Zonality, azonality, and the coastal context - Landforms and Geology of Granite Terrains - page 290

(c)

(d)

Figure 12.1. (c) In sandstone in the Colorado Plateau (Bradley, Hutton and Twidale, 1978); (d) cutting

across columnar joints in dacite, Gawler Ranges, South Australia.

1995), and in Ayers Rock, central Australia; and in conglomerate in The Olgas, also in central
Australia, in the Meteora complex of central Greece, and in the Mallos de Riglos and Montserrat
in the vicinity of the Pyrenees ( Fig. 12.3) . The Gawler Ranges, South Australia, a massif devel-
oped in ignimbritic dacite and rhyolite, is subdivided into large orthogonal or rhomboidal blocks
(Fig. 12.2b), and comprising numerous bornhardts, many of them bevelled ( Figs 12.3d and e).
The marginal steepening of granitic bornhardts resulting in their conversion to koppies is due
to peripheral subsurface weathering, most dramatically manifested in flared slopes; and a similar