Pleistocene calcareous nannofossil biochronology at IODP Site U1385 (Expedition 339)
Pleistocene calcareous nannofossil biochronology at IODP Site U1385 (Expedition 339)
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DOI：
10.1016/j.gloplacha.2015.10.004
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发表时间：
2015-12
影响因子：
3.9
通讯作者：
B. Balestra;J. Flores;D. Hodell;F. Hernández‐Molina;D. Stow
中科院分区：
文献类型：
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作者：
B. Balestra;J. Flores;D. Hodell;F. Hernández‐Molina;D. Stow
综合海洋钻探计划（IODP）第339次考察期间，在葡萄牙边缘的下斜坡上钻探了U1385站点（37°34′n, 10°7′w，海平面以下2578 m），以提供更新世千年尺度气候变化的海洋参考剖面。使用先进活塞盖（APC）取心5个孔，深度约为海底以下151 m (mbsf)，恢复了过去1.4 Ma的连续地层记录。本文介绍了标准和非常规钙质纳米化石生物地层事件的演替结果。钙质纳米化石的定量研究表明，整个岩心中保存完好，组合丰富。利用与U1385遗址新氧同位素地层记录的对比，对大多数常规更新世生物事件进行了识别，并校准了生物事件的时间。分析结果进一步揭示了huxleyi（bbbb4 μm）、Gephyrocapsa caribbeanica、Helicosphaera inversa、Gephyrocapsa omegaand ticulofenestra asanoi（bbbb6 μm）等圆形-亚圆形小型网状fenestrids的地层分布特征，为其地层格局的环境控制提供了新的认识。最后，对同一样品的纳米化石基准和氧同位素地层学进行比较，对事件的时间进行了准确的修正，提供了有价值的生物年代学信息。
During Integrated Ocean Drilling Program (IODP) Expedition 339, Site U1385 (37°34′N, 10°7′W, 2578 m below sea level) was drilled in the lower slope of the Portuguese margin, to provide a marine reference section of Pleistocene millennial-scale climate variability. Five holes were cored using the Advanced Piston Corer (APC) to a depth of ~ 151 m below sea floor (mbsf) recovering a continuous stratigraphic record covering the past 1.4 Ma. Here we present results of the succession of standard and unconventional calcareous nannofossil biostratigraphic events. The quantitative study of calcareous nannofossils showed well-preserved and abundant assemblages throughout the core. Most conventional Pleistocene events were recognized and the timing of bioevents were calibrated using correlation to the new oxygen isotope stratigraphy record developed for the Site U1385. The analyses provide further data on the stratigraphic distribution of selected species and genera, such as the largeEmiliania huxleyi(> 4 μm),Gephyrocapsa caribbeanica,Helicosphaera inversa,Gephyrocapsa omegaandReticulofenestra asanoi(> 6 μm) and other circular–subcircular small reticulofenestrids, resulting in new insights into the environmental control of their stratigraphic patterns. Finally, the comparison between nannofossil datums and oxygen isotope stratigraphy on the same samples has resulted in an accurate revision of timing of the events, providing valuable biochronologic information.