Meso-Archaean and Palaeo-Proterozoic sedimentary sequence stratigraphy of the Kaapvaal Craton

Abstract

ABSTRACT:The Kaapvaal Craton hosts a number of Precambrian sedimentary successions which were deposited between 3105 Ma (Dominion Group) and 1700 Ma (Waterberg Group) Although younger Precambrian sedimentary sequences outcrop within southern Africa, they are restricted either to the margins of the Kaapvaal craton, or are underlain by orogenic belts off the edge of the craton. The basins considered in this work are those which host the Witwatersrand and Pongola, Ventersdorp, Transvaal and Waterberg strata. Many of these basins can be considered to have formed as a response to reactivation along lineaments, which had initially formed by accretion processes during the amalgamation of the craton during the Mid-Archaean.Faulting along these lineaments controlled sedimentation either directly by controlling the basin margins, or indirectly by controlling the sediment source areas.Other basins are likely to be more controlled by thermal affects associated with mantle plumes. Accommodation in all these basins may have been generated primarily by flexural tectonics, in the case of the Witwatersrand, or by a combination of extensional and thermal subsidence in the case of the Ventersdorp, Transvaal and Waterberg. Wheeler diagrams are constructed to demonstrate stratigraphic relationships within these basins at the first-and second-order levels of cyclicity, andcan be used to demonstrate the development of accommodation space on the craton through the Precambrian.

Chapter 2 Classification of basins, with special reference to Proterozoic examples

“…Intrusion of the c. 2.5 Ga Bushveld Complex in central-north Kaapvaal terminated Transvaal deposition and was succeeded by complex rifted basins around the intrusion, accommodating continental deposits of the Waterberg (Fig. 2.8a) and Soutpansberg Groups (c. 2.05-1.7 Ga) (Bumby et al 2012 and references therein), with increasing uniqueness in each sub-basin.…”

A review of the inferred geodynamic evolution of the Dharwar craton over the ca. 3.5–2.5 Ga period, and possible implications for global tectonics

“…3.5-2.5 Ga, and will attempt to interpret commonalities and distinctions arising with Kaapvaal geodynamic history as a subordinate aim. The geo-dynamic evolution of Kaapvaal has been summarized in a number of recent papers (e.g., Eriksson et al 2006aEriksson et al , 2006bEriksson et al , 2011aBumby et al 2012;Mazumder et al 2012;Eriksson and Condie 2013) and is thus not repeated here except for a summary figure (Fig. 2).…”

“…For Kaapvaal, sequential accretion of complex small terranes of arc lithologies and TTG (tonalite-trondhjemitegranodiorite) appears to have dominated, and ages thus vary across Kaapvaal with ongoing accretion (e.g., de Wit et al 1992;Eglington and Armstrong 2004;Zeh et al 2009;Bumby et al 2012 and references therein). There is thus no common-age TTGgreenstone basement (cf.…”

“…Comparing the Dharwar Supergroup with evolution of the Kaapvaal craton (e.g., Bumby et al 2012, for a recent relevant review of Precambrian supracrustals, and references therein), succession 1 can possibly be considered as an approximate Witwatersrand Supergroup (Fig. 2) age equivalent, but in contrast to the latter's predominant shallow-marine to fluvial clastic sedimentary rocks, the Bababudan Group is a mainly volcanic succession.…”

“…2.7 Ga Ventersdorp Supergroup (volcanics and lesser immature clastic sedimentary deposits) and the lower part of the Transvaal Supergroup (cf. Chuniespoort-Ghaap groups, of dolomite and BIF; Bumby et al 2012) from Kaapvaal (Fig. 2).…”