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Full-Text Articles in Stratigraphy

Precambrian Molar-Tooth Structure: Unraveling The Diagenesis Of Ancient Carbonates, Agustin Kriscautzky Aug 2022

Precambrian Molar-Tooth Structure: Unraveling The Diagenesis Of Ancient Carbonates, Agustin Kriscautzky

Doctoral Dissertations

Molar-tooth structure (MTS) is an enigmatic carbonate fabric that occurs mainly within Proterozoic carbonate host rocks. It is composed of two distinct features: cracks of various morphologies and crack-filling calcite microspar. Although the origins of MTS remain unknown, most previous investigation has focused on the formation of the cracks and mechanisms involved in the void space generation, with less emphasis on the intriguing carbonate fill. In this study I have investigated molar-tooth bearing carbonates from regions that span both paleogeography and geologic time. Analysis at the microscopic scale, including traditional petrography, cathodoluminescence petrography, scanning electron microscopy, and micrometer-scale geochemical analyses …


Architectural-Element Analysis And Depositional Models For Pre-Vegetation Braidplain And Braid-Delta Environments, With Modern Analogues, Jason Gerhard Muhlbauer May 2021

Architectural-Element Analysis And Depositional Models For Pre-Vegetation Braidplain And Braid-Delta Environments, With Modern Analogues, Jason Gerhard Muhlbauer

Doctoral Dissertations

Pre-vegetation landscapes that blanketed the continents before the emergence vascular plants in the late-Silurian are proposed habitats for the earliest terrestrial biota and are analogous to martian setting thought to have potentially hosted life. Analysis of the middle member of the Wood Canyon Formation, a Cambrian age sandstone, reveal new details about terrestrial pre-vegetation environments. In fluvial middle-member stratigraphy, units are defined by stacking patterns of three facies associations (FA1-3). In FA1, stacked cosets, interpreted as braidplain barforms and channel fills, preserve vertical- and downstream-accretion elements under unimodal paleoflow. Floodplains, represented by FA2, include red-orange intervals of fine- to medium-grained …


Evidence Of Late Quaternary Fires From Charcoal And Siliceous Aggregates In Lake Sediments In The Eastern U.S.A., Joanne P. Ballard Aug 2015

Evidence Of Late Quaternary Fires From Charcoal And Siliceous Aggregates In Lake Sediments In The Eastern U.S.A., Joanne P. Ballard

Doctoral Dissertations

The late-glacial transition to the Holocene, 15,000–11,600 cal yr BP, is an enigmatic period of dynamic global changes and a major extinction event in North America. Fire is an agent of disturbance that transforms the environment physically and chemically, and affects plant community composition. To improve understanding of the linkages between fire, vegetation, and climate over the late glacial and Holocene in the eastern U.S., I analyzed lake-sediment cores for charcoal and indicators of wood ash, and compared results to existing pollen records. A new microscopic charcoal record from Anderson Pond, Tennessee revealed high fire activity from 23,000–15,000 cal yr …


Hydrogeology Of The Little River Animal Agriculture Environmental Research Unit And Impacts Of Dairy Operations On Groundwater, Robert Wesley Hunter Dec 2013

Hydrogeology Of The Little River Animal Agriculture Environmental Research Unit And Impacts Of Dairy Operations On Groundwater, Robert Wesley Hunter

Masters Theses

This thesis describes the development of an integrated hydrogeologic/hydrologic site assessment and groundwater/surface water quality monitoring program at the University of Tennessee – Little River Dairy Farm, located near Townsend, TN. Hydrologic/hydrogeologic investigations of streams and groundwater at the site have been underway for more than 5 years, and these are expected to provide background data for assessing impacts of dairy wastes. The lower half of the ~180 ha site consists of low-relief fields used for row crops, which are underlain by 4 – 9 m of alluvial deposits on top of black shale or limestone that include sinkhole features. …


Structural And Stratigraphic Relationships Near The Southern Terminus Of The Pulaski Fault, Northeast Tennessee, Phillip Michael Derryberry Dec 2011

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 …


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 Dec 2011

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 …