Paleoproductivity and Paleoclimate Reconstructions during Present and Past (MIS 11 and MIS 19) Interglacials in the SW Iberian Margin

Abstract:

Climate is changing significantly in the last decades affecting the global environment and population. Natural events and human activities are believed to contribute to this trend. Differentiating natural from anthropogenic forcing on the climate system is one of the major challenges of future climate prediction. For evaluating the natural climate evolution and anthropogenic contribution to the present-day interglacial, it is of extreme importance to compare the Holocene to a large set of older interglacial periods to better understand the natural climate variability. In order to better understand the climatic and productivity conditions during past interglacials we are studying Marine Isotope Stage 19 and 11, in the recently collected SW Iberian margin sequence of Site U1385, the Shackleton site from IODP Expedition 339. Interglacials occurring at 780 ka (MIS 19) and 420 ka (MIS 11) are, in terms of orbital configuration, the closest analogues to the present interglacial, and we expect, therefore, that the understanding of these interglacials instabilities will provide crucial information on the dynamics of the ongoing climate. In this study we present records for the past sea surface temperature based in U^k’₃₇-SST, paleo-productivity derivate from total alkenone and total organic carbon and continental input reconstructions at orbital, millennial and sub-millennial scales. The results show warmest conditions during the oldest interglacials, but similar Ocean Primary Productivity pattern during past and present Interglacial.