One of the more mysterious geological occurrences is the surface vitrification observed coating may rock outcrops.
In the Kimberley region of Western Australia ancient rock paintings known as the Bradshaw Paintings are covered by a thin silicious coating that has permanently fused the painted art onto the rock surface, making this art particularly fire-resistant.
Modern aboriginal paintings are, on the other hand, directly painted and soon show the effects of weathering.
The sandstones in the Kimberley region are also coated with a surficial vitrification, a feature that can be observed elsewhere in Australia, such as Arnhem Land, and the Hawkesbury sandstone of the Sydney Basin that has been described as a quartzite, but at depth is actually in a state of wet plastic, a fact I stumbled on when supervising a diamond drilling operation testing the location of a fault interpreted in the geological analysis of a proposed railway tunnel…
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