Fields of study

I am interested in the geology of the Archaean Eon. Having worked as a researcher and lecturer at the universities of Zimbabwe, Witwatersrand, and KwaZulu-Natal, I am currently Professor at the University of Johannesburg. My main interest and expertise are centred on the Archaean geological record of southern Africa. I enjoy field work, which I combine with petrological and geochemical analyses to decipher the geological history of Archaean volcano-sedimentary successions. Improved analytical methods in the last few decades have led to new perspectives to better understand palaeo-environmental conditions favourable for microbial life. South Africa has an exceptional geological record of Archaean stromatolites, as the several kilometre-thick Malmani and Campellrand subgroups of the Transvaal Supergroup consist of little else, having been a prime microbial factory for carbonate precipitation, carbon sequestration and atmospheric oxygenation near the Archaean-Proterozoic boundary. Going farther back in time, stromatolitic carbonates become increasingly rare, with some minor occurrences situated in the 2.7 Ga Ventersdorp Supergroup and the 2.95 Ga Pongola Supergroup. Prior to 3.0 Ga, the record of open-marine carbonate sediments becomes virtually non-existent. Despite the absence of biologically mediated carbonate precipitation, microbial life was abundant in the Palaeoarchaean, as exemplified by silicified microbial mats in photic zone environments. And as preserved at two sites in South Africa, microbes built some of the oldest stromatolites known on Earth. This project is aimed to shed light on the origin of the oldest macro-scale biochemical precipitates present in South Africa.