20x magnification: Hematite stained drusy quartz on Jasper and Goethite.
Sand: Strzelecki Track
20x magnification.
Immature lithic sand from silcrete deposit containing clear rounded quartz, jagged clear quartz, orange gypsum, calcium rich siltstone, chips of purple quartzite, goethite. Notable absence of silcrete as it highly resistant to weathering.
Banded Siltstone: Copley
Magnified 20x
Botryoidal Goethite
Magnified 20x
Limonite included Quartz
Magnified 20x
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 catalogue: LC.library.geology.catalogue
Stromatolite Horizon Layer 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.
Sand: West of Copley
Lithic sand collected on a field trip to the hills west of Copley containing a small amount of clear quartz with fragments of assorted parent rocks – claystone, iron oxides, and coloured siltstones and sandstones.
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.
Hematite Pseudomorph after Pyrite
Iron oxide cubes found in a dolomite formation on the NW side of Leigh Creek commons.