1.6 Ga U-Pb zircon age for the Chorhat Sandstone, lower Vindhyan, India: Possible implications for early evolution of animals

Abstract

Research Article| February 01, 2002 1.6 Ga U-Pb zircon age for the Chorhat Sandstone, lower Vindhyan, India: Possible implications for early evolution of animals Birger Rasmussen; Birger Rasmussen 1Department of Geology and Geophysics, University of Western Australia, Crawley 6009, Australia Search for other works by this author on: GSW Google Scholar Pradip K. Bose; Pradip K. Bose 2Department of Geological Sciences, Jadavpur University, Calcutta 700 032, India Search for other works by this author on: GSW Google Scholar Subir Sarkar; Subir Sarkar 2Department of Geological Sciences, Jadavpur University, Calcutta 700 032, India Search for other works by this author on: GSW Google Scholar Santanu Banerjee; Santanu Banerjee 3Department of Earth Sciences, Indian Institute of Technology, Bombay, Powai, Mumbai 400 076, India Search for other works by this author on: GSW Google Scholar Ian R. Fletcher; Ian R. Fletcher 4Centre for Global Metallogeny, Department of Geology and Geophysics, University of Western Australia, Crawley 6009, Australia Search for other works by this author on: GSW Google Scholar Neal J. McNaughton Neal J. McNaughton 4Centre for Global Metallogeny, Department of Geology and Geophysics, University of Western Australia, Crawley 6009, Australia Search for other works by this author on: GSW Google Scholar Author and Article Information Birger Rasmussen 1Department of Geology and Geophysics, University of Western Australia, Crawley 6009, Australia Pradip K. Bose 2Department of Geological Sciences, Jadavpur University, Calcutta 700 032, India Subir Sarkar 2Department of Geological Sciences, Jadavpur University, Calcutta 700 032, India Santanu Banerjee 3Department of Earth Sciences, Indian Institute of Technology, Bombay, Powai, Mumbai 400 076, India Ian R. Fletcher 4Centre for Global Metallogeny, Department of Geology and Geophysics, University of Western Australia, Crawley 6009, Australia Neal J. McNaughton 4Centre for Global Metallogeny, Department of Geology and Geophysics, University of Western Australia, Crawley 6009, Australia Publisher: Geological Society of America Received: 17 May 2001 Revision Received: 26 Sep 2001 Accepted: 17 Oct 2001 First Online: 02 Jun 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (2002) 30 (2): 103–106. https://doi.org/10.1130/0091-7613(2002)030<0103:GUPZAF>2.0.CO;2 Article history Received: 17 May 2001 Revision Received: 26 Sep 2001 Accepted: 17 Oct 2001 First Online: 02 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Birger Rasmussen, Pradip K. Bose, Subir Sarkar, Santanu Banerjee, Ian R. Fletcher, Neal J. McNaughton; 1.6 Ga U-Pb zircon age for the Chorhat Sandstone, lower Vindhyan, India: Possible implications for early evolution of animals. Geology 2002;; 30 (2): 103–106. doi: https://doi.org/10.1130/0091-7613(2002)030<0103:GUPZAF>2.0.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract Bedding-plane markings in the Chorhat Sandstone (lower Vindhyan), central India, were recently interpreted as burrows produced by triploblastic animals. Because the rocks were thought to be older than 1000 Ma, these structures were regarded as the oldest fossil evidence for metazoan life. However, the biological origin of the markings has been questioned, as has their age. Current age estimates are based on K-Ar, Rb-Sr, and fission- track dates, though some contentious evidence suggests that the rocks may be only 540 Ma. Here we provide the first robust age data for the lower Vindhyan by using SHRIMP (sensitive, high-resolution ion microprobe) U-Pb zircon geochronology to date silicified tuffs bounding the Chorhat Sandstone. Our results show that the sediments were deposited between 1628 ± 8 Ma and 1599 ± 8 Ma. If the Chorhat markings are burrows left by worm-like animals, then our data suggest that complex metazoans had evolved before 1600 Ma, 1 b.y. before the "Cambrian explosion" when animals rapidly diversified and became ecologically dominant. However, given the doubts expressed about the origin of the bedding-plane structures, as well as the surprisingly "old" age of the host rocks, further studies are urgently required to provide supportive evidence. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.