• 主题
高级搜索  >
历史搜索 清空历史
首页> 美国卫生研究院文献>Proceedings of the National Academy of Sciences of the United States of America >The controversial Cambrian fossils of the Vindhyan are real but more than a billion years older
【2h】

The controversial Cambrian fossils of the Vindhyan are real but more than a billion years older

机译：Vindhyan有争议的寒武纪化石是真实的但已有十亿多年的历史了

代理获取
本网站仅为用户提供外文OA文献查询和代理获取服务，本网站没有原文。下单后我们将采用程序或人工为您竭诚获取高质量的原文，但由于OA文献来源多样且变更频繁，仍可能出现获取不到、文献不完整或与标题不符等情况，如果获取不到我们将提供退款服务。请知悉。
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

The age of the Vindhyan sedimentary basin in central India is controversial, because geochronology indicating early Proterozoic ages clashes with reports of Cambrian fossils. We present here an integrated paleontologic–geochronologic investigation to resolve this conundrum. New sampling of Lower Vindhyan phosphoritic stromatolitic dolomites from the northern flank of the Vindhyans confirms the presence of fossils most closely resembling those found elsewhere in Cambrian deposits: annulated tubes, embryo-like globules with polygonal surface pattern, and filamentous and coccoidal microbial fabrics similar to Girvanella and Renalcis. None of the fossils, however, can be ascribed to uniquely Cambrian or Ediacaran taxa. Indeed, the embryo-like globules are not interpreted as fossils at all but as former gas bubbles trapped in mucus-rich cyanobacterial mats. Direct dating of the same fossiliferous phosphorite yielded a Pb–Pb isochron of 1,650 ± 89 (2σ) million years ago, confirming the Paleoproterozoic age of the fossils. New U–Pb geochronology of zircons from tuffaceous mudrocks in the Lower Vindhyan Porcellanite Formation on the southern flank of the Vindhyans give comparable ages. The Vindhyan phosphorites provide a window of 3-dimensionally preserved Paleoproterozoic fossils resembling filamentous and coccoidal cyanobacteria and filamentous eukaryotic algae, as well as problematic forms. Like Neoproterozoic phosphorites a billion years later, the Vindhyan deposits offer important new insights into the nature and diversity of life, and in particular, the early evolution of multicellular eukaryotes.
机译：印度中部Vindhyan沉积盆地的年龄是有争议的，因为年代学表明元古生代时代早已与寒武纪化石的报道相冲突。我们在这里提出了一个完整的古生物学-地史学调查来解决这个难题。从Vindhyans北部的下Vindhyan磷化层状白云岩新取样，证实了与化石在寒武纪沉积物中最相似的化石的存在：环形管，具有多边形表面图案的胚状小球以及类似的丝状和球状微生物织物Girvanella和Renalcis。但是，这些化石都不能归因于独特的寒武纪或埃迪卡拉纪分类群。确实，类胚球根本不被解释为化石，而是被困在富含粘液的蓝细菌垫中的前气泡。对同一化石质亚磷酸盐的直接测年产生了1,650±89（2σ）的Pb-Pb等时线，证实了这些化石的古元古代。在Vindhyans南部翼缘下Vindhyan Porcellanite组中的凝灰质泥岩中的锆石的新U–Pb年代学给出了可比的年龄。 Vindhyan磷矿提供了3维保存的古元古代化石的窗口，这些化石类似于丝状和球状蓝藻细菌以及丝状真核藻类以及有问题的形式。像十亿年后的新元古代磷矿一样，Vindhyan矿床为生命的性质和多样性，尤其是多细胞真核生物的早期进化提供了重要的新见识。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
代理获取

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