Recalibration of the Tethyan shallow-benthic zonation across the Paleocene-Eocene boundary: the Egyptian record
Recalibration of the Tethyan shallow-benthic zonation across the Paleocene-Eocene boundary: the Egyptian record
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DOI：
10.1344/105.000000267
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发表时间：
2009-03
期刊：
影响因子：
1.5
通讯作者：
C. Scheibner;R. Speijer
中科院分区：
文献类型：
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作者：
C. Scheibner;R. Speijer
埃及的加拉拉山脉提供了优良的台盆横断面，其沉积物跨越了古新世/始新世 (P/E) 边界。这些相互交错的沉积物使得平台和开放海洋生物地层方案之间能够重新校准。我们调查了 18 个剖面，从以较大的底栖有孔虫为主的浅水碳酸盐台地边缘到有中上层和深海生物群的盆地泥灰岩。加拉拉样带详细记录了古新世晚期到始新世早期大型有孔虫的发育，特别是被称为大型有孔虫更替（LFT）的特提斯进化事件。这种更替将浅底栖区 4 (SBZ4) 典型的以球囊动物、混合动物和雷尼科索动物为主的古新世组合与以肺泡动物、nummulitids 和轨道动物为主的 SBZ5 组合区分开来。我们的数据与之前的研究一致，即较大的有孔虫周转（LFT）与古新世/始新世边界一致，由碳同位素偏移（CIE）划定，并且它与钙质超微化石亚区 NP9a/b 之间的边界、较小底栖有孔虫的底栖灭绝事件以及浮游有孔虫生物区之间的边界相关P5/E1。
The Galala Mountains in Egypt provide an excellent platform-basin transect with deposits spanning the Paleocene/ Eocene (P/E) boundary. These interfingering deposits enable a recalibration between platform and open marine biostratigraphic schemes. We investigated 18 sections from a shallow-water carbonate platform margin, dominated by larger benthic foraminifera, to basinal marls with pelagic and deep marine biota. The Late Paleocene to Early Eocene development of larger foraminifera is well recorded in the Galala transect, in particular the Tethyan evolutionary event known as the larger foraminifera turnover (LFT). This turnover distinguishes Paleocene assemblages dominated by glomalveolinids, miscellanids and ranikothalids typical for shallow benthic Zone 4 (SBZ4) from those of SBZ5, dominated by alveolinids, nummulitids, and orbitolitids. Our data agree with previous studies that suggested that the larger foraminifera turnover (LFT) coincides with the Paleocene/ Eocene boundary, delineated by the carbon isotopic excursion (CIE) and that it correlates with the boundary between calcareous nannofossils subzones NP9a/b, the benthic extinction event in smaller benthic foraminifera and the boundary between planktic foraminifera Biozones P5/E1.