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Full-Text Articles in Physical Sciences and Mathematics

Biostratigraphic Revision Of Esthonyx (Tillidontia, Mammalia) In The Contect Of Climate Change In The Lower Eocene Of The Bighorn Basin, Wyoming, John Colter Johnson Jul 2024

Biostratigraphic Revision Of Esthonyx (Tillidontia, Mammalia) In The Contect Of Climate Change In The Lower Eocene Of The Bighorn Basin, Wyoming, John Colter Johnson

Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research

Esthonyx is an early Eocene tillodont found in North America, Europe, and India. The genus was named by Edward Drinker (E. D.) Cope in 1874 based on specimens from the San Jose Formation in New Mexico. Since then, several species of Esthonyx have been described from North America alone. The best record of Esthonyx comes from the central Bighorn Basin (BHB) in Wyoming, where it appears in 220 localities in a 640 m-thick stratigraphic succession. Since the last summary of Esthonyx in the BHB, several hundred new specimens have been collected and curated at the Denver Museum of Nature and …


Holocene Evolution Of Parabolic Dunes, White River Badlands, South Dakota, Usa, Revealed By High-Resolution Mapping, Paul Evans Baldauf, Gregory S. Baker, Maraina Miles, Patrick Burkhart, Allen Gontz, Madeline Rinka, Michael Levenson Jan 2023

Holocene Evolution Of Parabolic Dunes, White River Badlands, South Dakota, Usa, Revealed By High-Resolution Mapping, Paul Evans Baldauf, Gregory S. Baker, Maraina Miles, Patrick Burkhart, Allen Gontz, Madeline Rinka, Michael Levenson

Marine & Environmental Sciences Faculty Articles

The White River Badlands (WRB) of South Dakota record eolian activity spanning the late Pleistocene through the latest Holocene (21 ka to modern), reflecting the effects of the last glacial period and Holocene climate fluctuations (Holocene Thermal Maximum, Medieval Climate Anomaly, and Little Ice Age). The WRB dune fields are important paleoclimate indicators in an area of the Great Plains with few climate proxies. The goal of this study is to use 1 m/pixel-resolution digital elevation models from drone imagery to distinguish Early to Middle Holocene parabolic dunes from Late Holocene parabolic dunes. Results indicate that relative ages of dunes …


Ecometric Estimation Of Present And Past Climate Of North America Using Crown Heights Of Rodents And Lagomorphs: With Application To The Middle Miocene Climatic Optimum, Julia Schap May 2019

Ecometric Estimation Of Present And Past Climate Of North America Using Crown Heights Of Rodents And Lagomorphs: With Application To The Middle Miocene Climatic Optimum, Julia Schap

Electronic Theses and Dissertations

Continental scale studies on ungulate crown heights in relation to climate and habitat changes have revealed a correlation between increasing hypsodonty and a shift to more arid environments. Small mammals have been shown to adapt to changing habitats millions of years earlier than larger mammals. In this study I examined fossil localities throughout the last 37 Ma across North America. Diversity of rodents and lagomorphs were analyzed through this time period, with examination of community structure characterized by relative percentages of taxa with different crown heights. Overall, a decrease in precipitation and temperature was found across North America from 37 …


From Sea To Lake: The Depositional History Of Saint Albans Bay, Vt, Usa, Matthew Kraft Jan 2018

From Sea To Lake: The Depositional History Of Saint Albans Bay, Vt, Usa, Matthew Kraft

Graduate College Dissertations and Theses

Sediment accumulated in lakes stores valuable information about past environments and paleoclimatological conditions. Cores previously obtained from Saint Albans Bay, located in the Northeast Arm of Lake Champlain, VT record the transition from the Champlain Sea to Lake Champlain. Belrose (2015) documented the presence of a peat horizon separating the sediments of the Champlain Sea from those of Lake Champlain. Initially, this layer was thought to comprise the transition from the marine environment of the Champlain Sea to a freshwater wetland. However, based on the results from this study, the transition between marine and freshwater conditions is thought to be …


Constraining Neogene Temperature And Precipitation Histories In The Central Great Plains Using The Fossil Record Of Alligator, Evan Whiting Apr 2016

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 …


Aptian To Santonian Foraminiferal Biostratigraphy And Paleoenvironmental Change In The Sverdrup Basin As Revealed At Glacier Fiord, Axel Heiberg Island, Canadian Arctic Archipelago, Claudia J. Schröder-Adams, Jens O. Herrle, Ashton F. Embry, James W. Haggart, Jennifer M. Galloway, Adam T. Pugh, David M. Harwood Nov 2014

Aptian To Santonian Foraminiferal Biostratigraphy And Paleoenvironmental Change In The Sverdrup Basin As Revealed At Glacier Fiord, Axel Heiberg Island, Canadian Arctic Archipelago, Claudia J. Schröder-Adams, Jens O. Herrle, Ashton F. Embry, James W. Haggart, Jennifer M. Galloway, Adam T. Pugh, David M. Harwood

ANDRILL Research and Publications

Exceptional exposures of a High Arctic Cretaceous sedimentary record were studied at Glacier Fiord, Axel Heiberg Island. The succession reveals a complex Aptian to Santonian paleoenvironmental history of the Sverdrup Basin that documents several global events. Foraminiferal faunas in combination with rare macrofossil occurrences permit the distinction of nine zones that facilitate biostratigraphic correlations to other High Arctic locales, the Beaufort Mackenzie Basin and the Western Interior Sea. The depositional environment as exposed in the Christopher, Hassel, Bastion Ridge and Kanguk formations changed frequently from a shelf to a shoreface setting. Most sequence boundaries appear to be conformable where shoaling …


Paleoclimate From Corals, Helen V. Mcgregor Jan 2011

Paleoclimate From Corals, Helen V. Mcgregor

Faculty of Science - Papers (Archive)

Ocean- atmosphere interactions in the tropics have farreaching conscqucnccs for climate variabi lity across the globe. The tropics drive heat transfer to the poles, and tropical inter-annual oscillations such as the El Nino-Southern Oscillation (ENSO) and Indian Ocean dipole (IOD), via atmospheric tcleconncctions, affcct rain rail patterns and climate conditions in arcas far bcyond the tropics (Ropelewski and Halpert, 1987), causing major socioeconomic impacts. Monitoring eIT0l1s have focused on improving obscrvations and undcrstanding of tropical climate variability, with the view to refining modeling or the tropical oceans and atmosphere. Despite these efforts, most instrumcntal records span only the past few …


The Occurrence Of Forest Plants In The Desert Mountains Of Mongolia And Their Bearing On The History Of The Climate, Eckehart Johannes Jäger Jan 2005

The Occurrence Of Forest Plants In The Desert Mountains Of Mongolia And Their Bearing On The History Of The Climate, Eckehart Johannes Jäger

Erforschung biologischer Ressourcen der Mongolei / Exploration into the Biological Resources of Mongolia, ISSN 0440-1298

The isolated occurrences of forest plants in the desert mountains of southern Mongolia raise questions as to the mode of their dispersal and the age and direction of former range connections. For species without a possibility of long distance dispersal, a once continuous distribution over the southern Mongolian mountain chains must be assumed. To the Gurvan Saykhan mountains, the forest plants immigrated from the west. Nevertheless their distribution types are eastern Asiatic, or else Eurasiatic with an eastern center of gravity. This shows that the seasonal type of the recent climate with summer rains in eastern Asia influences vegetation composition. …


Diagenesis And Geochemistry Of Porites Corals From Papua New Guinea: Implications For Paleoclimate Reconstruction, Helen V. Mcgregor, M Gagan Jan 2003

Diagenesis And Geochemistry Of Porites Corals From Papua New Guinea: Implications For Paleoclimate Reconstruction, Helen V. Mcgregor, M Gagan

Faculty of Science - Papers (Archive)

No abstract provided.