VIMP Report 26 - The geology and prospectivity of the Murrungowar 1:100 000 map area, Eastern Victoria
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Product description:Download The downloadable version of this report is supplied in PDF format. Abstract This report describes the geology of the area covered by the Murrongowar 1:100 000 mapsheet in eastern Victoria. It gives a comprehensive account of the geological history, Palaeozoic and Cainozoic rock units, structural, metamorphic and economic geology and of the geophysical information, together with an extensive list of references. The region lies in the eastern part of the Lachlan Fold Belt and covers the southern portion of the Mallacoota structural zone. Exposure is generally much poorer than in the mountainous terrain further north, and in the south the Palaeozoic rocks disappear under Tertiary subaerial and marine sediments. The oldest rocks are Ordovician and are part of a sheet of turbidites and black shales that cover much of the eastern Lachlan Fold Belt. The older Pinnak Sandstone (Lower Ordovician) forms the bedrock over most of the area and consists of thick to thin bedded quartz-mica turbidites and siltstones with occasional intervals of thin bedded grey chert. The overlying Bendoc Group (Upper Ordovician) is only preserved as fault bounded slices in a number of fault zones. It consists of three formations; Sunlight Creek Formation, thinly bedded black siliceous shale chert and fine sandstone; Warbisco Shale, black siliceous shale and Akuna Mudstone, black to grey mudstone. The Lower Silurian Yalmy Group is also represented by a few fault slices with only units 2 (predominantly siltstone) and 3 (fine grained quartzitic turbidites) present. A thin fault bounded sliver of limestone found in drill core is described formally for the first time. Several outcrops of Lower Devonian volcanic rocks with close affinities to the Snowy River Volcanics are also represented. These are unconformably overlain by the Upper Devonian Combyingbar Formation which comprise fluvial conglomerate, sandstone and red mudstone. The Lower Palaeozoic rocks are overlain by an extensive sheet of Tertiary gravels which cover much of the southern part of the mapsheet. Granites form a significant part of the area. All those outside the Kuark Metamorphic Complex are I-Types, while those in the complex are a mixture of both S and I types. These are discussed and described in detail. The central part of the mapsheet is occupied by the Kuark Metamorphic Complex which comprises biotite phyllites and schists, andalusite and cordierite schists, K-feldspar and sillimanite schists and gneisses, migmatites and syntectonic granites. These have been divided into a number of metamorphic zones defined by isograds based on the distribution of metamorphic index minerals, namely biotite, andalusite and cordierite and K-feldspar and sillimanite. The area has been affected by at least four deformation episodes represented by:
The economic geology of the region is discussed in a number of sections covering mineral exploration, mining history, mineralisation style and economic potential and prospectivity. Bibliographic reference Hendrickx, M.A., Willman, C.E., Magart, A.P.M., Rooney, S., VandenBerg, A.H.M., Oranskaia, A. & White A.J.R., 1996. The geology and prospectivity of the Murrungowar 1:100,000 map geological report. Victorian Initiative for Minerals and Petroleum Report 26. Department of Natural Resources & Environment. Related products:
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