A Palynological Analysis of Seymour Island and King George Island off the Antarctic Peninsula: A Dating and Climatic Reconstruction
During the Cretaceous and early Paleocene, Antarctica was covered by lush vegetation. However, Antarctica today is covered with ice and snow leaving less than 1% of the continent inhabited by vegetation. By studying this decline in vegetation and reconstructing past environments, we can gain a bette...
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LSU Digital Commons
2015
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| Online Access: | https://digitalcommons.lsu.edu/gradschool_theses/392 https://doi.org/10.31390/gradschool_theses.392 https://digitalcommons.lsu.edu/context/gradschool_theses/article/1391/viewcontent/uc.pdf |
| Summary: | During the Cretaceous and early Paleocene, Antarctica was covered by lush vegetation. However, Antarctica today is covered with ice and snow leaving less than 1% of the continent inhabited by vegetation. By studying this decline in vegetation and reconstructing past environments, we can gain a better understanding of environmental changes and use this knowledge to predict future changes. In this thesis, I present my results and interpretations of palynological changes across the Antarctic Peninsula during the Late Eocene, Middle Oligocene, and Miocene. The first study discusses a paleoenvironmental reconstruction of the upper La Meseta formation (Late Eocene), Seymour Island, and Polonez Cove formation (Middle Oligocene), King George Island. My results indicate a relatively decent abundance of in situ podocarp conifers and southern beech Nothofagidites (brassii, fusca, and menziesii gp.) palynomorphs present within the lower section of the studied La Meseta Formation. This implies the area was relatively free of ice and sparsely inhabited with a temperate-like forest in the Late Eocene. Progressing up section, the presence of sea-ice indicative acritarchs called Leiosphaeridia spp. and the dominance of cool-loving Nothofagidites sp. (fusca gp.) indicate a climate cooling as the region became more glaciated. Evidence of this cooling is more apparent based on the majority of palynomorphs which appear broken and the samples being dominated with Leiosphaeridia spp. in the upper most studied section of La Meseta formation and through the entire section of the Polonez Cove formation. Lastly, my second study discusses a palynological interpretation of Miocene samples collected from the Cape Melville formation on King George Island. The samples revealed a near-shore depositional environment dominated by sea-ice as indicated from the abundance of leiospheres. These samples are also dominated by various reworked palynomorphs of Permian to Paleogene age, mixed with rare in situ Miocene specimens. This study provides new ... |
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