Geology Reference
In-Depth Information
(a)
(b)
Figure 7.5.
Castle koppies: (a) Haytor, Dartmoor, southwestern England; (b) in the Andorran Pyrenees.
of southern Galicia NW, Spain (Vidal Romaní, 1989) and northern Portugal (Vidal Romaní, Brum,
Zézere, Rodrigues et al., 1990) and in many other places, castellated granite inselbergs are associated
with orthogonal joint systems. But not all granites with well-developed orthogonal joint sets give
rise to castle koppies. In parts of the Pyrenees (Vidal Romaní, Vilaplana, Martí and Serrat, 1983),
though koppies occur on summit plains and crests in Andorra for example, they are absent or
scarce elsewhere, even in what appears to be suitably structured rocks. If castle koppies were
consistently developed where orthogonal fractures are prominent, they would be widely distrib-
uted, whereas they are, perhaps, the least common of the three inselberg forms discussed here.
Many of the koppies of Zimbabwe are developed on gneisses with a well-developed, steeply-
dipping, widely-spaced foliation. Gneissic koppies also occur in the eastern Mt Lofty Ranges, near
Adelaide, South Australia, and in the southwest of Western Australia, e.g. in Castle Rock, in the
