Geology > Pre-Karoo > Waterberg Supergroup (and Soutpansberg Group)

Waterberg Supergroup (and Soutpansberg Group)

Introduction

The underlying rock formation derives from the Kaapvaal craton, formed as a precursor island roughly 2.7 billion years ago. This crustal formation became the base of the Waterberg, which was further transformed by upward extrusion of igneous rocks. The original extent of this rock upthrust involved about 250,000 square kilometers, and is sometimes called the Waterberg Supergroup.

Sedimentary deposition from rivers cutting through Waterberg endured until roughly 1.5 billion years ago. In more recent time (around 250 million years ago) the Kaapvaal craton collided with the supercontinent Gondwana, and split Gondwana into its modern day continents. Waterberg today contains mesas, buttes and some kopje outcrops. Some of cliffs stand up to 550 meters above the plains, with exposed multi-coloured sandstone.

More information concerning the Waterberg includes:

•	Thickness range from 2700 – 7000 m or more.

•	Consists of rudites, arenites and lutites.

•	The rocks are greyish-red, red sandstones, shales and conglomerates.

Geohydrology

•	Groundwater occurs in fractures and shear zones. Unfortunately, not always high yielding enough to maintain significant withdrawals.

•	Favourable formation for groundwater is eroded sides of diabase plates.

•	In Lephalale area high yielding artesian boreholes, high in fluoride.

•	In N-Cape Matsap Formation – quartzites covered with Kalahari sands. Water table very deep, water very scarce except in few valleys in Langeberge.

waterberg