Title: Sedimentary Controls on the Formation and Preservation of Microbial Mats in Siliciclastic Deposits: A Case Study from the Upper Neoproterozoic Nama Group, Namibia
Abstract: Other| December 01, 2002 Sedimentary Controls on the Formation and Preservation of Microbial Mats in Siliciclastic Deposits: A Case Study from the Upper Neoproterozoic Nama Group, Namibia NORA NOFFKE; NORA NOFFKE 1Department of Organismic and Evolutionary Biology, Harvard University, 26 Oxford Street, Cambridge, MA 02138 * Current address: Department of Ocean, Earth and Atmospheric Sciences, Old Dominion University, 4600 Elkhorn Avenue, Norfolk, VA 23529 Search for other works by this author on: GSW Google Scholar ANDREW H. KNOLL; ANDREW H. KNOLL 1Department of Organismic and Evolutionary Biology, Harvard University, 26 Oxford Street, Cambridge, MA 02138 Search for other works by this author on: GSW Google Scholar JOHN P. GROTZINGER JOHN P. GROTZINGER 2Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139 Search for other works by this author on: GSW Google Scholar Author and Article Information NORA NOFFKE * Current address: Department of Ocean, Earth and Atmospheric Sciences, Old Dominion University, 4600 Elkhorn Avenue, Norfolk, VA 23529 1Department of Organismic and Evolutionary Biology, Harvard University, 26 Oxford Street, Cambridge, MA 02138 ANDREW H. KNOLL 1Department of Organismic and Evolutionary Biology, Harvard University, 26 Oxford Street, Cambridge, MA 02138 JOHN P. GROTZINGER 2Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139 Publisher: SEPM Society for Sedimentary Geology Accepted: 19 Apr 2002 First Online: 03 Mar 2017 Online ISSN: 1938-5323 Print ISSN: 0883-1351 Society for Sedimentary Geology PALAIOS (2002) 17 (6): 533–544. https://doi.org/10.1669/0883-1351(2002)017<0533:SCOTFA>2.0.CO;2 Article history Accepted: 19 Apr 2002 First Online: 03 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation NORA NOFFKE, ANDREW H. KNOLL, JOHN P. GROTZINGER; Sedimentary Controls on the Formation and Preservation of Microbial Mats in Siliciclastic Deposits: A Case Study from the Upper Neoproterozoic Nama Group, Namibia. PALAIOS 2002;; 17 (6): 533–544. doi: https://doi.org/10.1669/0883-1351(2002)017<0533:SCOTFA>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 SocietyPALAIOS Search Advanced Search Abstract Shallow-marine, siliciclastic depositional systems are dominated by physical sedimentary processes, with penecontemporaneous cementation playing only a minor role in sediment dynamics. For this reason, microbial mats rarely form stromatolites in siliciclastic environments; instead, mats are preserved as wrinkle structures on bedding surfaces.Microbial mat signatures should be widespread in siliciclastic rocks deposited before the Cambrian Period; however, siliciclastic shelf successions of the upper Neoproterozoic Nudaus Formation, Nama Group, Namibia, contain only sparsely distributed wrinkle structures. The facies distribution of observed structures reflects the superposition of a taphonomic window of mat preservation on the ecological window of mat development. Mat colonization is favored by clean, fine-grained, translucent quartz sands deposited at sites where hydrodynamic flow is sufficient to sweep mud from mat surfaces but insufficient to erode biostabilized laminae. During periods of reduced water agitation, microbial baffling, trapping, and binding entrain quartz grains into mat fabrics, increasing the thickness of the living mat layer. Mat preservation is facilitated by subsequent sedimentary events that bury the microbial structures without causing erosional destruction. Pressure originating from sediment loading forms molds and casts at bedding planes, inducing the formation of wrinkle structures.In storm-influenced shelf successions of the Nudaus Formation, wrinkle structures are restricted to quartz-rich fine sandstone beds, 2–20 cm thick, that alternate with thin interlayers of sandy mud- or siltstones. Such a lithological facies developed only sporadically on the Nudaus shelf, but is common in shallow-marine siliciclastic rocks of older Neoproterozoic age exposed in the Naukluft Nappe Complex. The observed relationship between sedimentary environment and microbial mat preservation can be observed in other Proterozoic and Phanerozoic siliciclastic rocks, as well as in modern environments. This facies dependence provides a paleoenvironmental and taphonomic framework within which investigations of secular change in mat abundance must be rooted. Understanding the physical sedimentary parameters that control the formation and preservation of microbial structures in siliciclastic regimes can facilitate exploration for biological signatures in early sedimentary rocks on Earth or other planets. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.
Publication Year: 2002
Publication Date: 2002-12-01
Language: en
Type: article
Indexed In: ['crossref']
Access and Citation
Cited By Count: 187
AI Researcher Chatbot
Get quick answers to your questions about the article from our AI researcher chatbot