Physical Sciences and Mathematics Commons^™

Conservation Limnogeology And Benthic Habitat Mapping In Central Lake Tanganyika (Tanzania), Joseph S. Lucas

Theses and Dissertations--Earth and Environmental Sciences

Small scale protected zones are valuable for helping the health and productivity of fisheries at Lake Tanganyika (East Africa). Spatial placement of protected areas relies on accurate maps of benthic habitats, consisting of detailed bathymetry data and information on lake-floor substrates. This information is unknown for most of Lake Tanganyika. Fish diversity is known to correlate with rocky substrates in ≤ 30 m water depth, which provide spawning grounds for littoral and pelagic species. These benthic habitats form important targets for protected areas, if they can be precisely located.

At the NMVA, echosounding defined the position of the 30-m isobath …

Occurrence And Attributes Of Two Echinoderm-Bearing Faunas From The Upper Mississippian (Chesterian; Lower Serpukhovian) Ramey Creek Member, Slade Formation, Eastern Kentucky, U.S.A., Ann Well Harris

Theses and Dissertations--Earth and Environmental Sciences

Well-preserved echinoderm faunas are rare in the fossil record, and when uncovered, understanding their occurrence can be useful in interpreting other faunas. In this study, two such faunas of the same age from separate localities in the shallow-marine Ramey Creek Member of the Slade Formation in the Upper Mississippian (Chesterian) rocks of eastern Kentucky are examined. Of the more than 5,000 fossil specimens from both localities, only 9–34 percent were echinoderms from 3–5 classes. Nine non-echinoderm (8 invertebrate and one vertebrate) classes occurred at both localities, but of these, bryozoans, brachiopods and sponges dominated. To understand the attributes of both …

Stratigraphy And Organic Geochemistry Reveal Patterns Of Late Quaternary Paleo-Productivity At Mono Lake, California, Bailee Nicole Hodelka

Theses and Dissertations--Earth and Environmental Sciences

Mono Lake (CA) is a hydrologically closed lacustrine basin well-known for its paleo-shorelines, which record fluctuations in water level for the last deglacial and late Holocene. Mono Lake is a sentinel of California’s water supply, situated in the rain shadow of the Sierra Nevada, a mountain range whose snowpack is a vital source of freshwater for urban and agricultural districts to the west and south. Recent droughts, floods, and wildfires show that California is threatened by climate change, but how these changes impact and get recorded by Mono Lake sediments remains poorly known. Here, we use a new radiocarbon-dated deepwater …

A Multi-Indicator Approach To Understanding The Diagenesis Of Carbonates In Pennsylvanian Mudrocks Of The Midland Basin, Alex J. Reis

Theses and Dissertations--Earth and Environmental Sciences

The Late Pennsylvanian was a time of frequent, rapid glacioeustatic sea-level changes. These changes were recorded in the Wolfcamp D Formation of the Midland Basin as a series of cyclothems similar to those studied in the Midcontinent region (e.g., Algeo and Heckel, 2008). This study focuses on identifying the mechanisms and controls on carbonate deposition and diagenesis through the Upper Pennsylvanian Wolfcamp D Formation and evaluating the potential for these layers to be stratigraphically significant. A stepwise progression of diagenetic processes was identified through the use of δ¹³C_carb and δ¹⁸O_carb, bulk geochemical and …

Geochronological And Geochemical Constraints On The Origin Of The Cartoogechaye Terrane, Western North Carolina: Implications For The Late Precambrian To Early Paleozoic Evolution Of The Eastern Laurentian Margin, Kevin B. Walsh Jr.

Theses and Dissertations--Earth and Environmental Sciences

The Cartoogechaye terrane (CT) is an enigmatic migmatite terrane within the Central Blue Ridge province of the southern Appalachians. Previous work identified exotic Pb isotope compositions within the CT (Quinn, 2012). More recent studies that mapped the extent of potentially exotic metaigneous lithologies yield U-Pb zircon ages consistent with a native Laurentian margin metasedimentary origin (Larkin, 2016). This study focused on the possible extent of similar lithologies in the Clyde quadrangle and provides further constraints on the crustal affinity of the CT. The Clyde quadrangle consists of four distinct lithologic packages: the CT, Ashe metamorphic suite, Great Smoky Group, and …

Hydrologic Monitoring And 2-D Electrical Resistivity Imaging For Joint Geophysical And Geotechnical Characterization Of Shallow Colluvial Landslides, Matthew M. Crawford

Theses and Dissertations--Earth and Environmental Sciences

Landslide characterization and hazard assessments require multidisciplinary approaches that connect geologic processes with geotechnical parameters. Field monitoring of hydrologic variables such as water content and water potential, coupled with geoelectrical measurements that can establish relationships used for geotechnical and landslide hazard investigations is deficient.

This study brings together different techniques to develop a methodology that connects geoelectrical measurements and shear strength. A field-based framework was established that includes (1) analysis of long-term soil moisture fluctuations within different landslides (2) establishment of constitutive and new equations that test the use of electrical conductivity to predict soil-water relationships and shear strength (3) …