Glacial-to-interglacial changes of the ocean circulation and eolian sediment transport

Glacial-to-interglacial climate transitions are characterized by distinct basinwide sediment accumulation patterns that can reveal accompanying ocean circulation changes that occur during these transitions. A combination of an ocean global circulation model (OGCM) and a large-scale 3-D sediment transport model is used to model the global ocean thermohaline conveyor (THC) and distribution of the sedimentation rates for different time periods. Two different OGCM numerical mixing schemes are used to test the sensitivity of the sedimentation pattern to changes in model parameterizations of the thermohaline circulation, and especially the mixing technique. A sediment transport model is employed to identify glacial-to-interglacial changes of the deep-ocean currents. This model is suitable to identify the regions of the world ocean that are most responsive to the strong changes in glacial and interglacial circulation patterns and therefore are suitable for comparison of the computer simulations and geologic record. Two different eolian dust sources were prescribed at the sea surface: (1) A spatially homogeneous inorganic atmospheric dust source is used to depict sedimentation patterns that result only from the circulation changes. (2) A realistic present-day eolian dust pattern was specified in order to assess a more realistic sedimentation pattern. The results show that the modeled THC changes are traceable in the sediment accumulation patterns. These simulations indicate that the changes in sediment deposition rates are often associated with the changes in inter-basin water exchange, enabling verification of the simulated deep circulation using the geologic record.