Barberton Greenstone Belt

It is known for its gold mineralisation and for its komatiites, an unusual type of ultramafic volcanic rock named after the Komati River that flows through the belt.

The Barberton Greenstone Belt consists of a sequence of mafic to ultramafic lavas and metasedimentary rocks emplaced and deposited between 3.5 and 3.2 Ga.

Early stages of shield development are exposed in the Barberton Mountains where the continent formation first took place by magmatic accretion and tectonic amalgamation of small protocontinental blocks.

This crustal development phase was followed by a period of Mesoarchaean cratonic magmatism (3.1–3.0 Ga) and is marked by the formation of a large crescent-shaped, juvenile arc that was accreted onto the northern and western margins of the evolving Kaapvaal shield.

According to a study done by Westraat et al. (2005): "Multiple intrusive relationships and geochronological evidence suggests that granite sheeting and the assembly of the pluton occurred over a period of 3–13 million years.

According to a dissertation by Louzada (2003): "The upper part of the Hooggenoeg Formation[9] is characterized by ultramafic massive and pillow lavas, a trondhjemitic suite of silicified felsic intrusive and flow banded rocks, and sedimentary chert beds.

The intrusive group is related to the tonalite-trondhjemite-granodiorite TTG-suite Stolzburg Pluton, which intruded along the southern margin of the Barberton Greenstone Belt.

Similarities in geological setting, petrography, and geochemical (trace elements in particular) characteristics suggest a possible genetic relation between the two formations and support the theory that a combined continent Vaalbara existed ~3.45 Ga.

In respect of the research carried out on this 'unique remnant of ancient Earth's crust', the 'Archaean Barberton Greenstone Belt' was included by the International Union of Geological Sciences (IUGS) in its assemblage of 100 'geological heritage sites' around the world in a listing published in October 2022.

The outcrops of the Barberton Greenstone Belt had previously been inscribed on UNESCO's list of World Heritage Sites in 2008 as 'Barbeton Makhonjwa Mountains.