Climate and environmental change following the retreat of the last glacial ice sheet in the Antarctic Peninsula has been interpreted, employing diatom abundance, relative abundance of Chaetoceros resting spores and diatom assemblages as proxies. These together with sedimentological data and radiocarbon dating, suggest four major events that can be further subdivided. Deglaciation ~13.2-11.5 kyr BP with ice shelf breakup and strong surface water stratification from melting ice. Climate reversal ~11.5-9.0 kyr BP with turbulent water masses. Climate optimum ~9.0-4.0 kyr BP with intrusions of northern ´warm` water masses. Neoglacial ~4.0 kyr BP-present with extended periods of sea ice cover and increased storm frequency. One aspect of climate change is the stability of marine based ice sheets, and the interaction with underlying sediment. A pilot study on characterizing sediment influenced by past ice streaming (Ross Sea) was performed using diatom, texture and chemical analysis. The results show that: Diamictons are chemically and texturally well homogenized, whereas diatom assemblages suggest different degrees of stratigraphic mixing and reworking related to mode of glacial sediment transport. Mud appears in different stratigraphic sections deposited in sub-ice shelf or ice edge environment, or through winnowing by currents. This is evident through stratigraphically-diverse diatom assemblages and texture. Most sediment characterized as mud is enriched in zinc (Zn). Hemipelagic diatomaceous muds are enriched in barium (Ba) and the diatom assemblage is dominated by typical neritic post-glacial species.
| Identifer | oai:union.ndltd.org:UPSALLA1/oai:DiVA.org:uu-1884 |
| Date | January 2002 |
| Creators | Sjunneskog, Charlotte |
| Publisher | Uppsala universitet, Institutionen för geovetenskaper, Uppsala : Acta Universitatis Upsaliensis |
| Source Sets | DiVA Archive at Upsalla University |
| Language | English |
| Detected Language | English |
| Type | Doctoral thesis, comprehensive summary, info:eu-repo/semantics/doctoralThesis, text |
| Format | application/pdf |
| Rights | info:eu-repo/semantics/openAccess |
| Relation | Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, 1104-232X ; 692 |
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