Geosciences Graduate Student Publication Series

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  • Publication
    CO2 and tectonic controls on Antarctic climate and ice-sheet evolution in the mid-Miocene
    (2021-01-01) Halberstadt, Anna Ruth; Chorley, Hannah; Levy, Richard H.; Naish, Timothy; Deconto, Robert M.; Gasson, Edward; Kowalewski, Douglas E.
    Antarctic ice sheet and climate evolution during the mid-Miocene has direct relevance for understanding ice sheet (in)stability and the long-term response to elevated atmospheric CO2 in the future. Geologic records reconstruct major fluctuations in the volume and extent of marine and terrestrial ice during the mid-Miocene, revealing a dynamic Antarctic ice-sheet response to past climatic variations. We use an ensemble of climate – ice sheet – vegetation model simulations spanning a range of CO2 concentrations, Transantarctic Mountain uplift scenarios, and glacial/interglacial climatic conditions to identify climate and ice-sheet conditions consistent with Antarctic mid-Miocene terrestrial and marine geological records. We explore climatic variability at both continental and regional scales, focusing specifically on Victoria Land and Wilkes Land Basin regions using a high-resolution nested climate model over these domains. We find that peak warmth during the Miocene Climate Optimum is characterized by a thick terrestrial ice sheet receded from the coastline under high CO2 concentrations. During the Middle Miocene Climate Transition, CO2 episodically dropped below a threshold value for marine-based ice expansion. Comparison of model results with geologic data support ongoing Transantarctic Mountain uplift throughout the mid-Miocene. Modeled ice sheet dynamics over the Wilkes Land Basin were highly sensitive to CO2 concentrations. This work provides a continental-wide context for localized geologic paleoclimate and vegetation records, integrating multiple datasets to reconstruct snapshots of ice sheet and climatic conditions during a pivotal period in Earth's history.
  • Publication
    Time Scavengers: An Educational Website to Communicate Climate Change and Evolutionary Theory to the Public through Blogs, Web Pages, and Social Media Platforms
    (2019-01-01) Lam, Adriane R.; Bauer, Jennifer E.; Fraass, Susanna; Sheffield, Sarah; Limbeck, Maggie R.; Borden, Rose M.; Thompson-Munson, Megan E.; Fraass, Andrew J.; Hils, J. Michael; Muskelly, Cameron E.; Hartshorn, Kyle R.; Bryant, Raquel
    Climate change and evolution are topics at the forefront of political discussions, debates, and the public sphere. Regardless of evidence on both topics, the public as a whole still believes they are under debate. It is imperative that the public have access to correct and easy-to-digest information on these topics to make informed environmental and ecological decisions. To date, scientifically accurate digital platforms aimed at informing the public on these topics are overly complex and jargon-ridden. Time Scavengers ( was created to address these issues and is maintained by a group of academics, graduate students, avocational scientists, and educators. The site includes many informational pages about geology, climate change, and evolution, all written for the public with useful descriptions and figures. To make the process of science more transparent, the site includes blogs to provide insight into data collection and interpretation, field work, and public outreach. The site also includes additional pages with links to relevant content and activities appropriate for K-12 classrooms. The overarching goals of the site are to bridge the gap between scientists and the public through engaging, informational pages and personal experiences and to increase science literacy through easy-to-digest content.