Geology Reference
In-Depth Information
(a)
(b)
Figure 11.2.
Split boulders at (a) Devil's Marbles, Northern Territory; (b) in the Mt Kosciusko area of
New South Wales, showing a split divergent from an earlier injected vein or sill.
pre-existing latent joint. In any case, the occurrence of split rocks in cold and warm humid regions
precludes this mechanism as of general application. Also, bearing in mind the large volumes of
rock involved, the essentially superficial nature of insolation changes, and the poor conductivity of
rocks, it seems doubtful whether heating and cooling alone, even aided by rain showers, could
achieve the splitting of large homogeneous masses, though cobbles and pebbles are evidently so
affected. Some writers attribute split rocks to pressure release, but the geometry of the split blocks,
their size and likely accumulated stress, and the general history of boulder development render
this suggestion unlikely.
