WILLIAMSTOWN - SOUTH AUSTRALIA
Located in the Houghton inlier
Emeroo Subgroup: Fluviodeltaic sandstone, conglomerate, siltstone and minor dolomite.
The Aldgate Sandstone was deposited during the Neoproterozoic Torrensian period (600 million years old). The formation is a mix of medium coarse-grained, green, brown, and grey sandstones, and is quartzitic to micaceous and clayey. Heavy mineral layers are present along with lenticular cross-bedding and phyllite is also visible in some locations.
Conglomerate with layers of medium-sized pebbles are visible around the waterfall cemented within the Aldgate Sandstone.
The Barossa Complex was deposited (~1740 Million years ago), the complex is a mix of metamorphosed igneous granitic rocks which formed during the Mesoproterozoic (1701 Million years ago). Majority of the metamorphism also occurred during the Mesoproterozoic (1630 or1610 to 1550 million years ago), minor granite formed in the Mesoproterozoic (1578 million years ago), the introduction of pegmatite and amphibolite dikes also formed in the Barossa Complex.
The rocks have been retrogressed, this occurs during the uplift and cooling of rocks most likely formed during a mountain-building event.
Metamorphic Rocks in the Barossa Complex:
The Barossa Complex is a mix of quartzofeldspathic rocks which were metamorphosed graywacke sandstone and siltstone, greywacke is a hard, dark and poorly sorted sandstone in a clay matrix most likely deposited in a deep water setting.
The Complex has formed paragneiss which was once a sandstone or argillaceous schist, it has been recrystallized in the earth's crust and is categorised as amphibolite facies, to be put into this category the metamorphic rock must have been formed under high-temperature and pressure conditions of 500° C (950° F). It's essentially a metasedimentary rock with a texture like gneiss.
Quartzite has been found in the complex it forms from deep burial or convergent plate boundaries clashing together which metamorphosed quartz sandstone as the sand grains melted and recrystallized. Another metamorphosed rock in the complex is pelitic which is formed from a metamorphosed fine-grained sedimentary rock like mudstone or siltstone.
Layered or banded calc-silicate rocks which are calcium-rich silicate minerals are also visible in the Complex,
Rose Quartz, Quartz with Mica and Quartz with Goethite.
Bms Syndicate Mining Operations
The Bms Syndicate began operations in 1944 mining mica and beryl, The mines have cut through a pegmatite vein within the schist of the Barossa Complex, those deposits are associated with intrusive felsic phanerocrystalline rocks. The mines consist of two open-pits none are of high significance.
No other information has been documented on this location.
Victor Tokarev. (2005, February). Neotectonics of the Mount Lofty Ranges (South Australia). Adelaide University - school of Earth Science & Environmental Sciences, Geology & Geophysics.
South Australian Government. (n.d.). SARIG geological map. SARIG.
South Australian Government. (n.d.). SARIG geological map. Layers: All Mines and Mineral Deposits -> BMS Syndicate. SARIG.