Neogene calcareous nannofossils from ODP Leg 133 Great Barrier Reef@en

Calcareous nannofossils are generally abundant at the Queensland Trough transect sites (811 and 819 through 825) of Leg 133, and they provide the primary means of dating the Neogene sediments. Sites 819 through 821 to the east of the Great Barrier Reef yielded abundant, moderately preserved Pleistocene nannofossils. The sections are biostratigraphically complete, except for a very condensed interval or a hiatus in the middle Pleistocene section at Site 819. A similar hiatus has been identified at Site 822, where abundant, well-preserved upper Pliocene through Holocene nannofossils were recovered. Abundant and well-preserved nannofossils at Site 823 provide a fairly high-resolution biostratigraphy for the upper Miocene-Holocene sediments recovered, which is remarkable for this turbidite-ridden sequence. Calcareous nannofossils diminish as preservation deteriorates abruptly downhole at Sites 811, 824, and 825 on the Queensland Plateau, and the nannofossil biostratigraphy for the Pliocene and Miocene intervals is only marginally useful. […]钙质超微化石（Calcareous nannofossils）在第133航次昆士兰海槽剖面的站位（811、819至825）中通常十分富集，为新近纪沉积物的定年提供了主要手段。大堡礁以东的819至821站位产出了富集且保存程度中等的更新世超微化石。除819站位中更新统存在一段极薄的凝缩段或沉积间断外，其余剖面的生物地层序列均完整。822站位也存在类似的沉积间断，该站位采获了富集且保存完好的上新统上部至全新统超微化石。823站位产有丰富且保存完好的超微化石，可为所采获的上中新统-全新统沉积物提供较高分辨率的生物地层框架，这对于这套受浊积岩干扰的沉积序列而言尤为难得。在昆士兰高原的811、824及825站位，钙质超微化石的丰度随井下保存质量骤然下降而减少，其针对上新统与中新统地层的生物地层学分析仅具备有限的实用价值。[…]