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Full-Text Articles in Paleontology
Constraining Neogene Temperature And Precipitation Histories In The Central Great Plains Using The Fossil Record Of Alligator, Evan Whiting
Constraining Neogene Temperature And Precipitation Histories In The Central Great Plains Using The Fossil Record Of Alligator, Evan Whiting
Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research
Most amphibians and reptiles (excluding birds) are poikilothermic; their internal body temperature varies with that of their external environment. This makes them useful as climate proxies, especially when linked to geographic distributions of ambient climate. I evaluate the utility of the extant crocodylian genus Alligator as a paleoclimate proxy for the Central Great Plains (CGP) using species distribution modeling. Alligator is a readily identifiable taxon with a good CGP fossil record during the Neogene (~23–2.6 Ma). Alligator first appeared in the CGP in the late Eocene (~37 Ma), was absent during most of the Oligocene, reappeared in the early Miocene …
Body Size And Species Richness Changes In Glyptosaurinae (Squamata: Anguidae) Through Climatic Transitions Of The North American Cenozoic, Sara Elshafie
Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research
Poikilothermic vertebrates offer excellent climate proxies based on relationships between environment and measurable variables such as body size and species richness. Relationships of these variables in lizards to environmental transitions over long time scales are poorly understood. Here I show that patterns of body size and species richness in a lizard clade, Glyptosaurinae (Squamata: Anguidae), correspond to known histories of paleotemperatures through the Cenozoic of North America. Glyptosaurines have the richest fossil record among North American Cenozoic lizards and exhibit a wide range of skull sizes. In order to estimate body size for glyptosaurines and other fossil anguids, I collected …
Marine Diatom Assemblage Variation Across Pleistocene Glacial-Interglacial Transitions And Neogene Diatom Biostratigraphy Of Site C9001, Nw Pacific Ocean, Marcella K. Purkey
Marine Diatom Assemblage Variation Across Pleistocene Glacial-Interglacial Transitions And Neogene Diatom Biostratigraphy Of Site C9001, Nw Pacific Ocean, Marcella K. Purkey
Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research
In 2006, D/V-Chikyu cruise CK06-06 drilled Hole C9001C at Site C9001 in the Northwest Pacific Ocean, 80 km east of the Shimokita Peninsula, Japan. An existing chronostratigraphic framework provides a continuous glacial-interglacial (GI) climate record from which a diatom record of paleoenvironmental changes was developed across several GI cycles. Species counts, diatom temperature values, calculated sea-surface temperatures (SST) and factor analysis were produced for each sample and calibrated to prior diatom studies in this region. These features were used to characterize and compare interglacial maxima of Marine Isotope Stages (MIS) 1, 5e, 9 and 11 and transitions from the preceding …
Probable Glacial Climatic Conditions In Source Areas During Deposition Of Parts Of The Ash Hollow Formation, Ogallala Group (Late Tertiary), Of Western Nebraska, Patricia E. Helland, Robert F. Diffendal Jr.
Probable Glacial Climatic Conditions In Source Areas During Deposition Of Parts Of The Ash Hollow Formation, Ogallala Group (Late Tertiary), Of Western Nebraska, Patricia E. Helland, Robert F. Diffendal Jr.
Robert F. Diffendal, Jr., Publications
Evidence of the climatic conditions in the mountain sediment source areas for the late Tertiary Ash Hollow Formation of the Ogallala Group in western Nebraska has been sought in an SEM (scanning electron microscope) study of surface features on detrital quartz grains from these deposits. The following lines of indirect evidence raised the possibility of glacial conditions: uplift of up to 3500 m in the source areas, paleohydrologic parameters indicative of a transport system analogous to the modern North Saskatchewan River, and possible cold climate surface features on cobbles from the deposits. SEM analysis shows that five of the nine …