Browsing by Subject "paleoclimate"

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Fluvial and Eolian Depositional Systems, Paleosols, and Paleoclimate: Late Cenozoic Ogallala and BlackWater Draw Formations, Southern High Plains, Texas and New Mexico
(1995) Gustavson, Thomas C.
The late Tertiary Ogallala Formation contains the Ogallala (High Plains) aquifer, which is the major source for water for agricultural and domestic use on the Southern High Plains of Texas and New Mexico and the overlying perched aquifers. This study, which is based on outcrop and subsurface data including both log and core information, was undertaken to provide regional geologic information necessary to evaluate and provide information for the Department of Energy's (DOE's) efforts to remediate contamination of the vadose zone and of the perched aquifer above the Ogallala aquifer at the DOE's Pantex Plant in eastern Carson County. Deposition of the basal fluvial sediments of the Ogallala Formation in northwestern Texas and eastern New Mexico was controlled by topography on the underlying erosional surface. Paleovalley-fill facies consist of heterogeneous gravelly and sandy ephemeral-stream deposits and sandy to clayey overbank deposits interbedded with and overlain by eolian sediments deposited as sand sheets and loess. Uplands on the pre-Ogallala erosional surface are overlain by similar eolian sediments. Buried calcic soils consisting mostly of CaCO3 nodules and filaments occur throughout the eolian facies.
Future Climatic and Envirornmental Conditions in the Texas Panhandle- A Geological Perspective
(1985) Caran, S. Christopher
Among the many factors to be considered in planning a high-level nuclear waste repository in northwestern Texas are future climatic conditions and their role in affecting environmental change. In future millennia, the regional climate will almost certainly undergo episodic variations comparable to those inferred from the paleoclimatic record of the late Quaternary Period. In addition, local and perhaps global weather patterns may change in ways not previously sustained, as a consequence of inadvertent and possibly deliberate human activities. If the scope and duration of these natural and induced climatic changes were significant, they would appreciably influence geomorphic and geohydrologic processes in the Texas Panhandle.
Phanerozoic Evolution Trends within Benthic Foraminifera
(2023) Faulkner, Katherine; Martindale, Rowan
Foraminifera are marine protists that evolved and diversified throughout the Phanerozoic Eon. These protists construct their shells (called “tests”) from their surrounding environment. Foraminifera tests fossilize in great abundance and are sensitive to ocean chemistry and climate. In this study, the relative proportions of calcareous and agglutinated foraminifera are used to understand changes in ocean chemistry over 541 million years. With this data, I aim to answer the following question: How have benthic foraminifera responded to short- and long-term changes in global ocean chemistry? This was accomplished by aggregating diversity-level information from Foraminifera Genera and their Classification, published by Alfred R. Loeblich and Helen Tappan, the most recent and commonly-used reference literature for foraminiferal genera. I built a dataset by recording the accepted names, wall type, and time interval of 3,114 taxa (2,442 genera). Using the genera, binned by Epoch, I tracked wall-type diversity, compared the ratios of calcareous versus agglutinated foraminifera, and contextualized foraminiferal responses to geologically-significant events. I found a notable decrease in relative abundance of calcareous foraminifera during the mid-Carboniferous warming and the end-Permian mass extinction. These changes in the Paleozoic imply that benthic calcifiers organisms were more sensitive to changing ocean acidification and temperatures. However, despite documented climatic fluctuations throughout the Cenozoic, calcareous foraminifera remain stable around 80% diversity from the Eocene through the Pleistocene. This implies benthic calcifiers were more resilient to changes in the Cenozoic, which may be due to pelagic calcifiers stabilizing the carbonate saturation. Comprehensive datasets such as this are essential for research about faunal diversity and paleoclimate records, ocean chemistry, and conservation because it provides insight into how benthic marine organisms respond to and interact with their marine environment. This data has the potential to inform global trends of benthic foraminifera and ocean chemistry throughout the Phanerozoic, which can contextualize current changes in the marine ecosystem.