Pleistocene variability of the Subtropical Convergence at East Tasman Plateau - Evidence from planktonic foraminiferal Mg/Ca (ODP Site 1172A)

摘要: Combined measurements of Mg/Ca and stable oxygen isotopes in tests the planktonic foraminifer G. bulloides from Ocean Drilling Program (ODP) Site 1172A (East Tasman Plateau) allowed us to reconstruct sea surface temperature (SSTMg/Ca), sea salinity (SSS), hence variations Subtropical Convergence (STC) southwestern Sea over last four major glacial-interglacial changes. During interglacials commonly enhanced SSTMg/Ca SSS correspond a lowered marine productivity and terrigenous flux, implying that STC separating cool, high-nutrient Subantarctic Surface Water warm, saline, oligotrophic Subtropical Surface Water band zonal westerlies responsible for eolian dust flux were located south East Plateau. The warm Australian Current was well established during periods propagated far south. During glacial times, SSTMg/Ca and lower, while both productivity increased. Such conditions prevailed during Marine Isotope Stages MIS 12, 10, lesser degree 6 implied extended northward influence SurfaceWater shift <44�S. overall climatic signal at appears be largely attenuated when compared published climate records comparable latitudes west east. amplitudes more pronounced subantarctic Indian Ocean at Chatham Rise. They exhibit consistent pattern suggesting latitudinal shifts STC occurred synchronously Indian Rise but damped at East Plateau due Australian Current.