Ancient sand dunes
You can see examples of cross-bedding in the beehive-like domes on top of the
range. They are evidence that the Mereenie Sandstone was originally sand dunes.
Cross-bedding is very common in rocks that originated as desert sand dunes. The
wind deposited sand in different directions over a period of time.
Cross bedding can also be seen in tidal environments but the layers are much
thinner.From dunes to rock
Central Australia was a windswept plain covered with sand dunes 400 million
years ago. A huge amount of sand accumulated.
The region gradually subsided under all the weight, compressing and compacting
the bottom layers. Silica-rich water inundated the sand and cemented the grains
together. |
