<p>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 <i>Chaetoceros</i> resting spores and diatom assemblages as proxies. These together with sedimentological data and radiocarbon dating, suggest four major events that can be further subdivided.</p><p>Deglaciation ~13.2-11.5 kyr BP with ice shelf breakup and strong surface water stratification from melting ice. </p><p>Climate reversal ~11.5-9.0 kyr BP with turbulent water masses. </p><p>Climate optimum ~9.0-4.0 kyr BP with intrusions of northern ´warm` water masses. </p><p>Neoglacial ~4.0 kyr BP-present with extended periods of sea ice cover and increased storm frequency. </p><p>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:</p><p>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. </p><p>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). </p><p>Hemipelagic diatomaceous muds are enriched in barium (Ba) and the diatom assemblage is dominated by typical neritic post-glacial species.</p>
| Identifer | oai:union.ndltd.org:UPSALLA/oai:DiVA.org:uu-1884 |
| Date | January 2002 |
| Creators | Sjunneskog, Charlotte |
| Publisher | Uppsala University, Department of Earth Sciences, Uppsala : Acta Universitatis Upsaliensis |
| Source Sets | DiVA Archive at Upsalla University |
| Language | English |
| Detected Language | English |
| Type | Doctoral thesis, comprehensive summary, text |
| Relation | Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, 1104-232X ; 692 |
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