Data–model integration for the Miocene: the need for more ocean drilling

Abstract

It is clear that the Miocene is a key interval to understand how earth systems interact to maintain global warmth, especially since carbon-based greenhouse gases may not have been extremely elevated at that time. It is also much easier, potentially, to study the Miocene than earlier intervals of global warmth because more complete sedimentary sections exist. To be studied, however, the sediment sections need to be sampled. In the oceans, the Miocene is sampled by the Integrated Ocean Drilling Program and its predecessors (Ocean Drilling Program and Deep Sea Drilling Project).Marine sedimentary records need to be gathered from the oceans at a scale to resolve the temperature evolution of the major surface water masses and transition regions. New drilling targeted to study the Miocene must occur to achieve this distribution. With existing ODP and DSDP cores it is possible to sample and study general trends over the Miocene, but it is only possible to study the early and middle Miocene in high resolution for a few ocean areas. Pelagic Miocene sections as a rule tend to be buried deeply below the surface and have not been cored adequately to make composite sediment columns needed for detailed studies.In the Pacific, for example, there is relatively good coverage to the middle-late Miocene boundary (~12Ma) but continuous sedimentary sections that cover the early and middle Miocene are relatively rare. Ironically, there are relatively good new data from the Pacific subtropical gyres, but information from the equatorial region and the high latitudes is lacking. A new site survey (AMAT-03) and a scheduled IODP drilling program have produced a strategy to measure a continuous 50 million year record of the equatorial Pacific Ocean. Similar programs are needed for other representative regions of the ocean and ocean gateways