Geology Reference
In-Depth Information
(a)
(b)
Figure 7.2.
(a) Sketch of the Swakop valley in central Namibia, showing nubbins in valley floor, domes at
higher levels, and palaeosurface (X). (b) Nubbins developed in wet valley-floor site in
Namaqualand (Western Cape Province), South Africa.
Figure 7.3.
Sheet fracture exposed in gneissic nubbin, western Pilbara, Western Australia.
that the contrast between the dome and nubbins is not due to petrological characteristics. Moreover,
both sheet fractures and orthogonal fractures are present.
At several sites sheet structure is preserved and domical forms can be seen beneath the outer
cover of blocks and boulders (Fig. 7.3) suggesting that nubbins are domes, the outer shells of
