Changes in Climate and Moisture Availability in the Antarctic Eocene, Oligocene, and Miocene: Evidence from Palynological and Stable Isotope Geochemical Analyses of the SHALDRIL and ANDRILL Cores
Prior to the Late Eocene, the Antarctic continent experienced lush vegetation under temperate conditions. Just before the Eocene/Oligocene Boundary, the climate of the southernmost continent began to deteriorate dramatically. This cooling trend largely continued until most Antarctic vegetation disap...
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ftlouisianastuir:oai:digitalcommons.lsu.edu:gradschool_dissertations-2518 2023-06-11T04:06:10+02:00 Changes in Climate and Moisture Availability in the Antarctic Eocene, Oligocene, and Miocene: Evidence from Palynological and Stable Isotope Geochemical Analyses of the SHALDRIL and ANDRILL Cores Griener, Kathryn Whitney 2014-01-01T08:00:00Z application/pdf https://digitalcommons.lsu.edu/gradschool_dissertations/1519 https://doi.org/10.31390/gradschool_dissertations.1519 https://digitalcommons.lsu.edu/context/gradschool_dissertations/article/2518/viewcontent/uc.pdf unknown LSU Digital Commons https://digitalcommons.lsu.edu/gradschool_dissertations/1519 doi:10.31390/gradschool_dissertations.1519 https://digitalcommons.lsu.edu/context/gradschool_dissertations/article/2518/viewcontent/uc.pdf LSU Doctoral Dissertations climate palynology Miocene Oligocene Eocene moisture availability paleoclimatology Nothofagus Antarctica Nothofagidites d13C pollen Earth Sciences text 2014 ftlouisianastuir https://doi.org/10.31390/gradschool_dissertations.1519 2023-05-28T19:09:04Z Prior to the Late Eocene, the Antarctic continent experienced lush vegetation under temperate conditions. Just before the Eocene/Oligocene Boundary, the climate of the southernmost continent began to deteriorate dramatically. This cooling trend largely continued until most Antarctic vegetation disappeared, ~13.85-12.8 Ma. Classifying the nature and cause of Antarctica’s drastic climate change is essential for furthering our knowledge of Earth’s history, and also for grasping the potential effects of current and future climate shifts. Here, I present evidence from three new palynomorph-centric studies that deepen our understanding of Antarctic earth science, climate change, and of climate proxies. The first study involved analyzing the stable carbon isotopes (δ13C) of Nothofagidites fusca palynomorphs from the Late Eocene, Antarctic Peninsula region. We found that pollen Δ13C generally decreased through time, just prior to the Eocene/Oligocene Boundary, suggesting a decrease in water availability to plants. This decrease in moisture availability was likely caused by increased glaciation, decreased run off, decreased precipitation, or a combination of these factors. In the second study, the potential for using Nothofagus sp. pollen size as a proxy for changes in moisture availability was assessed. We found a significant relationship between pollen grain size and precipitation (as precipitation decreased, pollen size increased), suggesting this is a viable method for studying climate change. We then applied this method to Antarctic Eocene, Oligocene, and Miocene fossil Nothofagidites lachlaniae pollen and observed an overall increasing trend in pollen grain size from the Eocene through the Early Miocene, indicating that precipitation was decreasing in Antarctica during this time, and coincident with increased glaciation and decreased palynomorph abundance. Lastly, a standard palynological analysis was conducted on the lower sections of the ANDRILL 2A core from the Middle Miocene. Palynomorph abundance and diversity ... Text Antarc* Antarctic Antarctic Peninsula Antarctica LSU Digital Commons (Louisiana State University) Antarctic The Antarctic Antarctic Peninsula |
institution |
Open Polar |
collection |
LSU Digital Commons (Louisiana State University) |
op_collection_id |
ftlouisianastuir |
language |
unknown |
topic |
climate palynology Miocene Oligocene Eocene moisture availability paleoclimatology Nothofagus Antarctica Nothofagidites d13C pollen Earth Sciences |
spellingShingle |
climate palynology Miocene Oligocene Eocene moisture availability paleoclimatology Nothofagus Antarctica Nothofagidites d13C pollen Earth Sciences Griener, Kathryn Whitney Changes in Climate and Moisture Availability in the Antarctic Eocene, Oligocene, and Miocene: Evidence from Palynological and Stable Isotope Geochemical Analyses of the SHALDRIL and ANDRILL Cores |
topic_facet |
climate palynology Miocene Oligocene Eocene moisture availability paleoclimatology Nothofagus Antarctica Nothofagidites d13C pollen Earth Sciences |
description |
Prior to the Late Eocene, the Antarctic continent experienced lush vegetation under temperate conditions. Just before the Eocene/Oligocene Boundary, the climate of the southernmost continent began to deteriorate dramatically. This cooling trend largely continued until most Antarctic vegetation disappeared, ~13.85-12.8 Ma. Classifying the nature and cause of Antarctica’s drastic climate change is essential for furthering our knowledge of Earth’s history, and also for grasping the potential effects of current and future climate shifts. Here, I present evidence from three new palynomorph-centric studies that deepen our understanding of Antarctic earth science, climate change, and of climate proxies. The first study involved analyzing the stable carbon isotopes (δ13C) of Nothofagidites fusca palynomorphs from the Late Eocene, Antarctic Peninsula region. We found that pollen Δ13C generally decreased through time, just prior to the Eocene/Oligocene Boundary, suggesting a decrease in water availability to plants. This decrease in moisture availability was likely caused by increased glaciation, decreased run off, decreased precipitation, or a combination of these factors. In the second study, the potential for using Nothofagus sp. pollen size as a proxy for changes in moisture availability was assessed. We found a significant relationship between pollen grain size and precipitation (as precipitation decreased, pollen size increased), suggesting this is a viable method for studying climate change. We then applied this method to Antarctic Eocene, Oligocene, and Miocene fossil Nothofagidites lachlaniae pollen and observed an overall increasing trend in pollen grain size from the Eocene through the Early Miocene, indicating that precipitation was decreasing in Antarctica during this time, and coincident with increased glaciation and decreased palynomorph abundance. Lastly, a standard palynological analysis was conducted on the lower sections of the ANDRILL 2A core from the Middle Miocene. Palynomorph abundance and diversity ... |
format |
Text |
author |
Griener, Kathryn Whitney |
author_facet |
Griener, Kathryn Whitney |
author_sort |
Griener, Kathryn Whitney |
title |
Changes in Climate and Moisture Availability in the Antarctic Eocene, Oligocene, and Miocene: Evidence from Palynological and Stable Isotope Geochemical Analyses of the SHALDRIL and ANDRILL Cores |
title_short |
Changes in Climate and Moisture Availability in the Antarctic Eocene, Oligocene, and Miocene: Evidence from Palynological and Stable Isotope Geochemical Analyses of the SHALDRIL and ANDRILL Cores |
title_full |
Changes in Climate and Moisture Availability in the Antarctic Eocene, Oligocene, and Miocene: Evidence from Palynological and Stable Isotope Geochemical Analyses of the SHALDRIL and ANDRILL Cores |
title_fullStr |
Changes in Climate and Moisture Availability in the Antarctic Eocene, Oligocene, and Miocene: Evidence from Palynological and Stable Isotope Geochemical Analyses of the SHALDRIL and ANDRILL Cores |
title_full_unstemmed |
Changes in Climate and Moisture Availability in the Antarctic Eocene, Oligocene, and Miocene: Evidence from Palynological and Stable Isotope Geochemical Analyses of the SHALDRIL and ANDRILL Cores |
title_sort |
changes in climate and moisture availability in the antarctic eocene, oligocene, and miocene: evidence from palynological and stable isotope geochemical analyses of the shaldril and andrill cores |
publisher |
LSU Digital Commons |
publishDate |
2014 |
url |
https://digitalcommons.lsu.edu/gradschool_dissertations/1519 https://doi.org/10.31390/gradschool_dissertations.1519 https://digitalcommons.lsu.edu/context/gradschool_dissertations/article/2518/viewcontent/uc.pdf |
geographic |
Antarctic The Antarctic Antarctic Peninsula |
geographic_facet |
Antarctic The Antarctic Antarctic Peninsula |
genre |
Antarc* Antarctic Antarctic Peninsula Antarctica |
genre_facet |
Antarc* Antarctic Antarctic Peninsula Antarctica |
op_source |
LSU Doctoral Dissertations |
op_relation |
https://digitalcommons.lsu.edu/gradschool_dissertations/1519 doi:10.31390/gradschool_dissertations.1519 https://digitalcommons.lsu.edu/context/gradschool_dissertations/article/2518/viewcontent/uc.pdf |
op_doi |
https://doi.org/10.31390/gradschool_dissertations.1519 |
_version_ |
1768377977442140160 |