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Diamond Mining in the Namib Desert

The Skeleton Coast of the Namib desert truly is a geologist's paradise!
The bedrock, consisting of PreCambrian gneisses and schists, is overlain by variable thicknesses of sands carried from the Orange River by longshore transport and onshore winds.
These spectacular dunes, however, are but a nuisance to the miners, so CDM maintains the World's largest private earthmoving fleet in order to remove the sand down to bedrock ...


Once the sand overburden is removed, the 'basement' consists of deep gullies (left) carved by the surf at the time these now raised beaches were in the surfzone. These gullies are generally perpendicular to the coast and often have deep potholes in them. Gravels at the bottom of the gullies and in the potholes are the favorite sites for diamonds, which are found by the Ovambo mining crew using toothbrushes to do the final cleanup.

Below, from left to right: close-up of bedrock (glasses for scale)
bedrock and gullies, and a sampling trench (manmade)




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When sealevel remained stable for an extended period, it would cut seacliffs (left) along the shore. Now, these cliffs terminate the raised terraces and are characterized by smooth concave undercuts. In our offshore geophysical surveys, we also found buried seacliffs, indicating a complex sequence of fluctuating sealevels and/or regional uplift.
The coast is very rugged, with rocky coves and pocket beaches midway between Oranjemund and Luderitz, and high dunes further north. Because this is 'Sperrgebiet' (off-limits), we caught hundreds of lobsters reaching directly from the longshore rockledges into the cold waters of the Benguela Current