Depositional setting and cyclic development of the lower part of the Witteberg Group (Mid- to Upper Devonian), Cape Supergroup, Western Cape, South Africa

Research Article| March 01, 2000 Depositional setting and cyclic development of the lower part of the Witteberg Group (Mid- to Upper Devonian), Cape Supergroup, Western Cape, South Africa E. Cotter E. Cotter Department of Geology, Bucknell University, Lewisburg, Pennsylvania 17837, U.S.A., E-mail: cotter@bucknell.edu Search for other works by this author on: GSW Google Scholar Author and Article Information E. Cotter Department of Geology, Bucknell University, Lewisburg, Pennsylvania 17837, U.S.A., E-mail: cotter@bucknell.edu Publisher: Geological Society of South Africa Accepted: 15 Dec 1999 First Online: 07 Mar 2017 Online ISSN: 1996-8590 Print ISSN: 1012-0750 © 2000 Geological Society of South Africa South African Journal of Geology (2000) 103 (1): 1–14. https://doi.org/10.2113/103.1.1 Article history Accepted: 15 Dec 1999 First Online: 07 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 E. Cotter; Depositional setting and cyclic development of the lower part of the Witteberg Group (Mid- to Upper Devonian), Cape Supergroup, Western Cape, South Africa. South African Journal of Geology 2000;; 103 (1): 1–14. doi: https://doi.org/10.2113/103.1.1 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 Mid- to Upper Devonian strata of the lower Witteberg Group in the Cape Fold Belt of South Africa comprise three principal facies deposited in the shoreface and contiguous inner shelfalong a storm-dominated coastal zone. Weakly burrowed mudrock with variable minor proportions of wave-rippled sandstone (linsen, flasers, hummocky cross stratification [HCSJ) (facies 1) accumulated in the inner shelf below, near, and just above storm wave base. Very fine- and fine-grained sandstone that displays flat and wavy lamination and HCS, as well as compound wave-ripple lamination (facies 2), was deposited in the lower shoreface above fair-weather wave base. Fine- to coarse-grained sandstone containing cross-lamination, anisotropic HCS, and compound wave-ripple lamination (facies 3) formed in the mid to upper shoreface. Regionally, lower Witteberg strata change from proportionally more facies 2 and 3 at proximal (northern) sites to mostly facies 1 at distal (southern) sites. The lower Witteberg Group consists of approximately 40 shallowing-upward facies sequences (parasequences) whose average thickness is approximately 12 m. These are grouped into progradational parasequence sets of up to 10 parasequences each for a total of approximately 3.5 parasequence sets in the lower Witteberg. The lowest parasequence set extends from the base of the Karoopoort Formation (top of underlying Bokkeveld Group) and culminates at the top of the Blinkberg Formation in the Witteberg Group, and approximately 2.5 parasequence sets make up the overlying Swartruggens Formation. The characteristics and stratigraphic architecture of the lower Witteberg Group are consequences of the interaction oftwo different orders of global sea-level fluctuation. The lower Witteberg parasequences had a periodicity between 250 and 300 ka, within the Milankovitch range, and their character and mean thickness are very similar to cyclic patterns recorded in contemporaneous Givetian—Frasnian siliciclastic and carbonate strata on four other continents. The progradational parasequence sets had a mean recurrence interval in the order of 3.0 Ma and can be correlated with specific third-order fluctuations of global sea-level proposed for contemporaneous Upper Devonian strata in Euramerica. This reinforces assignment of the age of the lower Witteberg as extending from the mid-Givetian Stage to the end of the Frasnian Stage. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.