Geology Reference
In-Depth Information
6
Inselbergs and bornhardts
6.1 DEFINITIONS AND TERMINOLOGY
Inselbergs are ranges, ridges and isolated hills that stand abruptly from the surrounding plains, like
islands from the sea (Figs 1.2e, 1.3a and b, and 6.1a). Early English-speaking explorers referred to
them as island mounts (Toit, du 1937; Willis, 1934), but the comparable German term, Inselberg,
in other languages with the upper case initial letter dropped , has gained general cur rency in the
technical literature (Bornhardt, 1900; Jessen, 1936). Some of these residuals are spectacular fea-
tures and whether built of g ranite or of some other rock type, those located in deser t and semi-
desert regions, where they can be seen from afar and in toto, have a dramatic visual impact. Thus,
so erudite and civilised a person as van der Post (1958, pp. 181-182) could write of the gneissic
Tsodilo or Slippery Hills of northern Namibia that they rose “sheer out of the flat plain, and were
from the base up made entirely of stone, and this alone, in a world of deep sand, gave them a sense
of mystery”. Tall, steep-sided hills like the Pão de Açucar of Rio de Janeiro, Brazil, are no less stu-
pendous, for though there are other prominent domical for ms nearby, their very size and abrupt
(a)
Figure 6.1. (a) Literal as well as littoral inselberg: some of the Cíes Islands, western Galicia, at the mouth of
Vigo Ría showing marked asymmetry with cliffed slopes facing west, the dominant wind and
forced wave direction.
