Ferntree Gully is a suburb in Melbourne, Victoria, in the Dandenong Ranges, 32 km east of Melbourne's CBD
This location is the site for the former quarry that is on the edge of the rhyodacite geology that forms the Dandenong Ranges. Elevations of the natural ground level vary from 127 m in the western corner to 216 m on the marked knoll. The natural soil is a light grey loam over clay subsoil.
It is here that lies an ancient volcanic complex of the Dandenong Ranges. Travelling through the Dandenongs, the many road cuttings expose the dominant rocktype of the area, a rhyodacite. Along the margins of the rhyodacite, contact metamorphism of marine sediments has formed hornfels. At this location, hornfels is still visible in the cliff faces around the quarry.
When this site was an active quarry, it was an ecological desert. Now with effort, the location is great with planted trees provides protection for local wildlife.
A quarry is a place from which dimension stone, rock, construction aggregate, riprap, sand, gravel, or slate has been excavated from the ground. A quarry is the same thing as an open-pit mine from which minerals are extracted. The only trivial difference between the two is that open-pit mines that produce building materials and dimension stone are commonly referred to as quarries. The word quarry can also include the underground quarrying for stone.
Rhyodacite with Brachiopod Impressions
Rhyodacite is an extrusive volcanic rock intermediate in composition between dacite and rhyolite. It is the extrusive equivalent of granodiorite. Phenocrysts of sodium-rich plagioclase, sanidine, quartz, and biotite or hornblende are typically set in an aphanitic to glassy light to intermediate-colored matrix. Rhyodacite is a high silica rock containing 20% to 60% quartz with the remaining constituents being mostly feldspar. The feldspar is a mix of alkaline feldspar and plagioclase, with plagioclase forming 35% to 65% of the mix. Rhyodacite often exists as explosive pyroclastic volcanic deposits.
Q1 At the listed coordinates you will be standing at the viewing deck for the quarry escarpment on the opposite side. Describe the colours you see.
Q2 At WP2, describe the rock colour and texture. Also, what do you think has happened the significant 'marking' in this rock clearly located on the path side of the rock?
Q3 At WP3 what is the shape of the rock that is located in the garden area?
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