• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Nature >Formation of the 'Great Unconformity' as a trigger for the Cambrian explosion
【24h】

Formation of the 'Great Unconformity' as a trigger for the Cambrian explosion

机译：形成“严重不整合”引发寒武纪爆炸

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

“大不整合面”是一个世界范围的地层特征，rn指大陆结晶基岩与较年轻的浅层海洋沉积物之rn间的一个分界线。偶尔，如在本期封面所示的rn在Toroweap Overlook这个地方所拍摄的“大峡rn谷”那样，它会暴露在地球表面上，产生戏剧rn化的效果。自从这个术语在1 869年被创造出rn来之后，地质学家便～直在就“大不整合面”rn的起源和全球影响进行辩论。现在，ShananrnPeters和Robell Gairles发表了对来自北美830rn个地点的地层和岩相数据以及岩石学和地球化rn学数据所做的一项新的分析。他们发现的证据rn表明，“大不整合面”的形成曾经引起大陆风rn化增强，同时也引起大范围的浅海中海洋碱性rn增强和离子强度增强，而这反过来又触发了生rn物矿化作用以及寒武纪海洋动物的爆发。%The transition between the Proterozoic and Phanerozoic eons, beginning 542 million years (Myr) ago, is distinguished by the diversification of multicellular animals and by their acquisition of mineralized skeletons during the Cambrian period1. Considerable progress has been made in documenting and more precisely correlating biotic patterns in the Neoproterozoic-Cambrian fossil record with geochemical and physical environmental perturbations~(2-5), but the mechanisms responsible for those perturbations remain uncertain~(1,2). Here we use new stratigraphic and geochemical data to show that early Palaeozoic marine sediments deposited approximately 540-480 Myr ago record both an expansion in the area of shallow epicontinental seas and anomalous patterns of chemical sedimentation that are indicative of increased oceanic alkalinity and enhanced chemical weathering of continental crust. These geochemical conditions were caused by a protracted period of widespread continental denudation during the Neoproterozoic followed by extensive physical reworking of soil, regolith and basement rock during the first continental-scale marine transgression of the Phanerozoic. The resultant globally occurring stratigraphic surface, which in most regions separates continental crystalline basement rock from much younger Cambrian shallow marine sedimentary deposits, is known as the Great Unconformity6. Although Darwin and others have interpreted this widespread hiatus in sedimentation on the continents as a failure of the geologic record, this palaeo-geomorphic surface represents a unique physical environmental boundary condition that affected seawater chemistry during a time of profound expansion of shallow marine habitats. Thus, the formation of the Great Unconformity may have been an environmental trigger for the evolution of biomineralization and the 'Cambrian explosion' of ecologic and taxonomic diversity following the Neoproterozoic emergence of animals.
机译：“大不整合面”是一个世界范围的地层特征，rn指大陆结晶基岩与较年轻的浅层海洋沉积物之rn间的一个分界线。偶尔，如在本期封面所示的rn在Toroweap Overlook这个地方所拍摄的“大峡rn谷”那样，它会暴露在地球表面上，产生戏剧rn化的效果。自从这个术语在1 869年被创造出rn来之后，地质学家便～直在就“大不整合面”rn的起源和全球影响进行辩论。现在，ShananrnPeters和Robell Gairles发表了对来自北美830rn个地点的地层和岩相数据以及岩石学和地球化rn学数据所做的一项新的分析。他们发现的证据rn表明，“大不整合面”的形成曾经引起大陆风rn化增强，同时也引起大范围的浅海中海洋碱性rn增强和离子强度增强，而这反过来又触发了生rn物矿化作用以及寒武纪海洋动物的爆发。%The transition between the Proterozoic and Phanerozoic eons, beginning 542 million years (Myr) ago, is distinguished by the diversification of multicellular animals and by their acquisition of mineralized skeletons during the Cambrian period1. Considerable progress has been made in documenting and more precisely correlating biotic patterns in the Neoproterozoic-Cambrian fossil record with geochemical and physical environmental perturbations~(2-5), but the mechanisms responsible for those perturbations remain uncertain~(1,2). Here we use new stratigraphic and geochemical data to show that early Palaeozoic marine sediments deposited approximately 540-480 Myr ago record both an expansion in the area of shallow epicontinental seas and anomalous patterns of chemical sedimentation that are indicative of increased oceanic alkalinity and enhanced chemical weathering of continental crust. These geochemical conditions were caused by a protracted period of widespread continental denudation during the Neoproterozoic followed by extensive physical reworking of soil, regolith and basement rock during the first continental-scale marine transgression of the Phanerozoic. The resultant globally occurring stratigraphic surface, which in most regions separates continental crystalline basement rock from much younger Cambrian shallow marine sedimentary deposits, is known as the Great Unconformity6. Although Darwin and others have interpreted this widespread hiatus in sedimentation on the continents as a failure of the geologic record, this palaeo-geomorphic surface represents a unique physical environmental boundary condition that affected seawater chemistry during a time of profound expansion of shallow marine habitats. Thus, the formation of the Great Unconformity may have been an environmental trigger for the evolution of biomineralization and the 'Cambrian explosion' of ecologic and taxonomic diversity following the Neoproterozoic emergence of animals.

著录项

  • 来源
    《Nature》 |2012年第7394期|p.363-366C3|共5页
  • 作者

    Shanan E. Peters; Robert R. Gaines;

  • 作者单位

    Department of Geoscience, University of Wisconsin, Madison, Wisconsin 53706, USA;

    Geology Department, Pomona College, Claremont, California 91711, USA;

  • 收录信息 美国《科学引文索引》(SCI);美国《工程索引》(EI);美国《生物学医学文摘》(MEDLINE);美国《化学文摘》(CA);
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号