Late Pleistocene chronostratigraphy and biostratigraphy of Mentelle Basin and its implications for global correlation

Abstract

An accurate and high-resolution age model in marine sediments is essential for reconstructing past oceanographic and climate changes. The southeastern Indian Ocean is an important component of oceanographic circulation and global climate. However, the integrated biostratigraphy for the Late Pleistocene interval is not well known in the region. To address this issue, we constructed a new chronology for International Ocean Discovery Program (IODP) Hole U1516B in the Mentelle Basin, offshore southwestern Australia. We employ planktonic foraminifera δ18O to construct an astronomically tuned age model for Hole U1516B. Biostratigraphic analysis was performed for Hole U1516B using planktonic foraminifera, nannofossils, radiolarian taxa and diatoms. Seven planktonic foraminifera events are recorded, including the PT1a and PT1b boundaries. Eight nannofossil events were recorded including the boundaries between CN14a, CN14b and CN15. The planktonic foraminifera datums marked in Hole U1516B are mostly synchronous with datums reported in the southern hemisphere but are diachronous with datums in the northern hemisphere. The nannofossil datums marked in Hole U1516B have a close affinity with globally reported datums but small inconsistencies are probably due to strong ecological control. The diatom events are inconsistent and only recorded in short intervals during interglacials and several key radiolarians taxa are absent.