By: Nick, Tebogo, Penester and Khaya
Tebogo
showing that the diamictites can be your friend in certain circumstances!
Well only in the Richtersveld perhaps, and only on another
sun-drenched day, but after the singular (but expected!) non-success in earlier
diamond quests among Orange River gravels, team attention went beyond the
terraces to the rocks just above the basement of the last few days. The barren
landscape is often almost surreal with quartz-covered plains contrasting with
the dark desert varnish-covered outcrop ridges, though the geology today was
relatively consistent overall. Largely Kaigas diamictite, with variably-sized
clasts throughout, in this area the largest being carbonates along with various
granitoids. The fine-grained matrix is generally sheared, with spaced phyllitic
zones a feature, forming knife-edged outcrops protruding through the prevailing
scree. The contact zone with the basement granodiorites and conglomerates and
siltstones of the Vredefontein Formation is however marked by a gap in outcrop
rather than spectacular thrust.
Clockwise
from top left: the thorn among the roses; the contact between the basement
granodiorites in the left foreground and the metasediments of the Vredefontein
Formation; the zone proximal to the thrust though is marked by numerous quartz
veins; a drawback of removing your boots during lunch break is that they may
disappear!; you’re not looking for these boots are you?
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