Geological formation: sedimentary deposits

This striking outcrop near Copley exhibits a range of sedimentary deposits. From the north to south, green shale and blocky siltstone meets weathered sandstone. This is followed by a distinct tillite layer between two dolomite layers, and a thin layer of quartzite. Further along, siltstone layers coloured by iron oxide, and more weathered sandstone.

Weathered sandstone.

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Geological Exhibit at Leigh Creek Library

After many months in the making, the new geological exhibit for the Leigh Creek Library is now on display.

The collection contains 99 rock and mineral specimens, primarily from the Flinders Ranges, Gammon Ranges and Strzelecki Track area, along with a handful of interesting samples from Broken Hill and WA.

A full catalogue of the collection is available for download below. The display can be viewed from 8:30 – 4:30 on weekdays, Friday evenings and Saturday mornings (closed until 1pm on weekdays during school holidays).

Download catalogueLC.library.geology.catalogue

 

Stromatolite Seam in Magnesite

An old mine exploration site offered an interesting opportunity to walk through the layers of magnesite rich dolomite near Copley.

Between layers of white magnesite, and light and dark dolomites is a gnarly seam of fossilised stromatolites.

Geological formation: West of Copley

A trip to the hills west of Copley revealed a fascinating array of sedimentary rock formations. Within an approximate 100 metre square area, extensive layering was apparent. Dolomite layers were dominant to the south, typical of the local magnesite bearing formation. Within these layers were granular conglomerates with silicified seams.

Further along to the north were finely banded dolomites.

Evidence of glacial deposits was seen in tillite, pebbly layers and a course sandy / silty matrix.

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