Geologic and Biologic Indicators of Climate Change in the Ross Sea, Antarctica
As of 2002, Degree of Master of Science (MS) Quaternary and Climate Studies published under the auspices of the Climate Change Institute.
The current interglacial, the Holocene, is a key time period for understanding global climate change, because climate variations occurred in the absence of large Northern Hemisphere ice sheets. Most of the research and our understanding of Holocene climate variability are derived from records that were collected in the Northern Hemisphere. The small number of Holocene records from the Southern Hemisphere limits our understanding about the timing and characteristics of climate events between the polar hemispheres that are crucial for discriminating among hypotheses of Holocene variability. Reconstructions of Holocene climate variability in Antarctica are rare and generally based on ice-core geochemistry. My goal is to develop a record of Holocene environmental change from the southern high latitudes, which will complement existing studies. The present study has two major objectives. The first is to determine the processes that created the raised beaches along the Southern Victoria Land coast (SVLC) to determine the oceanic environment at the time of their formation. The second is to compare my environmental reconstruction to the presence of southern elephant seals (SES) and Adelie penguins that colonized these beaches during the Holocene. My results indicate that all beaches along the SVLC were formed during storm events. My data indicates that during three intervals at 800 to 1700, 3300 to 3600 and 5250 to 6500 cal yr. BP, beaches were formed by more intense storms. There are two hypotheses to explain these phases. One is that a reduction in sea ice during these times allowed normal storms to leave the same geologic signature as more intense storms that occurred during times of extensive sea ice. This is because sea ice has a dampening effect on storm energy. The other possibility is that the more intense storms were the result of the movement of the polar vortex at times when the climate was in transition from a warm to a cold phase or vice versa. The geologic data from this study favors the latter interpretation, because there is no indication of an increase in wave activity that would accompany a reduction in sea ice during the three intervals discussed above. The comparison of my results with other Holocene climate records notably the temperature reconstruction from the nearby Taylor Dome ice core, indicates that these three phases correlate with shifts in the climate system.