A synthesis of magnetostratigraphic results from Pliocene‐Pleistocene sediments cored using the hydraulic piston corer

Abstract

We present a summary evaluation of the distribution and qualitative ranking of the Plio‐Pleistocene magnetostratigraphic results obtained to date from Deep Sea Drilling Project and Ocean Drilling Program piston‐cored sites. A review of the published magnetostratigraphic records provides insights into the important extrinsic and intrinsic factors which affect the quality of the paleomagnetic records. The extrinsic factors originate with drilling processes, such as core barrel remagnetization, and steps can be taken to reduce these effects and improve the data quality. The distribution of the high‐quality records correlates well both with areas of terrigenous sediment input as well as regions of moderate biological productivity. This suggests that important intrinsic factors include the origin of the original magnetic carrier in the sediment (lithogenic or biogenic) and the degree to which the magnetic carrier has been affected by reduction diagenesis.

Astronomically calibrated ages for geomagnetic reversals within the Matuyama chron

“…As part of the Deep Sea Drilling Project (DSDP) and the Ocean Drilling Program (ODP), hydraulic and advanced hydraulic piston corers have been used to obtain mechanically undisturbed Plio-Pleistocene sediments for paleomagnetic studies. Among the numerous cores recovered in the past two decades, less than 30% contain clear polarity zonations (Clement et al, 1996), and only a few have yielded long and detailed oxygen isotope records back into the Pliocene (e.g., DSDP Site 607 and ODP Sites 677 and 846; Ruddiman et al, 1989;Raymo et al, 1989;Shackleton et al, 1990Shackleton et al, , 1995. So far, the most widely referenced Plio-Pleistocene time scale (0-2.6 Ma) derived from astronomically tuned δ 18 O records is from ODP Site 677 (Shackleton et al, 1990), because its age estimates for the last major geomagnetic reversals have been confirmed not only by other independent astronomical ages (Hilgen, 1991) but also by high-precision 40 Ar/ 39 Ar dating on lava flows (Berggren et al, 1995 and references therein).…”