Paleoenvironmental evolution of on-shore ice-free areas around Maxwell Bay, King George Island, South Shetlands Islands

• Main Author: Heredia Barión, Pablo Alfredo
• Other Authors: Spiegel, Cornelia, Kuhn, Gerhard, Melles, Martin
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: Universität Bremen 2019
• Subjects: Antarctic Peninsula; polar gravel beach; Holocene; deglaciation; exposure dating; radiocarbon dating; glacio-isostatic adjustment; Potter Peninsula; Fildes Peninsula; 550; 550 Earth sciences and geology; ddc:550; Antarctic; Fildes; Fildes peninsula; King George Island; Maxwell Bay; South Shetland Islands; Antarc*; Ice Sheet
• Online Access: https://media.suub.uni-bremen.de/handle/elib/1624; https://nbn-resolving.org/urn:nbn:de:gbv:46-00107475-15

Understanding the Holocene is particularly important for providing the context for recent ice sheet dynamics a i.e. understanding whether current ice sheet dynamics are unusual or part of Holocene natural variability (Bentley et al., 2014). Knowledge on the most recent millennia of Antarctic Ice Sheet history is vital for evaluating the response of the ice sheet to various forcing agents, such as sea-level rise, atmospheric and oceanographic temperature changes, and for constraining grounding-line retreat on Holocene to recent time scales (Bentley et al., 2014). The main objective of this thesis is to add new data to reconstruct the Holocene deglaciation history of King George Island, South Shetland Islands, northwest Antarctic Peninsula, by investigating morpho-sedimentary records of glacigenic and coastal landforms and associated sediments from the on-shore ice-free areas around Maxwell Bay (King George Island), namely Potter Peninsula and Fildes Peninsulas. In order to accomplish the thesis objectives, I used (i) cosmogenic exposure dating and radiocarbon dating for absolute chronological constraints; (ii) stratigraphy and sedimentology for relative chronological constraints and reconstruction of paleoenvironmental conditions; (iii) geomorphological mapping for spatial distribution of landsystems; (iv) and ground-penetrating radar (GPR) investigations for the study of internal sedimentary architecture of coastal landforms. Radiocarbon dating results yield new age constraints for the onset of deglaciation on Potter Peninsula, which occurred around at or before 7.8 ka cal BP instead of an earlier accepted age of 9.5 ka cal BP. I provide additional evidence for a short-lived glacier re-advance between 7.2 and 7.0 ka cal BP. This re-advance is likely linked to a glacier re-advance or still-stand documented on South Shetland Islands for that time period. Nevertheless, climatic conditions associated with this glacial re-advance remain unclear. In contrast, on Fildes Peninsula, exposure and radiocarbon dating ...