NEW EVIDENCE FOR THE AGE AND PALAEOECOLOGY OF THE KNYSNA FORMATION, SOUTH AFRICA

Abstract

Research Article| September 01, 2010 NEW EVIDENCE FOR THE AGE AND PALAEOECOLOGY OF THE KNYSNA FORMATION, SOUTH AFRICA A.S. CARR; A.S. CARR Department of Geography, University of Leicester, United Kingdom, e-mail: asc18@le.ac.uk; ab269@le.ac.uk Search for other works by this author on: GSW Google Scholar A. BOOM; A. BOOM Department of Geography, University of Leicester, United Kingdom, e-mail: asc18@le.ac.uk; ab269@le.ac.uk Search for other works by this author on: GSW Google Scholar A. DUNAJKO; A. DUNAJKO Sheffield Centre for International Drylands Research, Department of Geography, University of Sheffield, United Kingdom, e-mail: ggp07acd@shef.ac.uk; m.d.bateman@shef.ac.uk Search for other works by this author on: GSW Google Scholar M.D. BATEMAN; M.D. BATEMAN Sheffield Centre for International Drylands Research, Department of Geography, University of Sheffield, United Kingdom, e-mail: ggp07acd@shef.ac.uk; m.d.bateman@shef.ac.uk Search for other works by this author on: GSW Google Scholar P.J. HOLMES; P.J. HOLMES Department of Geography, University of the Free State, South Africa, e-mail: holmespj@ufs.ac.za Search for other works by this author on: GSW Google Scholar J.-C. BERRIO J.-C. BERRIO Department of Geography, University of Leicester, United Kingdom, e-mail: jcb34@le.ac.uk Search for other works by this author on: GSW Google Scholar Author and Article Information A.S. CARR Department of Geography, University of Leicester, United Kingdom, e-mail: asc18@le.ac.uk; ab269@le.ac.uk A. BOOM Department of Geography, University of Leicester, United Kingdom, e-mail: asc18@le.ac.uk; ab269@le.ac.uk A. DUNAJKO Sheffield Centre for International Drylands Research, Department of Geography, University of Sheffield, United Kingdom, e-mail: ggp07acd@shef.ac.uk; m.d.bateman@shef.ac.uk M.D. BATEMAN Sheffield Centre for International Drylands Research, Department of Geography, University of Sheffield, United Kingdom, e-mail: ggp07acd@shef.ac.uk; m.d.bateman@shef.ac.uk P.J. HOLMES Department of Geography, University of the Free State, South Africa, e-mail: holmespj@ufs.ac.za J.-C. BERRIO Department of Geography, University of Leicester, United Kingdom, e-mail: jcb34@le.ac.uk Publisher: Geological Society of South Africa First Online: 09 Mar 2017 Online ISSN: 1996-8590 Print ISSN: 1012-0750 © 2010 Geological Society of South Africa South African Journal of Geology (2010) 113 (3): 241–256. https://doi.org/10.2113/gssajg.113.3.241 Article history First Online: 09 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation A.S. CARR, A. BOOM, A. DUNAJKO, M.D. BATEMAN, P.J. HOLMES, J.-C. BERRIO; NEW EVIDENCE FOR THE AGE AND PALAEOECOLOGY OF THE KNYSNA FORMATION, SOUTH AFRICA. South African Journal of Geology 2010;; 113 (3): 241–256. doi: https://doi.org/10.2113/gssajg.113.3.241 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 SocietySouth African Journal of Geology Search Advanced Search Abstract The existence of lignitic deposits (Knysna Formation) on the South African south coast, near to the town of Knysna has been recognised for more than a century. However, a combination of limited study and few natural exposures has meant that the age and stratigraphic position of the Knysna Formation are unclear, despite its potential as a palaeoenvironmental archive. We present a new suite of chronological, geochemical and palynological data obtained from a recently identified lignite exposure in this area. The lignite pollen assemblage is dominated by palms (Arecaceae), which are now locally extinct, and contains additional palynomorphs of tropical affinity, along with (moist-temperate) Podocarpus-type pollen, grasses, and herbaceous pollen types (e.g. Cliffortia-type, Asteraceae). Overall, the assemblage shows some commonalities with the Miocene Elandsfontein Formation in the Western Cape. The lignites are dominated by a diverse range of higher plant biomarkers, including abundant leaf wax lipids, as well as lignin monomers and leaf cuticle-derived macromolecular organic matter. All strongly indicate a terrestrial depositional setting, perhaps akin to contemporary palm swamps. A number of sesquiterpenoids imply the presence of gymnosperms, supporting observations from the pollen data and previously reported macro-fossil finds.The application of isothermal thermoluminescence techniques to coversands overlying the lignite produced a minimum age of ~1.7 Ma. Additional clues as to the likely age of the lignite are provided by compound-specific stable carbon isotope analyses of the leaf wax lipids. These are approximately 8‰ enriched relative to typical C3 vegetation leaf waxes, and imply a potential contribution from C4 vegetation. From this, an age post-dating the Oligocene may be inferred, and in conjunction with the site’s geomorphic setting, an age post dating the middle Miocene is considered plausible. This is markedly younger than previous (Eocene) age estimates for the Knynsa Formation. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.