Saturday, September 24, 2011

Two Generations of Erosion


At many location along the Venus Bay beaches, you can see two generations of erosion on the one dune face. The upper erosion scarp (a geological term for the small vertical face, escarpment, created when waves washed away some sand)  has itself been partly eroded. As the sand face dries out it becomes unstable and collapses along wind picks up other dry sand and piles it infront of the face. Re-grown of saltbush grasses help stabile the sand collecting infron of the dune. Eventually the scarp itself will dissapear and the dune just have a steep front face. The recent erosion can be seen at the base as a new vertical face, with a areas where blocks of unstable sand have already tumbled from the sand faces above.

REMEMBER: These sand faces are remain very unstable, even if they sometimes look dry and stable.Even just a single square meter of wet sand will weigh close to 2 tonnes enough to fatally bury an adult. So children (even grown up ones) must be discouraged from playing on such erosion scarps

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