Origin of 3.45 Ga coniform stromatolites in Warrawoona Group, Western Australia

Research Article| August 01, 1999 Origin of 3.45 Ga coniform stromatolites in Warrawoona Group, Western Australia H. J. Hofmann; H. J. Hofmann 1Department of Geology, University of Montreal, P.O. Box 6128, Station A, Montreal, Quebec H3C 3J7, Canada Search for other works by this author on: GSW Google Scholar K. Grey; K. Grey 2Geological Survey of Western Australia, 100 Plain Street, East Perth 6004, Western Australia, Australia Search for other works by this author on: GSW Google Scholar A. H. Hickman; A. H. Hickman 2Geological Survey of Western Australia, 100 Plain Street, East Perth 6004, Western Australia, Australia Search for other works by this author on: GSW Google Scholar R. I. Thorpe R. I. Thorpe 3Geological Survey of Canada, 601 Booth Street, Ottawa, Ontario K1A 0E8, Canada Search for other works by this author on: GSW Google Scholar GSA Bulletin (1999) 111 (8): 1256–1262. https://doi.org/10.1130/0016-7606(1999)111<1256:OOGCSI>2.3.CO;2 Article history first online: 01 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 H. J. Hofmann, K. Grey, A. H. Hickman, R. I. Thorpe; Origin of 3.45 Ga coniform stromatolites in Warrawoona Group, Western Australia. GSA Bulletin 1999;; 111 (8): 1256–1262. doi: https://doi.org/10.1130/0016-7606(1999)111<1256:OOGCSI>2.3.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 SocietyGSA Bulletin Search Advanced Search Abstract A new occurrence of conical and branched pseudocolumnar stromatolites in Archean dolostones in the Pilbara region, Australia, contributes significant new morphologic information on such structures. These remains are interpreted as probably representing, in part, microbially mediated accretionary growth surfaces in an Archean hypersaline depositional basin. The structures comprise laterally linked pseudocolumns of centimeter width and decimeter height, with first-order conical laminae of as much as 15 cm of synoptic relief and apical angles of 30°–80°. The conical laminae are modified by a second-order, centimeter-scale, low-amplitude primary corrugate lamination, with crests and troughs occasionally stacked to form satellitic, obliquely directed pseudocolumns; bedding surfaces exhibit a preferred direction of elongation of the cones, an orientation that is orthogonal (and unrelated) to the trend of younger folding; the microstructure is secondary. The stromatolites are better preserved than those previously known from chert in the Warrawoona succession. The remains exhibit certain distinct morphologic attributes corresponding to those in younger stromatolites, such as displayed by Thyssagetes and Jacutophyton, whose biogenicity is generally accepted (although difficult to demonstrate conclusively); the conical Warrawoona forms may represent the oldest known precursor of these taxa. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.