HR: 0800h
AN: C51B-0381    [Abstracts]
TI: Upper Pliocene Diatom Record From Northern Basin, Ross Sea; Potential Correlation to Other Antarctic Continental Shelf Records
AU: * Sjunneskog, C
EM: charlottems60@yahoo.com
AF: Louisiana State University, Dept. of Geology and Geophysics, Baton Rouge, La 70803, United States
AU: Bart, P
EM: pbart@lsu.edu
AF: Louisiana State University, Dept. of Geology and Geophysics, Baton Rouge, La 70803, United States
AU: Chow, J
EM: jchow1@lsu.edu
AF: Louisiana State University, Dept. of Geology and Geophysics, Baton Rouge, La 70803, United States
AU: Winter, D
EM: dwinter1@juno.com
AF: University of Nebraska - Lincoln, Department of Geosciences, 214 Bessey Hall, Lincoln, Ne 68588-034, United States
AU: Scherer, R
EM: t60rps1@wpo.cso.niu.edu
AF: Northern Illinois University, 3Department of Geology and Environmental Geosciences, 312 Davis Hall, DeKalb, Il 60115, United States
AU: ANDRILL MIS Project Science Team, A
EM: http://www.andrill.org
AF: ANDRILL, ANDRILL Science Management Office, 126 Bessey Hall, Lincoln, Ne 68588- 0341, United States
AB: The Northern Basin seismic record suggests a dynamic East Antarctic Ice Sheet with at least eight Late Neogene glacial expansions. The seismic-stratigraphic record indicates relatively thick late Neogene sequences on the outer continental shelf and upper slope and possibly undisturbed interglacial sequences. In 2003 Nathaniel B. Palmer (NBP03-01) collected 10 piston and jumbo piston cores in a depth transect from Mawson Bank to Drygalski Basin. The sediment cores range from 46 cm to over 4 meters in length, only recovering the surface of upper seismic unit. The lithologies of the cores include diatom mud, bioclastic sediment, silt, sand, clay and diamicton. Diatom analyses reveals that two of these cores, NBP03-01 PC2 and NBP03-01 PC8, have penetrated into undisturbed Upper Pliocene sequences. Upper Pliocene diatomaceous units are also recovered in Prydz Bay ODP sites 742 age ca. 1.8-2.2 Ma, and 1166 ages ca 1.8-2.2 and 2.5-2.8, sandwiched between diamictons. Recovery of Pliocene and Pleistocene sediment records of interglacial events is rare on the Antarctic continental shelf and the obtained records have been difficult to correlate with any certainty. With the recent recovery of the ANDRILL MIS (AND-1 core) the potential for correlation of these records has improved significantly. The sediment record from ANDRILL MIS comprises 13 diatomaceous units, all with their own specific diatom assemblage and key species. Comparison of diatom assemblages using key taxa and PCA show a strong correlation between Northern Basin PC2 and PC8, ODP Site 742 and MIS diatom unit IV placed at the Gauss-Matuyama boundary. Continued multiproxy analyses and independent dating will be performed to further constrain the correlation. The initial results have implications for regional correlation of interglacial events, and suggest that other Pliocene sediment records may be preserved in the Northern Basin region.
DE: 0726 Ice sheets
DE: 1616 Climate variability (1635, 3305, 3309, 4215, 4513)
DE: 4944 Micropaleontology (0459, 3030)
DE: 4950 Paleoecology
SC: Cryosphere [C]
MN: 2007 Fall Meeting