Located at a strategic position between low and mid-latitude borderlands, and between monsoonal and NAO influenced climate systems, the Mediterranean is an important site for a continuous paleoclimate record over at least one Glacial-Interglacial interval ( > 100 kyr BP). Such records are extremely difficult to get because of bioturbation, degradation, and dissolution. The two sites now explored by us, seem to be perfect high-resolution climate recorders, in particular the near-coastal site having a high-frequency 11-yr climate cycle for the thusfar recovered last 4.000 years. Preliminary studies have revealed that similar cycles occur at the deep anoxic basin sites were we also aim to complete an uninterrupted 11-year sediment trap time series. This, together with satellite and other observations, will permit us to unravel the actual mechanisms underlying the observed 11-year cycles in the sediments. Initial results indicate that temperature and salinity play a dominant role, which may lead to changes in land-derived fluxes but also in changes of biogenic, primary productivity related, marine fluxes. Comparison of the deep-ocean anoxic basin sites to the near-coastal sediments will allow to unravel near-coastal land-ocean interaction dominated signals from typical deep-ocean signals.
It is important to assess if the 11-year cycles continue into older (> 20 kyr) units at both sites; these depths can only be obtained using IODP drilling. Before such proposal can be submitted we need to have more certainty on the continuous nature of the laminations in sediments older than a few kyrs, in particular for sediments from the Last Glacial Maximum. In addition, we wish to calibrate potential new proxies so as to make them applicable to older units. Assessing the origin and mechanisms of the observed variations is needed to evaluate their potential functioning in more remote time periods such as may be recovered using IODP drilling.
Project Leader:
Professor Gert De Lange
Utrecht University, The Netherlands
Principal Investigators:
Professor Stefano Bernasconi
ETH-Zentrum, Zurich, Switzerland
Dr. Gerard Versteegh
University of Bremen, Germany
Dr. Karin Zonneveld
University of Bremen, Germany
