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Akurra Trail: Leigh Creek

The Akurra trail is a 10.5km (4hr) walk from Leigh Creek township to the picturesque Aroona Dam. Commencing at the health clinic, the path is clearly signposted and includes cultural information. It traverses the magnesite rich Myrtle Springs Formation, the colourful ridge of the Skillogalee Formation, and into the towering dam walls of the Copley Quartzite Formation.

Trail map can be downloaded, and you can also pick up an informative brochure at the Leigh Creek supermarket. On your way back, you can drop into the Leigh Creek Library geological display of local rock and mineral samples.

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Iron-rich tillite

The dark bands seen between the rock layers are goethite, an iron oxide mineral that forms through the oxidation of iron-rich fluids along bedding planes or fractures in the rock.

Located within the Merinjina Tillite Formation, the smaller embedded rocks were likely deposited in this massive matrix by glacial activity. This tillite has since undergone oxidation, and in some areas, has been partially replaced by botryoidal goethite—a rounded form of iron oxide.

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Goethite boulders

This group of goethite–quartz boulders may have formed from a hydrothermal seam or vent, where silica and sulfur-rich fluids precipitated quartz and pyrite.  As pyrite oxidizes, it typically forms sulfuric acid, which accelerates iron oxidation, in this case forming goethite. As the surrounding blocky shale erodes, the more resistant goethite-quartz boulders remain – a common sight in the Flinders Ranges.

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Yellow sellar slug

This shell-less terrestrial gastropod mollusc appears to be a yellow sellar slug (Limacus flavus), originating in Europe. Seen in the Flinders Ranges, attended to by isopods in an unknown capacity.

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Stinkwort

Dittrichia graveolens, known as stinkwort or stinking fleabane, is native to southern Europe, North Africa, and western Asia, now naturalized in Australia. It is considered and noxious weed and invasive species in some places. It can damage the digestive tracts of grazing animals and contact can cause severe dermatitis in humans. Seen flowering in gullies and creeks in the north Flinders Ranges during autumn.

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Moro gorge limestone formations

Moro Gorge is a cascading series of spring-fed waterholes located in the Nantawarrina Indigenous Protected Area in the northern Flinders Ranges. The surrounding limestone walls appear to have precipitated from mineral-rich spring water, forming tufa columns and flowstone. Calcrete is also present in the area—a type of limestone conglomerate consisting of pebbles bound within a calcium carbonate matrix.

Moro Gorge from above
Limestone cave with flowstone formation
Calcrete
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Muddy limestone turbidite: Nantawarrina

Muddy limestone turbidite, formed from sediment deposits in offshore silty waters during the Cambrian period (around 550 million years ago). The dramatic localised buckling seen here may have occurred in situ during a turbulent underwater event. This rock is part of the Mernmerna Formation in the northern Flinders Ranges.