Colours of the Pilbara - Joffre shales

These lovely rocks are shales from the Joffre Member in the Brockman Formation of the Hamersley Group. The shales are approximarlty 2459 million years old. They are not usually these lovely blue, gold and purple colours. They display a slight hydrothermal alteration and it is likely their proximity to the BIF within the Brockman Formation has resulted in the precipitation of minerals leached from the iron ore.

The big bolder in the centre of the image is approximatly 1.5 feet long preventing me from rock-nabbing it and taking it home for my collection.

Fossils - Pecten fossil

Pecten from the Naracoorte Limestone - photographed with an iphone through a 10x hand lense.

This tiny tiny shell was found by one of my students from JMSS while we were doing a palaeontology practical exercise at the Naracoorte Caves. He was sorting through some cave sediments which has been retrieved from a cavity found in a nearby quarry. Due to the nature of the discovery, dating these items through stratification was impossible, so they have been used to give the location an assemblage database and are used to educate school groups. Most of the fossils come from small mammals and reptiles with the occasional Megafauna bone or tooth as well. The cave fossils are less than half a million years old.

This pecten comes from the Naracoorte Limestone, which is a member of the Mt Gambier Limestone Formation. The MtG has been dated to between 24 - 33 million years old. It's amazing to think this pecten is still is almost perfect condition and has survived this long!