26 October 2012

Friday fold: South African gneiss

Posted by Callan

Martin Bentley* submitted this week’s Friday fold(s):

Click to enlarge

This outcrop appears on a:

road cutting between the towns of Eshowe and Nkandla, in KwaZulu-Natal, South Africa. Some very nice folds are exposed, in particular some small-scale parasitic folds in places.

This part of the country falls into the Natal Metamorphic Suite, in particular the Khomo Formation of the Nkomo Nappe.

My resources are unfortunately limited, but I believe that this is a foliated melanocratic amphibolite formation.

Site coördinates are 28°50’27.03″S; 31°11’12.58″E, but nothing is visible in Google Earth. The outcrops in this part of the world are generally pretty bad (lots of rolling hills covered in vegetation), but similarly aged rocks are found in the Northern Cape, and are much better exposed there. They together form the Namaqua-Natal Metamorphic Suite, and are dated to around 1.2Ga.

Some more… Martin’s wide-brimmed sun hat appears as a sense of scale.

Thanks, Martin! Happy Friday!

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* We’re not sure if we’re related or not. We have genealogists looking into it.