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首页> 外文学位 >Sedimentology and micropaleontology (benthic foraminifera) of the Cretaceous-Tertiary transition: Correlation between the Gulf of Mexico and the Tethys area (Spanish text).
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Sedimentology and micropaleontology (benthic foraminifera) of the Cretaceous-Tertiary transition: Correlation between the Gulf of Mexico and the Tethys area (Spanish text).

机译：白垩纪-第三纪过渡期的沉积学和微古生物学（底栖有孔虫）：墨西哥湾和特提斯地区之间的相关性（西班牙文本）。

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摘要

The sedimentological and micropaleontological study of several Cretaceous-Tertiary sections has contributed to a more detailed knowledge of this moment of the Earth's history, which is characterized by the extinction of numerous organisms and the sedimentation of anomalous deposits.; In the Gulf of Mexico area, the Cretaceous/Tertiary (K/T) boundary is located at the base of a Clastic Unit, variable in thickness and deposited under turbiditic currents. These currents have been related to the seismic instability triggered by a meteoritic impact occurred at Chicxulub (Yucatán) in coincidence with the K/T boundary. Impact evidences are less evident in the Tethys area, where the K/T boundary is located under a decimetric layer of dark clays that contain a red layer with geochemical and mineralogical anomalies toward its base. The study of benthic foraminifera allowed us to infer the paleobathymetry of all sections, as well as to document the allochtony of the Clastic Unit in the Gulf of Mexico.; Whereas benthic foraminifera suggest environmental stability during the Maastrichtian, important changes in the communities were recorded in coincidence with the K/T boundary, indicating a drastic drop in primary productivity. The benthic response has been related to the web-chain collapse, and to the progressive recovery of the productivity through the basal Danian.; Sedimentological and micropaleontological evidences are compatible with the theory of a meteoritic impact occurred at the K/T boundary, that led to an anomalous sedimentation and globally triggered paleoenvironmental and biological processes.
机译：对白垩纪-第三纪的部分进行了沉积学和微古生物学研究，使人们对地球历史这一时刻有了更详细的了解，其特征是许多生物的灭绝和异常沉积的沉积。在墨西哥湾地区，白垩纪/第三纪（K / T）边界位于碎屑单元的底部，其厚度可变，并在湍流作用下沉积。这些电流与奇克苏鲁布（尤卡坦州）发生的与K / T边界重合的陨石撞击引起的地震不稳定有关。在特提斯地区，碰撞证据不太明显，该地区的K / T边界位于深层粘土的十分之一厚层以下，该深层粘土的红色层底部具有地球化学和矿物学异常。对底栖有孔虫的研究使我们能够推断出所有断面的古生物学，并记录了墨西哥湾碎屑岩单元的异位作用。底栖有孔虫提示马斯特里赫特时期的环境稳定，但与K / T边界一致记录了群落的重要变化，表明初级生产力急剧下降。底栖反应与网链塌陷有关，与通过基底大年纪逐渐提高生产力有关。沉积学和微古生物学的证据与在K / T边界发生的陨石影响的理论是相容的，这导致了异常沉积，并在全球范围内触发了古环境和生物过程。

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  • 作者

    Alegret Badiola, Laia.;

  • 作者单位

    Universidad de Zaragoza (Spain).;

  • 授予单位 Universidad de Zaragoza (Spain).;
  • 学科 Geology.; Paleontology.; Paleoecology.
  • 学位 Dr.
  • 年度 2002
  • 页码 478 p.
  • 总页数 478
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 地质学;古生物学;古生物学;
  • 关键词

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