Sedimentology and geochemistry of the Iberian margin

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 <1 g cm**-2 ky**-1and a larger and variable clay input which indicates the importance of the sea level control on the clay input to the basin. Clay flux dominates the regional sediment accumulation which has a total flux of ~2 g cm**-2 ky**-1and a CaCO3 content up to 50% in interglacial times, and a total flux up to ~5 g cm**-2 ky**-1and a CaCO3 content down to 10% in glacial times.