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The Application Of Biostratigraphy And Paleoecology At Southern Ocean Drill Sites To Resolve Early To Middle Miocene Paleoclimatic Events, Ryan Farmer
Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research
The diatom biostratigraphy and paleoceanography of Ocean Drilling Program (ODP) Site 744 on the Southern Kerguelen Plateau, southern Indian Ocean are documented for the early to middle Miocene to improve chronostratigraphic age control for the Southern Ocean and Antarctic region. Paleoenvironmental fluctuations in the Southern Ocean are inferred from changes in fossil diatom abundance, preservation, and assemblage composition. A robust, new age model for Holes 744A and 744B is constructed using Constrained Optimization (CONOP) model ages for diatom biostratigraphic datum levels and new magnetic polarity data, which enables assessment of a nearly continuous record of paleoenvironmental change from ~20.25 to …
Using Electrical Resistivity Imaging To Map Saline Groundwater And Subaqueous Spring Discharge: An Example From The Saline Wetlands Of Eastern Nebraska, Bridget B. Kelly
Using Electrical Resistivity Imaging To Map Saline Groundwater And Subaqueous Spring Discharge: An Example From The Saline Wetlands Of Eastern Nebraska, Bridget B. Kelly
Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research
In order to better understand saline groundwater distribution and discharge dynamics within the saline wetlands of eastern Nebraska, electrical resistivity data were collected at three wetland sites within the Little Salt Creek Watershed. Electrical resistivity imaging (ERI) can provide an expanded understanding of saline groundwater distribution through the acquisition of a large number of resistivity measurements collected at the surface; upon inversion, the distribution of resistivity can be displayed in cross-section and subsurface processes serving to control salinity can be inferred. In recent years, several studies have used conventional methods of characterizing groundwater flow within the saline wetlands. These point …
Stratigraphic Analysis And Regional Correlation Of Isolated, Top-Truncated Shallow Marine Sandstone Bodies Within The Upper Cretaceous Frontier Formation, Bighorn And Washakie Counties, Wyoming, Andrew J. Hutsky
Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research
A detailed sedimentologic and stratigraphic analysis facilitated interpretations of depositional environment, sequence stratigraphy, and sandstone body geometry for isolated, top-truncated, shallow marine sandstone bodies of the Upper Cretaceous (Cenomanian-Turonian) Frontier Formation, northeast Bighorn Basin, Wyoming. The Frontier Formation interval is ~160 meters thick and was deposited as a complex clastic wedge that prograded into Cretaceous Western Interior Seaway (KWIS). The vertical interval comprises several incomplete coarsening-upward cycles, composed of basal offshore marine and prodeltaic shales progressively overlain by proximal shallow marine/fluvial facies that are capped by pebble lags. Sedimentary structures, vertical stacking patterns, and lateral variability within these cycles record …
New Stable Isotope Record Of Paleoecological Change In The Late Neogene Of The Western Great Plains From Enamel In Large Mammals, Zachary Kita
Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research
An expansion of C4 grasslands occurred between 6 and 8 million years ago in the Great Plains of North America, as evidenced by a marked shift to more 13C-enriched carbon isotope compositions from large fossil mammal tooth enamel and paleosol carbonates. Prior to this expansion, habitats were comprised of exclusively C3 vegetation. To explore this problem I present a compilation of bulk stable carbon (δ13C) and oxygen (δ18O) isotope values from a variety of large mammals from 6 localities that span from the late Clarendonian to the late Blancan in Nebraska. As expected, …