HR: 0800h
AN: PP21C-1581    [Abstracts]
TI: Time series analysis of ice-rafted debris accumulation in the Irminger basin, 0-630 ka
AU: * St. John, K E
EM: stjohnke@jmu.edu
AF: James Madison University, Dept of Geology and Env Sci MSC 7703, Harrisonburg, VA 22807 United States
AU: Thomley, J
EM: thomleyje@appstate.edu
AF: Appapachian State University, Dept of Mathematical Sciences, Boone, NC 28607 United States
AU: Westerhold, T
EM: tho@uni-bremen.de
AF: MARUM - University Bremen, Loebener Strasse PO Box 330 440, Bremen, 28334 Germany
AU: Flower, B
EM: bflower@marine.usf.edu
AF: University of South Florida, College of Marine Sciences 140 7th Ave South, St. Petersburg, FL 33701 United States
AU: Krissek, L
EM: krissek@mps.ohio-state.edu
AF: Ohio State University, Dept of Geological Sciences 125 S Oval Mall, Columbus, OH 43210 United States
AB: Recently published isotopic records and point count records of biogenic, volcanic and nonvolcanic terrigenous (ice-rafted debris; IRD) sediment components from ODP Hole 919A in the Irminger basin, northern North Atlantic, generated a comprehensive dataset and complicated climate signals from which general trends and developmental steps in the paleoceanographic reconstruction for the last 630 kyr were identified. To extract any rhythmic cycles embedded in this long term, unevenly-spaced dataset (avg. sample resolution of 1.3 kyr), spectral analyses of the oxygen isotope and IRD records were performed using SPECTRUM and REDFIT. Accounting for coring gaps, results show a dominant eccentricity cycle in the O-isotope record and an unexpected dominant half-precession cycle (11.5 kyr) in the IRD record. Obliquity frequencies are not robust and there is no precession frequency. Millennial pacing (3-7 kyr) of both records is observed when analyzing the complete time series and is confirmed in higher resolution intervals (e.g., last glacial, MIS 8), suggesting that suborbital patterns of climate change and IRD input to the Irminger basin extend back at least 300 kyr, and possibly 600 kyr.
DE: 3022 Marine sediments: processes and transport
DE: 3255 Spectral analysis (3205, 3280)
DE: 4910 Astronomical forcing
DE: 9325 Atlantic Ocean
SC: Paleoceanography and Paleoclimatology [PP]
MN: Fall Meeting 2005