A Test for Extending the High-Resolution Global Climate Record in Santa Barbara Basin

ODP Site 893 in Santa Barbara Basin recovered high-resolution global climate data extending back to ∼160 ka at 200 m sub-seafloor. Safety concerns though have prevented deeper drilling at this site. Santa Barbara Basin is, however, tectonically active. As a result, continuous late-Quaternary strata deposited in the deep paleo-bathymetric basin were uplifted and folded across the Mid-Channel Trend, and strata as old as ∼450 ka (OIS 12) appear to be exposed at the seafloor where they are now accessible to piston coring. This project will test the accessibility along the anticline of these older stratigraphic sequences through detailed basin correlation of high-resolution seismic stratigraphy and subsequent coring. In preparation for coring in summer 2005, grids of high-resolution MMS analog, industry multichannel, and 2D USGS high-resolution seismic reflection data (collected in 2002) are being used to correlate dated reference horizons at ∼120 ka, ∼160 ka and ∼1 Ma along with several intervening seismic sequence boundaries across the Mid-Channel Trend. Results provide the basis for modeling the structure and stratigraphy in 3D, and to precisely locate suitable sites for coring. Subsequent core analyses will be used to verify the predicted outcrop pattern and basin-wide sequence stratigraphic interpretation. Thus, in addition to its contributions to Quaternary climate history, this project will help document the nature and evolution of the Mid-Channel anticline, and the local interaction between tectonics, climate, and sea-level change. To date, our results show that the Mid-Channel Trend has propagated from east to west as previously proposed. South of Santa Barbara harbor, folding on the anticline began about 1 Ma, while 10 km farther west, folding began after ∼450 ka. Furthermore, our results confirm that older strata (extending back to inferred OIS 12) of the paleo-Santa Barbara Basin have been folded, and are present at or near the seafloor.