HR: 14:40h
AN: H53I-04    [Abstracts]
TI: Deriving a High-Resolution - Continuous Record of Climate Change for the Past 15,000 cal BP, Maxwell Bay Sediment Core, South Shetland Islands
AU: * Milliken, K T
EM: milliken@rice.edu
AF: Rice University, 6100 Main St. MS 126, Houston, TX 77005 United States
AU: Anderson, J B
EM: johna@rice.edu
AF: Rice University, 6100 Main St. MS 126, Houston, TX 77005 United States
AU: Wellner, J S
EM: jksmith@rice.edu
AF: Rice University, 6100 Main St. MS 126, Houston, TX 77005 United States
AU: Manley, P
EM: manley@middlebury.edu
AF: Middlebury College , McCardell Bicentennial Hall 427 , Middlebury, VT 05753 United States
AU: Bohaty, S
EM: sbohaty@es.ucsc.edu
AF: Univeristy of California Santa Cruz, 1156 High St., Santa Cruz, CA 95064 United States
AB: In the Antarctic Peninusla area, a climatic gradient, created by orographic and oceanographic effects, is manifested in extreme temperature and precipitation patterns. Thus, the area provides a natural laboratory to study the nature and timing of climate change at high southern latitudes during the past several thousand years. Two benchmark long term continuous records can now be compared; Maxwell Bay, situated in a warm wet subpolar climate setting and Palmer Deep, located in a cold wet subpolar climatic regime. Both of these records span the past 14000 years, document the LGM ice pullback and provide the means to contrast climate fluctuations in two different area. This paper presents the preliminary results from a 108 m sediment core (93 % recovery) recovered from Maxwell Bay (South Shetland islands). The pre-existing Palmer Deep cores sampled 50 m of structureless diatom ooze/mud, rhythmically interbedded diatom ooze and pebbly mud and muddy diatomicton (Domack et. al., 2001). The alternation of diatom ooze and diatomaceous mud is interpreted to represent climate driven oscillations of biogenic productivity. Magnetic susceptibility and other paleoenvironmental proxies track biogenic productivity and provide a means to quantify decadal, century, and millennia scales of climate change. Additionally, five global climate intervals are noted including, deglaciation, climatic reversal, Hypsithermal (Holocene Climatic Optimum), Neoglacial, and Little Ice Age. Several radiocarbon dates are used to establish an age model and show significant variations in sedimentation rates through time. The sedimentation rate variations correspond to sediment facies changes within the core. High sedimentation rates (10 to 30 mm/yr) correspond to silty diatomaceous mud with abundant sand laminae interpreted as proximal glaciomarine facies. Lower sedimentation rates (4 mm/yr) are associated with diatomaceous mud with few sand laminae and abundant bioturbation, interpreted to represent distal glaciomarine sedimentation. Preliminary analysis of magnetic susceptibility data shows decadal, century, and millennial scale cyclicity. Additionally, the character of the magnetic susceptibility signal changes within the core. The changes correspond to climate intervals noted in the Palmer Deep cores. Whereas the Palmer Deep record is derived from a biogenic productivity signal as a proxy for climate; the Maxwell Bay system potentially records a terrestrial sediment derived signal and is more directly linked to climatically driven glacial advance and retreat.
DE: 1616 Climate variability (1635, 3305, 3309, 4215, 4513)
DE: 1620 Climate dynamics (0429, 3309)
DE: 1637 Regional climate change
DE: 1861 Sedimentation (4863)
DE: 4863 Sedimentation (1861)
SC: Hydrology [H]
MN: Fall Meeting 2005