HR: 14:25h
AN: PP43C-04    [Abstracts]
TI: Integrating Recent Pleistocene Glacial Records From the Lomonosov Ridge, Central Arctic Ocean
AU: * O`Regan, M
EM: oregan@gso.uri.edu
AF: University of Rhode Island, Narragansett Bay Campus, Narragansett, RI 02882 United States
AU: Moran, K
EM: kate.moran@uri.edu
AF: University of Rhode Island, Narragansett Bay Campus, Narragansett, RI 02882 United States
AU: Backman, J
EM: backman@geo.su.se
AF: Stockholm University, Department of Geology and Geochemistry, Stockholm, 106 91 Sweden
AU: King, J
EM: jking@gso.uri.edu
AF: University of Rhode Island, Narragansett Bay Campus, Narragansett, RI 02882 United States
AU: Heil, C
EM: chip@gso.uri.edu
AF: University of Rhode Island, Narragansett Bay Campus, Narragansett, RI 02882 United States
AU: Jakobsson, M
EM: martin.jakobsson@geo.su.se
AF: Stockholm University, Department of Geology and Geochemistry, Stockholm, 106 91 Sweden
AB: Pleistocene sediments recovered from the Lomonosov Ridge in the central Arctic Ocean display distinctive brown color banding that is related to manganese (Mn) content and has been shown to follow glacial-interglacial cycles as recorded in the low latitude δ¹⁸O records [Jakobsson et al., 2000]. Combined with biostratigraphic and magnetostratigraphic data, these color changes provide an invaluable tool for developing a chronostratigraphic model for Central Arctic sediments. The current age model, based on core 96/12-PC, a 7.22 m long piston core recovered from the central Lomonosov Ridge in 1996 in a water depth of 1003 m, extends back to ca. 860 ka [Jakobsson et al., 2000]. In constructing this age model, the presence of the nannofossil Emiliana huxleyi was used to delineate OIS 5, while the first major downhole magnetic excursion was identified as the BIWA II event occurring in OIS 7 [Jakobsson et al., 2003]. Along a depth transect of drilling sites, the distance between these two marker horizons increases from 0.5 m in the 96/12-PC to 1.6 m in PS2185 and finally 3.8 m in sediment cores recovered during the recent Integrated Ocean Drilling Program's Arctic Coring Expedition [Backman et al., in press]. This suggests a dynamic depositional environment on the ridge crest and possibly a hiatus prior to the start of OIS 5e in the 96/12-PC. By integrating high-resolution magnetic and physical property measurements with discrete strength and consolidation tests, both the nature and extent of this unconformity are revealed. Results not only offer a glimpse into oceanographic conditions in the central Arctic during OIS 5 and 6, but provide a revised age model for advancing our understanding of glacial-interglacial cyclicity in the central Arctic Ocean.
UR: http://www.ecord.org/exp/acex/302.html
DE: 1605 Abrupt/rapid climate change (4901, 8408)
DE: 4926 Glacial
DE: 4936 Interglacial
SC: Paleoceanography and Paleoclimatology [PP]
MN: Fall Meeting 2005