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首页> 外文学位 >High-Resolution Carbon Isotope Stratigraphy of the Ordovician-Silurian Boundary on Anticosti Island, Quebec: Regional and Global Implications.
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High-Resolution Carbon Isotope Stratigraphy of the Ordovician-Silurian Boundary on Anticosti Island, Quebec: Regional and Global Implications.

机译：魁北克安蒂科斯蒂岛上奥陶纪-西律纪边界的高分辨率碳同位素地层学：区域和全球意义。

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摘要

The end-Ordovician was a critical time in Earth history and marked the occurrence of a mass extinction and a period of continental glaciation. The Ellis Bay Formation on Anticosti Island in Quebec represents up to 100 meters of relatively undisturbed, continuous, low latitude, shallow water carbonate ramp deposits that span the Hirnantian Stage and terminate close to the Ordovician-Silurian (O-S) boundary. In this study, approximately 400 samples of micritic limestones were collected from six Ellis Bay sections ranging from the basin margin to more distal basin center of the Anticosti Basin. delta13C and delta18O isotopic ratios were measured from these samples and integrated within a recently proposed framework of sequence stratigraphy and biostratigraphy for the Ellis Bay Formation. The measured delta13C values in most sections show a positive excursion (∼2‰) in the lower Ellis Bay Formation followed by a larger excursion (∼4‰) in the upper Ellis Bay Formation. The delta 13C profile of the Ellis Bay Formation on Anticosti Island exhibits a pattern similar to those of other profiles in graptolite-rich Hirnantian basinal successions from the rest of the world. The delta13C record on Anticosti Island is not consistent with predictions and observations based on current models that describe the state and evolution of the global carbon cycle during the Late Ordovician.
机译：奥陶纪末期是地球历史上的关键时期，标志着大规模灭绝和大陆冰川期的发生。魁北克安蒂科斯蒂岛上的埃利斯湾地层代表了长达100米的相对不受干扰的，连续的，低纬度的浅水碳酸盐斜坡道沉积物，其跨越了赫南特阶段，并终止于奥陶纪-lur留纪（O-S）边界附近。在这项研究中，从Ellis湾的6个剖面中收集了大约400个微影石灰岩样品，从盆地边缘到Anticosti盆地的更远的盆地中心。从这些样品中测量了delta13C和delta18O同位素比率，并将其整合到Ellis Bay地层的层序地层学和生物地层学的最新提议框架中。在大多数剖面中测得的delta13C值在较低的埃利斯湾地层中显示正偏移（〜2‰），随后在较高的埃利斯湾地层中显示较大的偏移（〜4‰）。安提科斯蒂岛上埃利斯湾组的三角洲13C剖面与来自世界其他地方的富含滑石的赫南特盆地陆相演替中的其他剖面相似。 Anticosti岛上的delta13C记录与基于描述奥陶纪晚期全球碳循环的状态和演变的当前模型的预测和观察不一致。

著录项

  • 作者

    Wickson, Steven.;

  • 作者单位

    University of Ottawa (Canada).;

  • 授予单位 University of Ottawa (Canada).;
  • 学科 Geology.;Geochemistry.;Sedimentary Geology.
  • 学位 M.Sc.
  • 年度 2011
  • 页码 116 p.
  • 总页数 116
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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