Implications for sedimentation changes on the Iberian margin over the last two glacial/interglacial transitions from (230Thexcess)0 systematics

Abstract The Portuguese margin is well-suited for studies of the contrasts in North Atlantic circulation during glacial and interglacial times because of its rapid sediment accumulation rate. This paper reports a (230Thexcess)0-based study of sediment accumulation over the past 140 ky, a period which includes the last two glacial/interglacial transitions, in two cores at 2.4 and 3.5 km water depth on a slope transect at 40°N. Although the independently-determined mean sediment accumulation fluxes over the past 140 ky are unequivocally high with means of 13.2 and 10.5 g cm−2 ky−1 in the two cores, conventional application of the (230Thexcess)0 method yields consistently lower fluxes with means of 3.5 and 3.8 g cm−2 ky−1. These (230Thexcess)0 estimates are interpreted as representations of the regional depositional flux through time. This (230Thexcess)0 regional flux is composed of a carbonate flux of

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