Mudrocks

Introduction: Mudrock is the general name for the finest grained clastic sedimentary rocks, usually silt and clay-sized particles occurring together. They are formed when fine clay and silt particles come to rest under water. The wind also deposits these granules. Claystone, siltstone and shale are types of mudrock. If a particular mudrock is composed of only clay-sized particles, then it is called claystone. If the composition is of only silt-sized particles, it is called siltstone. Layered mudstone is called shale. Wind-blow mudstone is called loess.

Distribution: Common in geological formations throughout Namibia, especially in parts of Waterberg and the Toscanini region. There is extensive mudrock/shale interbedded with sandstone in the Nama Group of rocks in southern Namibia.

Composition: Fine clay and silt particles.

Colouration: Shale is either yellow, red, grey, green or black.

Uses: Shale is broken up and used for making bricks and cement.