Changes in the depositional flux of ¹⁰Be in the Orca Basin, Gulf of Mexico: inverse correlation with δ¹⁸O

Abstract

We report a statistically significant negative correlation between the concentration (and the deposition rate) of the cosmogenic radionuclide ¹⁰Be and δ¹⁸O (of Globigerinoides ruber) in the sediments deposited in the anoxic Orca Basin (OB) of the Gulf of Mexico during the past ~20 ka. Possible causes for this finding consecutively include: (1) enrichment of ¹⁰ Be in the soils/easily erodable crustal material which were discharged into the OB during the Late Wisconsin Interglacial; (2) introduction of significant amounts of ¹⁰Be into the oceans due to the melting of continental ice sheets resulting in the enrichment of the radionuclide in the sediments deposited during that time; and (3) generation of a focussing effect resulting in the ¹⁰Be enrichment of the OB sediment.