HR: 0800h
AN: GP21A-0018    [Abstracts]
TI: Late Brunhes Polarity Excursions and Sedimentation Patterns on the Eirik Drift (North Atlantic)
AU: * Evans, H F
EM: geohelen@ufl.edu
AF: Department of Geological Sciences, University of Florida, 241 Williamson Hall, PO Box 112120, Gainesville, FL 32611 United States
AU: Wright, J D
EM: jdwright@rci.rutgers.edu
AF: Department of Geological Sciences, Rutgers University, Wright Laboratories, Piscataway, NJ 08854 United States
AU: Channell, J E
EM: jetc@geology.ufl.edu
AF: Department of Geological Sciences, University of Florida, 241 Williamson Hall, PO Box 112120, Gainesville, FL 32611 United States
AU: Stoner, J S
EM: jstoner@coas.oregonstate.edu
AF: College of Oceanic and Atmospheric Sciences (COAS), Oregon State University 104 COAS Administration Building , Corvallis, OR 97331 United States
AU: Hillaire-Marcel, C
GP21A-0018 AF: GEOTOP, Universite du Quebec a Montreal, Montreal, Que H3C 3P8 Canada
AU: Mountain, G
GP21A-0018 AF: Department of Geological Sciences, Rutgers University, Wright Laboratories, Piscataway, NJ 08854 United States
AB: Eirik Drift is a constructive sedimentary feature off the southern tip of Greenland. The drift is 800 km long and has largely been constructed by the interaction of the roughly southwestward flowing Western Boundary Undercurrent (WBUC) and the basement topography. Jumbo piston cores and gravity cores were collected on Eirik Drift in the summer of 2002 during cruise KN166-14 of the RV Knorr. These cores, along with core MD99-2227 collected by the Marion Dufresne in 1999, have yielded new records of the Laschamp and Iceland Basin polarity excursions and information about the history of sedimentation on the Eirik Drift. Initial age models for the cores based on relative geomagnetic paleointensity proxies and oxygen isotope data indicate that the sedimentation rates vary between 3 cm/kyr and 28 cm/kyr. Magnetic grain size parameters and magnetic susceptibility show significant changes at the marine isotope stage 2/1 transition, marine isotope stage 6/5e transition and during marine isotope stages 7, 9 and 11 due to increased detrital material derived from the deglaciation of Greenland. Discrete cm scale layers with coarser grained magnetic material, high magnetic susceptibility and in some cases high percent carbonate values are seen in marine isotope stages (MIS) 2, 3, 4, 6, 7, 8, and 11. These are interpreted as being detrital carbonate (DC) and low detrital carbonate (LDC) events associated with Laurentide Ice Sheet (LIS) instability and/or input of detrital material from the deglaciation of Greenland. Ice advances that produced ice-rafted debris (IRD) are thought to have also triggered turbiditic flows in the North Atlantic Mid-Ocean Channel (NAMOC) resulting in the deposition of the DC and LDC layers on the deepest part of the Eirik Drift from sediment suspended by these flows.
DE: 1512 Environmental magnetism
DE: 1513 Geomagnetic excursions
DE: 1521 Paleointensity
SC: Geomagnetism and Paleomagnetism [GP]
MN: Fall Meeting 2005