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Coherent Late-Holocene Climate-Driven Shifts In The Structure Of Three Rocky Mountain Lakes, Jeffrey R. Stone, Jasmine E. Saros, Gregory T. Pederson
Coherent Late-Holocene Climate-Driven Shifts In The Structure Of Three Rocky Mountain Lakes, Jeffrey R. Stone, Jasmine E. Saros, Gregory T. Pederson
United States Geological Survey: Staff Publications
Large-scale atmospheric pressure centers, such as the Aleutian and Icelandic Low, have a demonstrated relationship with physical lake characteristics in contemporary monitoring studies, but the responses to these phenomena are rarely observed in lake records. We observe coherent changes in the stratification patterns of three deep (>30 m) lakes inferred from fossil diatom assemblages as a response to shifts in the location and intensity of the Aleutian Low and compare these changes with similar long-term changes observed in the 18O record from the Yukon. Specifically, these records indicate that between 3.2 and 1.4 ka, the Aleutian Low shifted …
Filling The Gaps: A Comprehensive Understanding Of Diets And Ecosystem Interactions Within The Modern And Fossil Small Mammal Communities Of Meade Basin, Kansas, Hannah Richardson, Kena Fox-Dobbs, Andrew Haveles
Filling The Gaps: A Comprehensive Understanding Of Diets And Ecosystem Interactions Within The Modern And Fossil Small Mammal Communities Of Meade Basin, Kansas, Hannah Richardson, Kena Fox-Dobbs, Andrew Haveles
Summer Research
The modern Great Plains ecosystem began shifting from a woodland biome to a grassland in the Miocene. Stable isotope analysis (SIA) of a diverse community of local consumers, in this case small mammals, provides both a paleoenvironmental record of the shift from woodland C3 biomass to grassland C4 biomass, and a paleoecological record of species interactions and community dynamics. The Meade Basin in southwestern Kansas contains a rich and fairly complete fossil record of a Great Plains small mammal community throughout the past 5 million years. SIA of fossil tooth enamel from Meade small mammals has revealed interesting …
Cyclostratigraphy And Sedimentation Of The Cenomanian-Turonian Tuscaloosa Marine Shale, Christian Gilbert Kunhardt
Cyclostratigraphy And Sedimentation Of The Cenomanian-Turonian Tuscaloosa Marine Shale, Christian Gilbert Kunhardt
Electronic Theses and Dissertations
A cyclostratigraphic and geochemical analysis was conducted on the basal high resistivity zone of the Tuscaloosa Marine Shale to determine if orbital forcing is apparent in mineralogical data suites. Geochemical data suites obtained via x-ray diffraction from five cored wells located near the southern Mississippi/Louisiana border were used in the study. The results were used in concert with previously published insolation and biostratigraphic data and unpublished stable carbon isotope data to determine sedimentation rate, to identify and correlate the cretaceous oceanic anoxic event 2 (OAE 2) recovery period within the studied interval, and to determine the possible mechanisms of orbital …
Palynological Studies Of Holocene Lake Sediments In The Missouri Ozarks, Robert D. Haselwander
Palynological Studies Of Holocene Lake Sediments In The Missouri Ozarks, Robert D. Haselwander
Doctoral Dissertations
"Five small lakes in southeast Missouri (Frisco, Pine Forest, and Bray Area lakes [Phelps County], and Cypress and Blue ponds [Bollinger County]) were cored for paleolimnological studies. Cores were evaluated for their sedimentology, palynology, and geochemistry. In two of these lakes (Bray Area and Pine Forest lakes) the planktonic algae were also studied in the water column, along with ecological parameters. Algae in the sediments were compared to algae in the water to understand the resistance of different species to decay, and a suggested methodology for this work is described. Reconstructions of the past environments around each lake were created …