Tuesday, 14 August 2018

Australian Fossil Mammal Sites (Riversleigh / Naracoorte)

This UNESCO site is located in two different places in Australia.

Riversleigh Fossil Mammal Site
This postcard was sent by Penny

Fossils at Riversleigh are found in limestone by lime-rich freshwater pools, and in caves, when the ecosystem was evolving from rich rainforest to semi-arid grassland community. Some of the fossils at Riversleigh are 25 million years old. High concentrations of calcium carbonate has meant the fossils are extremely well preserved. The fossil collection reveals mammalian evolution across a time span of more than 20 million years. There are more than 200 individual locations where fossils have been found. The fossil record here is significant because it provides evidence on evolution and the distribution of species across Gondwana.
Thirty-five fossil bat species have been identified at the site, which is the richest in the world. Cave deposits have been particularly rich in bat species. - in: wikipedia

Naracoorte Caves
This postcard was sent by Xue

Naracoorte Caves National Park is a national park near Naracoorte in the Limestone Coast tourism region in the south-east of South Australia (Australia).
The limestone of the area was formed from coral and marine creatures 200 million years ago and again 20 million years ago when the land was below sea level. Ground water since then has dissolved and eroded some of the limestone, creating the caves. The caves, such as the Victoria Fossil Cave and Blanche Cave, are often not far below ground, and holes open up creating traps for the unwary. This is the source of the remarkable collection of fossils. Mammals and other land creatures have fallen into open caves and been unable to escape. The fossil record has been preserved in strata formed from eroded topsoil washed and blown in. In some places, the fossil-bearing silt is up to 20 metres thick. Some of these areas are being preserved for future research when better methods of dating and reconstructing fossil records may have been found. These fossil traps are especially significant for tracing Australian megafauna. - in: wikipedia

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