Calcareous nannofossil biomagneochronology of ODP Hole 122-762B (Tables 1, 2)

Drilling on the Exmouth Plateau during Ocean Drilling Program Leg 122 recovered an almost complete Cenozoic sequence at Site 762. Sediments at this site contain abundant, diverse, and generally well-preserved calcareous nannofossils. The continuity of the stratigraphic sequence, preservation of the taxa, and availability of magnetostratigraphy offered an opportunity to construct a first-order biomagnetochronologic history for late Miocene-Quaternary calcareous nannofossils at Site 762. Magnetochronologically dated FADs/LADs for 23 different nannofossils are given in this study. FADs or LADs for five of these species (Discoaster blackstockae, D. calcaris, Rhabdosphaera claviger, R. longistylis, and R. procera) have never been presented before. In addition, a LAD for Ceratolithus rugosus is new. We believe these new age datums, and the complementary information on previous datums, will add to the growing refinement of Cenozoic biomagnetochronology.大洋钻探计划（Ocean Drilling Program）第122航次在埃克斯茅斯高原实施钻探期间，于762站位获取了近乎完整的新生代地层序列。该站位沉积物中富含多样且整体保存完好的钙质超微化石（calcareous nannofossils）。连续完整的地层序列、化石类群的保存状态，以及磁性地层学（magnetostratigraphy）数据的可获得性，为构建762站位晚中新世-第四纪钙质超微化石的一级生物磁性地层年代学框架提供了条件。本研究给出了23种超微化石的磁性地层定年首现事件（First Appearance Datums, FADs）与末现事件（Last Appearance Datums, LADs）。其中5个物种（Discoaster blackstockae、D. calcaris、Rhabdosphaera claviger、R. longistylis及R. procera）的首现/末现事件此前从未被正式报道。此外，Ceratolithus rugosus的末现事件为全新发现。我们认为，这些新的年代基准面及其对既往年代基准面的补充信息，将推动新生代生物磁性地层学研究的持续精细化。