Paper No. 17
Presentation Time: 9:00 AM-6:30 PM
PALYNOMORPHS INDICATE THAT ABRUPT INTERVALS OF WARMING INTERRUPTED GLACIATION IN THE ANTARCTIC MIOCENE
Understanding the sensitivity and cause(s) behind past climate change is important in developing an approach to current and future climate change. Previously published palynological data from the Antarctic indicate that the climate and vegetation in this region deteriorated through the late Paleogene and early Neogene, but with several recurring warm intervals in the Miocene (Warny and Askin, 2011; Warny and Askin, 2009). The driving force(s) behind these climate fluctuations is a highly debated topic, two popular theories being that the tectonic evolution around the continent led to reduced meridional heat transport (e.g. Kennett, 1977) or that changing levels of atmospheric CO2 drove the climate to cooler or warmer temperatures (e.g. Deconto and Pollard, 2003). Constraining changes in vegetation can help us to determine the cause(s) behind Antarctic, and indeed, global climate change. We exam Miocene Antarctic palynology of the ANDRILL 2 core to better understand these climate changes. At 1138.54 meters long, this core exhibits an extraordinary 98% recovery that spans the middle Miocene. Preliminary data from our study indicate an interval of increased palynomorph abundance at ~933 mbsf (~19.63 Mya, Acton et al., 2008). This section is dominated by two species of Nothofagus, a genus of southern beech, and may indicate increased moisture availability and warmer temperatures during this time. Data from the interval spanning ~800-997 mbsf indicates that this brief, warm interval interrupted intervals of glaciation prior to the Mid Miocene Climatic Optimum. Further exploration of this core will indicate if other warm intervals existed. Comparison to pCO2 data and other environmental proxies may help determine the likely cause(s) behind abrupt warm periods in Antarctica's glaciated past.