HR: 14:40h
AN: U23A-05    [Abstracts]
TI: MIS 11 and the mid-Brunhes Dissolution Interval
AU: * Barker, S
EM: sbarker@ldeo.columbia.edu
AF: Lamont Doherty Earth Observatory of Columbia University, 61 Route 9W, Palisades, NY 10964 United States
AU: Elderfield, H
EM: he101@esc.cam.ac.uk
AF: Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge, CB2 3EQ United Kingdom
AU: Greaves, M
EM: mg109@esc.cam.ac.uk
AF: Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge, CB2 3EQ United Kingdom
AU: Booth, L
EM: lboo98@esc.cam.ac.uk
AF: Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge, CB2 3EQ United Kingdom
AU: Tripati, A
EM: atri02@esc.cam.ac.uk
AF: Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge, CB2 3EQ United Kingdom
AB: The mid-Brunhes dissolution interval (MBDI) represents a prolonged period of marine carbonate dissolution centred around Marine Isotope Stage 11 (MIS 11). The MBDI has been observed in all the major ocean basins and at all water depths. We present a 1Myr foraminiferal shell weight record from ODP site 982 in the North Atlantic (57.5N, 15.9W, 1134m) which is strongly affected by dissolution over this period, demonstrating the vulnerability of even shallow sites to the effects of dissolution. From a compilation of carbonate mass accumulation rates (MARs) we suggest that a global increase in marine carbonate production was responsible for the carbonate crash at this time. This is a variant on the basin to shelf hypothesis which argues that enhanced growth of shallow water carbonates in low latitudes during MIS 11 resulted in a global dissolution event. We model the effects of the proposed increase in carbonate production within the constraints of observed atmospheric CO2 variability.
DE: 4805 Biogeochemical cycles (1615)
DE: 4806 Carbon cycling
DE: 4825 Geochemistry
DE: 4267 Paleoceanography
SC: Union [U]
MN: 2004 AGU Fall Meeting