Microbeam U-Pb Zircon dating of the Makwassie Formation and underlying units in the Ventersdorp Supergroup of South Africa

Cornell, David H.; Meintjes, P.G.; Westhuizen, W.A. van der; Frei, Dirk

doi:10.25131/gssajg.120.4.525

Cited by 17 publications

(17 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The only indication that this dated series of coeval magmatic events may have been spatially more significant is an age of 2781 ± 5 Ma for a dacite in a drill core ∼480 km to the southwest, near Kimberley ( Fig. 1; Cornell et al, 2017). It has thus been speculated that the Klipriviersberg Group forms part of this ca.…”

Section: Regional Geologymentioning

confidence: 87%

“…Graben-fill is characterized by rapid facies changes and wedgeshaped geometries (de Kock et al, 2012), with possible caldera formation accounting for the excessively thick formations (Meintjes and van der Westhuizen, 2018a). The Makwassie Formation has been dated by Armstrong et al (1991) at 2709 ± 8 Ma and more recently by Cornell et al (2017) at 2720 ± 2 Ma at several localities (Table 1). Cornell et al (2017) further presented an age for the underlying Goedgenoeg Formation of 2746 ± 9 Ma (Table 1).…”

Section: Regional Geologymentioning

confidence: 99%

“…The Makwassie Formation has been dated by Armstrong et al (1991) at 2709 ± 8 Ma and more recently by Cornell et al (2017) at 2720 ± 2 Ma at several localities (Table 1). Cornell et al (2017) further presented an age for the underlying Goedgenoeg Formation of 2746 ± 9 Ma (Table 1). These ages by Cornell et al (2017) for the Platberg Group are in agreement with age constraints from many lithological correlatives of the Ventersdorp Supergroup that have been described under various names due to non-continuous outcrop in isolated grabens (Fig.…”

Section: Regional Geologymentioning

confidence: 99%

“…The Ventersdorp Supergroup overlies the worldclass gold-and uranium-bearing conglomerate reefs of the Witwatersrand Supergroup. However, the exact timing of the formation of the Ventersdorp Supergroup has been a matter of controversy, with implications for the termination of Witwatersrand Supergroup and gold deposition (Armstrong et al, 1991;Wingate, 1998;de Kock et al, 2012;Cornell et al, 2017). Armstrong et al (1991) reported 2714 ± 16 Ma and 2709 ± 8 Ma ages (Table 1) for the lower (Klipriviersberg Group) and middle (Makwassie Formation of the Platberg Group) part of the Ventersdorp Supergroup, respectively, making the whole volcanic province a single, but pulsed LIP, ∼10 m.y.…”

Section: Introductionmentioning

confidence: 99%

“…2.71 Ga (Wingate, 1998;de Kock et al, 2012;Cornell et al, 2017). For example, Cornell et al (2017) re-dated the quartz porphyry of the Makwassie Formation at 2720 ± 2 Ma (Table 1), calling into question the age of ca. 2709 Ma obtained by Armstrong et al (1991) for the same unit, as well as the ca.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Neoarchean large igneous provinces on the Kaapvaal Craton in southern Africa re-define the formation of the Ventersdorp Supergroup and its temporal equivalents

et al. 2020

View full text Add to dashboard Cite

U-Pb geochronology on baddeleyite is a powerful technique that can be applied effectively to chronostratigraphy. In southern Africa, the Kaapvaal Craton hosts a wellpreserved Mesoarchean to Paleoproterozoic geological record, including the Neoarchean Ventersdorp Supergroup. It overlies the Witwatersrand Supergroup and its world-class gold deposits. The Ventersdorp Supergroup comprises the Klipriviersberg Group, Platberg Group, and Pniel Group. However, the exact timing of formation of the Ventersdorp Supergroup is controversial. Here we present 2789 ± 4 Ma and 2787 ± 2 Ma U-Pb isotope dilution-thermal ionization mass spectrometry (ID-TIMS) baddeleyite ages and geochemistry on mafic sills intruding the Witwatersrand Supergroup, and we interpret these sills as feeders to the overlying Klipriviersberg Group flood basalts. This constrains the age of the Witwatersrand Supergroup and gold mineralization to at least ca. 2.79 Ga. We also report 2729 ± 5 Ma and 2724 ± 7 Ma U-Pb ID-TIMS baddeleyite ages and geochemistry from a mafic sill intruding the Pongola Supergroup and on an east-northeast-trending mafic dike, respectively. These new ages distinguish two of the Ventersdorp Supergroup magmatic events: the Klipriviersberg and Platberg. The Ventersdorp Supergroup can now be shown to initiate and terminate with two large ig-neous provinces (LIPs), the Klipriviersberg and Allanridge, which are separated by Platberg volcanism and sedimentation. The age of the Klipriviersberg LIP is 2791-2779 Ma, and Platberg volcanism occurred at 2754-2709 Ma. The Allanridge LIP occurred between 2709-2683 Ma. Klipriviersberg, Platberg, and Allanridge magmatism may be genetically related to mantle plume(s). Higher heat flow and crustal melting resulted as a mantle plume impinged below the Kaapvaal Craton lithosphere, and this was associated with rifting and the formation of LIPs.

show abstract

Section: Regional Geologymentioning

confidence: 87%