Sedimentology of the Brooklands Formation, Zimbabwe: Development of an Archaean greenstone belt in a rifted graben

The Brooklands Formation, part of the ca. 2800–2900 Ma Mtshingwe Group, contains a wide variety of sedimentary and volcanic rocks. These include coarse breccias, thought to have been laid down by debris flows or avalanches; conglomerates, siltstones and shales, and banded ironstones, as well as komatiitic basalt and komatiite flows. The sequence was probably laid down on 3500 Ma old gneissic crust, at one margin of a late Archaean graben.