Radiolarians of the Celebes Sea@en

Two sites were drilled in the Celebes Sea as part of Ocean Drilling Program Leg 124; Site 767 and Site 770. Radiolarians are preserved in Paleogene pelagic claystones with minor occurrences in certain Neogene successions. The brown clays that immediately overlie basalt at both sites contain radiolarians of the late middle Eocene Podocyrtis chalara Zone. Late Eocene radiolarians are not found, due to dissolution and probable hiatus. The Oligocene is represented by the Theocyrtis tuberosa and Dorcadospyris ateuchus Zones. Oligocene sediments are strongly dominated by abundant and diverse radiolarians of the TristylospyrislDorcadospyris lineage. Preservation of Paleogene radiolarian assemblages ranges from good to very poor. Late Miocene radiolarians of the Didymocyrtis antepenultima Zone are found only in Site 770. Other Neogene sediments are barren of radiolarian remains, with the exception of latest Pleistocene and Holocene sediments.作为大洋钻探计划（Ocean Drilling Program, ODP）第124航次的研究内容，科研人员在西里伯斯海钻取了767站位与770站位两处岩芯。放射虫（Radiolaria）化石赋存于古近纪远洋黏土岩中，在部分新近纪沉积序列中亦有少量产出。两个站位中直接覆于玄武岩之上的褐色黏土层，均产出了中始新世晚期Podocyrtis chalara生物带（Podocyrtis chalara Zone）的放射虫化石。受溶解作用与可能存在的沉积间断影响，未发现晚始新世的放射虫化石。渐新世地层以Theocyrtis tuberosa生物带（Theocyrtis tuberosa Zone）与Dorcadospyris ateuchus生物带（Dorcadospyris ateuchus Zone）为识别标志。渐新世沉积物中，以Tristylospyris与Dorcadospyris支系下丰富多样的放射虫化石占据绝对主导地位。古近纪放射虫组合的保存状态从良好至极差不等。仅在770站位中发现了晚中新世Didymocyrtis antepenultima生物带（Didymocyrtis antepenultima Zone）的放射虫化石。其余新近纪沉积物均未发现放射虫化石，仅晚更新世末期与全新世沉积物为例外。