Wooltana Volcanics: Arkaroola

Volcanics are not a common sight in the Flinders Ranges but an example of Wooltana Volcanics is visible on the Paralana Hot Springs Road at Arkaroola. The role of volcanic activity in the formation of the Flinders Ranges is outlined in the essay Legacy of Time by the Royal Geographical Society of South Australia.

Ripple rocks: Arkaroola

Ripple rocks seen throughout the Flinders Ranges are likely to have been formed in sandy shallow waters, rapidly covered in kilometres of sediments which resulted in rock formation through processes of heat and pressure. This example is part of the Blue Mine Conglomerate Formation, around 800 million years old.

Blue Mine Conglomerate Formation: Arkaroola

An outcrop of Blue Mine Conglomerate Formation can be seen at Kingsmill Creek near the Arkaroola Homestead. This conglomerate was formed around 800 million years ago and contains fragments of blue quartz from the 1.59 billion year old Mount Neil Granite Formation seen closer to Paralana Hot Springs. The Blue Mine Conglomerate was likely formed from shoreline or fluvial deposition and is seen at this site as a weathered pavement surrounding a waterhole.

Conglomerate containing blue quartz

Opaminda Formation: Arkaroola

This Opaminda Formation near the Arkaroola Village was deposited in shallow waters around 800 million years ago. This lightly metamorphosed outcrop exposes ripple marked sandstone, laminated and a green talcose siltstone (pictured).

Pink Dolomite: the Nuccaleena Formation

The Nuccaleena Formation is a narrow pink dolomite layer that is frequently found in outcrops across the Flinders Ranges, and is described as being a good ‘geological marker horizon’.

This Nuccaleena Formation outcrop, just 5m wide, is seen in Parachilna Gorge, between the Brachina Formation siltstones and the older calcereous Elatina and Trezona Formations.

Read more about the formation of the Flinders Ranges in The Legacy of Time.

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