HR: 1340h
AN: PP13A-1021    [Abstracts]
TI: Foraminiferal Mn/Ca: Uncovering its Paleoproxy Potential
AU: * De Baere, B J
EM: bdebaere@coas.oregonstate.edu
AU: Klinkhammer, G P
EM: gklinkhammer@coas.oregonstate.edu
AU: Mix, A C
EM: mix@coas.oregonstate.edu
AB: College of Oceanic and Atmospheric Sciences, Oregon State University, Ocean Admin Bldg 104, Corvallis, OR 97331, United States of America. The flow-through time-resolved analysis (FT-TRA) technique for foraminiferal proxy work allows for the quantification of pristine biogenic elemental data, such as Mn/Ca, whilst disregarding overgrowth-induced signals. We used this state-of-the-art technique to carry out a core-top survey of the Mn/Ca ratios for surface dwelling foraminifera from across the world's oceans. This study revealed an oceanographically consistent pattern featuring order of magnitude variability, exactly what one would expect from the distribution of dissolved Mn in the mixed layer. Foraminifera at southern hemisphere sites have the lowest Mn/Ca ratios (~ 0.01) while those from the northern hemisphere are distinctly higher (~ 0.2). This pattern is strikingly similar in distribution and scale to variations in the atmospheric iron flux suggesting that foraminiferal Mn/Ca has potential as a paleoproxy for terrestrial input and productivity. The dust-dominated pattern at the surface together with the unique profile of Mn in the water column makes the Mn/Ca ratio of foraminiferal calcite a powerful new paleoproxy.
DE: 4801 Aerosols (0305, 4906)
DE: 4906 Aerosols (0305, 4801)
DE: 4924 Geochemical tracers
DE: 4994 Instruments and techniques
SC: Paleoceanography and Paleoclimatology [PP]
MN: 2007 Fall Meeting