Geology Reference
In-Depth Information
Ya rwondutta Rock, northwestern Eyre Peninsula, South Australia. Unfortunately, it is unlikely that
the necessary high speed flows develop on the outcrops under review.
8.6.3
Surface or subsurface initiation?
The arguments concerning the relative importance of mechanical and chemical processes in the
development of gutters are interesting
per se
, but are also linked with the question of their initiation,
for there are strong indications that some of the forms, at least, originated at the weathering front.
In 1849 Logan reported deep grooves developed in granite on Pulau Ubin, an island at the east-
ern end of the Johore Strait (Fig. 8.21). He reported similar features from uplands in the southern
part of the Malay Peninsula. On Pulau Ubin many of the granite blocks exposed on the beach were
(a)
(b)
Figure 8.21.
(a) General view of fluted block at Pulau Ubin, Singapore. (b) Detail of fluting on nearby Frog
Island (Pulau S'kodo or Sekudu).
