Concrete planning continues for launching the IODP Arctic Ocean expedition in summer 2004. The two major objectives are (1) to understand the long-term (50 Ma) and short-term (Neogene) paleoceanographic history and (2) the tectonic evolution of the central Arctic Ocean.So far, the history of Arctic Ocean paleoceanography is so poorly known that scientists can look at the recovery of any material as a true exploration that will, by definition, increase the knowledge and understanding of this critical region for climate change. As an important contribution to the planned drilling in the central part of the Arctic Ocean, we have worked out a refined chronostratigraphy for Marine Isotope Stage (MIS) 16 to MIS 2 on existing ODP site 910 from the marginal Arctic Ocean (Yermak Plateau), which will serve as important correlating tools for establishing a sound stratigraphy in the central Arctic Ocean.Various approaches including sedimentological, physical and micropaleontological methods are needed to establish a chronostratigraphy for the central Arctic Ocean. However, low resolution and discontinuous records of biogenic material as well as equivocal interpretations of paleomagnetic records have limited the stratigraphic resolution so far. An elegant way for tackling these ongoing chronostratigraphic problems integrates various chronostratigraphic approaches to date records from the marginal eastern Arctic Ocean that underlies the submerging Atlantic-water derived intermediate waters. Once these records are exactly dated, they may provide useful stratigraphic reference sections for central Arctic Ocean records underlying the submerging Atlantic-water derived intermediate waters, like for example, the Lomonossov Ridge area.We chose the Yermak Plateau the Atlantic/Arctic Ocean gateway as key area for our study because, (1) here, rather than in central Arctic Ocean, carbonate bearing sequences permit establishment of a relatively continuous stable oxygen isotope stratigraphy, which is still the prerequisite for any subsequent application of chronological approaches, and (2) the dynamic coupling between the northernmost branch of the Gulf Stream and the Arctic Ocean. Up to now, the time resolution in ODP site 910 A is by far too low to address most relevant question in climate changes. Here, we verify the existing but equivocal age model of Hole 910A down to Marine Isotope Stage 16 by compiling new and existing chronostratigraphic age fix points in site 910A to strengthen the reliability of Arctic Ocean chronology and establish a new, fundamental basis for generating high-resolution paleoenvironmental reconstructions in the central Arctic Ocean.
Helmholtz Research Programs > MARCOPOLI (2004-2008) > POL6-Earth climate variability since the Pliocene