HALE

WILLIAMSTOWN - SOUTH AUSTRALIA

MICA MINE

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GEOLOGY

SOUTH AUSTRALIA

Located in the Houghton inlier

Emeroo Subgroup

Fluviodeltaic sandstone, conglomerate, siltstone and minor dolomite.

ADELAIDE GEOSYNCLINE

Aldgate Sandstone

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.

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Barossa Complex

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, 

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Pegmatite, undifferentiated

The

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QUARTZ VEINS

Rose Quartz, Quartz with Mica and Quartz with Goethite. 

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ALCOVES

The

POTHOLES

The

BMS Syndicate MICA MINE

The BMS Syndicate mica mine began operations in 1944, The mine has cut through a pegmatite vein within the schist of the Barossa Complex and consists of two open-pit mines none are of high significance.

No other information has been documented on this location, the only known information comes from the SARIG geology database.

REFEreNCES

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. 

GHOST RANCH
NEW MEXICO, U.S.A
TROPICAL STORM ISAIAS
MARYLAND, U.S.A
BORAH FAULT SCRAP
IDAHO, U.S.A