thrust sheet in this study area and in southwestern Virginia suggest hanging wall and possibly some footwall deformation prior to the emplacement of the thrust sheet. The initial …

Aeolian Simulations: A Comparison Of Numerical And Experimental Results, With Projections For Titan., Oscar Lee Mathews

Masters Theses

Aeolian processes are major determinants of geomorphology on bodies in the Solar System possessing an atmosphere-surface interface and transportable sediment, including Earth, Mars, Venus, and Titan. Substantial efforts have been made over the last few decades to understand these processes using specialized wind tunnels, field studies, and, more recently, numerical simulations. This thesis describes a model of aeolian sediment transport using computational fluid dynamics (CFD), and compares the results with those obtained in the Martian Surface Wind Tunnel (MARSWIT) testing conducted in the Planetary Aeolian Laboratory at NASA Ames Research Center. The ultimate goal of the thesis was to develop …

Processes Controlling The Composition Of First-Cycle Sediments Deposited In An Arid-Climate, With Implications For Provenance Reconstruction Studies, Aubrey Lynn Modi

Masters Theses

Petrologic analysis of first-cycle clastic sediments derived from a single source in an arid environment provides a means to determine how well they resemble the petrology and geochemistry of their source. The Stepladder Mountains, located in the Mojave Desert of southeastern California, represents a well-controlled location (i.e., arid environment; single, known source; short transport distance) to examine how naturally formed sediments acquire their compositions. Compositional modifications associated with sediment production were resolved through direct examination of the weathered components (regolith, grus, and sediments). Sediment compositions strongly vary by grain size, indicating that, after the source itself, hydrodynamic sorting played the …

Petrology And Geochemistry Of Olivine-Bearing Diogenites And A Group Of Paired Howardites, Andrew William Beck

Doctoral Dissertations

Asteroid 4 Vesta, the largest differentiated body in the asteroid belt, is a protoplanet, much like those that accreted to form the Earth. Understanding the geology of Vesta furthers understanding of early differentiation processes that occurred on Earth and helps define igneous processes occurring on other differentiated bodies in the early solar system. Howardite, eucrite and diogenite (HED) meteorites, which are thought to have originated from Vesta, can be analyzed to better understand the geology of that asteroid. Here my colleagues and I investigate the petrology and geochemistry of two groups of HEDs. This work is timely, in that the …

Remote Sensing Of Sediments And Volatiles On The Martian Surface And Terrestrial Analog Sites, Craig James Hardgrove

Doctoral Dissertations

The role of water and volatiles in the solar system is of critical interest in planetary science. Evidence for the past action of water or direct observation of water on a planetary body can indicate the potential to harbor life and is critical to human exploration of the solar system. We study two very different remote sensing techniques that address the issue of identifying water-related processes on the surface of other planetary bodies, and in particular, Mars. The first technique, combined thermal infrared and visible imaging, has been used extensively on Mars for determining the thermal inertia of surface materials. …

Carbon And Sulfur Cycling In Early Paleozoic Oceans, Cara Kim Thompson

Doctoral Dissertations

Here, I evaluate biospheric evolution during the Ordovician using high-resolution inorganic carbon and sulfur (carbonate-associated sulfate and pyrite) isotope profiles for Early Ordovician to early Late Ordovician strata from geographically distant sections in Western Newfoundland and the Argentine Precordillera. Additionally, I present new, high-resolution U-Pb ages for volcanic ash beds within strata of the Argentine Precordillera. Carbon isotope data record subdued variation that is typical of Early- to Middle Ordovician strata worldwide. By contrast, sulfur-isotopic compositions of carbonate-associated sulfate reveal a complex signal of short-term, rhythmic variation superimposed over a longer-term signal. This short-term, rhythmic variation occurs in all sections …

A Prospective Analysis On The Sustainability Of The Great Smoky Mountains National Park, Austin Bailey Porter

Chancellor’s Honors Program Projects

No abstract provided.

Sedimentologic And Stratigraphic Analysis Of Units Defining The Basal Sauk Supersequence Across The Craton Margin Hinge Zone, Southeastern California, Eric Gordon Hogan

Masters Theses

In the Death Valley and Mojave Desert regions of southeastern California, the contact separating the lower and middle members of the Wood Canyon Formation (WCF) is currently interpreted as a regional scale unconformity coincident with the base of the Sauk Sequence. Regional mapping of this surface, however, reveals a nonconformable contact with underlying crystalline basement in cratonic settings, and a relatively conformable contact atop a northwest thickening wedge of miogeoclinal strata that is capped by the lower member of the WCF. Consistent with an unconformity, the progressive loss of three carbonate units within the lower member of the WCF has …

Constraining Martian Sedimentation Via Analysis Of Stratal Packaging, Intracrater Layered Deposits, Arabia Terra, Mars, Sarah Beth Cadieux

Masters Theses

Craters within Arabia Terra, Mars, contain hundreds of meters of layered strata

showing systematic alternation between slope- and cliff-forming units, suggesting either

rhythmic deposition of distinct lithologies or lithologies that experienced differential

cementation. Hypothesized origins of these intercrater layered deposits include

lacustrine, aeolian, volcanic airfall, and impact surge deposition. On Earth, rhythmically

deposited strata can be examined in terms of stratal packaging, wherein the interplay of

tectonics, sediment deposition, and change in base level results in predictable patterns

with respect to changes in the amount of space available for sediment accumulation.

Fundamental differences between tectonic regimes of Earth and Mars …