In the Lower South-East, dolomite has been formed by metasomatic replacement of bryozoal limestone in close proximity to faults. The dolomite is usually pink and of variable hardness and texture. Dolomitisation is irregular and unpredictable, and dolomite passes vertically and laterally into white, highly calcareous bryozoal limestone of the Oligo-Miocene Gambier Limestone.
Sibelco Australia Ltd now operates the former ACI quarry in an irregularly dolomitised zone adjacent to the Tartwaup Fault, 5 km east-southeast of Tantanoola. The quarry was originally opened to supply rail ballast and other construction materials, but the dolomite has been used for glassmaking flux since 1961. Quarried rock is screened, crushed and blended to give a -3 mm product with an average grade of 42% MgCO3. About 32 000 t/year are trucked plants for use as flux in the manufacture of plate glass. Agricultural dolomite is produced as a by-product.
Dolomite similar in type and composition occurs between Burnda and Compton near Mount Gambier, and a number of irregular lenses arranged en echelon within Gambier Limestone mark the trace of the Nelson Fault over a distance of 2 km in the hundred of Caroline, 30 km southeast of Mount Gambier.
Dolomite occurs in a solid solution series with ankerite (CaFe(CO3)2). When small amounts of iron are present, the dolomite has a yellowish to brownish colour. Dolomite and ankerite are isostructural. Kutnahorite (CaMn(CO3)2) also occurs in solid solution with dolomite. When small amounts of manganese are present, the dolomite will be coloured in shades of pink.
At Gz you will find a sculpture and plaque and some amazing views.
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Question 1 What is the stone used in the top half of the sculpture? What colours are present in this stone?
Question 2 What Type of stone is used in the bottom half of the sculpture? What colours are present in the stone?
Question 3 What element causes the difference in the colours of the two stones?
Question 4 What is the other stone that the artist works with? Is this stone used in this sculpture?
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