BUILDING A COMMON STRATIGRAPHY FOR CONTINENTS AND OCEANS: PROGRESS ALONG THE CALIFORNIA MARGIN FROM ODP LEG 167

There is scientific interest to develop a common stratigraphy for continents and oceans along the California margin because of the strong influence of the North Pacific Ocean on the climate of western North America. Without a common high-resolution stratigraphy it has been difficult to decipher the importance of regional North Pacific influences separate from global ice volume effects. Up until Ocean Drilling Program Leg 167, developing this stratigraphy has been hampered by the lack of appropriate marine sediments for much of the Pleistocene. The continuous recovery of high sedimentation rate sections on ODP Leg 167 allows the possibility to intercalibrate terrestrial sequences with marine oxygen isotope stratigraphy.

A variety of techniques are now being applied on Leg 167 sediments to tie land and oceans. They include the use of oxygen isotope stratigraphy on the ODP sediments to date prominent ash layers recovered there, development of oxygen isotope-calibrated pollen stratigraphy for the coastal region, high-resolution paleomagnetic intensity stratigraphy, and comparing changes in North Pacific sea surface temperature to important climate change on land.

With iterations, it should be possible to build a common high-resolution stratigraphy along the western margin of North America for the Pliocene and Pleistocene. Because of the age of ocean crust off western North America and plate tectonic motions of the Pacific plate relative to North America, the maximum age that we will be able to tie directly is probably middle Miocene.