Between a Rock and a Hard Place

Science Snap (#28): Brandberg Massif, Namibia

Brandberg Massif

The 120 million year old Brandberg Massif, Namibia. Image credit: NASA

Brandberg Massif is Namibia’s highest mountain, but if you look from above, you’ll notice it’s no ordinary one. Brandberg is a single mass of granite that pierced its way through the Earth’s crust into the Namib Desert. Looking at the Landsat 7 image, Brandberg is a circular dark and steep-sided mountain, imposing itself over the desert below. It reaches height of 2.5 km and stretches across 31 km.

Nowadays, the landscape is geologically quiet but the Brandberg intrusion formed over 120 million years ago and marks a period in the Earth’s history where volcanism was rife due to the break up of the supercontinent Gondwana. The majority of the Massif is composed of homogeneous medium grained biotite-hornblende granite. However, to the west there is a 2 km diameter pyroxene-bearing monzonite and in the south it is crosscut with arfvedsonite granite dykes and sills. As the Massif protrudes from the landscape, it influences local climate by drawing in the rains. The rain then percolates through the granites and washes out through springs.

Apparently, if you reach the granite for sunrise or sunset, you’ll see it glow red under the suns rays. Appropriately, the locals call it Daures, “the burning mountain”.

Elspeth is currently undertaking a PhD in Geology at the University of Bristol. Her research focuses on understanding the mechanisms of ground deformation seen at a number of Kenyan Rift volcanoes. Elspeth tweets as @eamrobertson.