Victorian Resources Online - Corangamite

Red Rock (Alvie)


Red Hill
Image:  Euption Point, Red  Rock (Alvie)
Red Rock (Alvie) viewed from the southeast

381530S 1433000E; 7621-4-3 (Warrion) 7621-3-4 (Colac) 7521-2-1 (Nalangil) 7521-1-2 (Wool Wool) 200530. 12 km NW of Colac. Corangamite Lake Road and Red Rock Road.

Colac

Mainly private land.

Lake surfaces are public land. Public road to two lookouts. Four sets of operating and disused quarries into scoria and tuff materials. Extensive exposure of pyroclastic materials.

Type 8:

Nested/buried tuff ring maar.

Red Rock is one of the most complex eruption points in the Newer Volcanics Province and includes maars, tuff rings and scoria cones with a basal lava flow from another source (probably Warrion Hill). Up to 30 eruption centres have been mapped in the area measuring 4 km by 3 km just south of the township of Alvie and there are several small eruption points just north of the township. The eruption sequence includes an initial extended phase of maar and tuff ring formation with minor intervening scoria phases when phreatomagmatic activity declined due to depletion of groundwater. There are nine entire craters up to 75 m deep, some containing lakes including Lakes Purdiguluc, Werowrap and Coragulac. Lake Purdiguluc is formed by at least five coalescing eruption points. Following the maar activity there was an extended phase of scoria eruption in the north around Lake Werowrap which buried part of the maars and tuff deposits. On the basis of a single radiocarbon assay, a date of approximately 8,000 years has been advanced for the age of the Red Rock tuff eruption.

200+ m; 60 m.

International:

Red Rock is the most concentrated cluster of eruption points known in the Newer Volcanics Province. It shows a variety of eruption mechanisms and the craters and cones are in an excellent state of preservation. Ollier (1967a) advanced Red Rock as the type locality of “Red Rock Maars” - ie - overlapping multiple eruption points. Although the age is uncertain, it is clearly one of (and possibly the) most recently active volcanoes in Victoria. Of particular interest is the interleaving of volcanic ejects and lake and lunette deposits.

Class 2:

Active and abandoned quarries provide excellent sections of the volcanic ejects. Some former pit sections are now deteriorating and good geological sections are becoming obscured. Occasional clearing of old pit faces is necessary to maintain clear sections in pyroclastics. The site needs detailed study to evaluate the distribution of scoria and tuff resources that may be quarried without impairing to geomorphology of the cones and craters.

References

Skeats, E.W. & James, A.V.G. 1937. Basaltic barrier and other surface features of the Newer Basalts of western Victoria.
Proceedings of the Royal Society of Victoria 49, pp. 245-278.
Hills, E.S. 1940. The physiography of Victoria (1st edn). Whitcombe & Tombs, Melbourne.
Ollier, C.D. & Joyce, E.B. 1964. Volcanic physiography of the Western Plains of Victoria. Proceedings of the Royal Society of Victoria
77, pp. 357-376.
Ollier, C.D. 1967a. Landforms of the Newer Volcanic Province of Victoria. In J.N. Jennings & J.A. Mabbutt (eds), Landform studies from Australia and New Guinea. ANU Press, pp. 315-339.
Gill, E.D. 1978. Radiocarbon dating of the volcanoes of western Victoria, Australia. Victorian Naturalist 95, pp. 152-158.
Cas, R., Allen, R., Bull, S & Sukhyar, J 1984a. The Red Rock volcanic complex. Volcanics Workshop 1984, Monash University, Melbourne (unpubl).
Tickell, S.J., Cummings, S, Leonard, J.G. & Withers, J.A. 1991. Colac 1:50 000 map geological report. Geological Survey of Victoria Report 89.

Image:  Eurption Point, Red Rock (Alvie)
Red Rock (Alvie) viewed from the west

This information has been obtained from the report: Eruption Points of the Newer Volcanics Province of Victoria by Neville Rosengren. This report was published in 1994 and was prepared for the National Trust of Australia (Victoria) and the Geological Society of Australia (Victorian Division). The review of eruption points was based on an earlier unpublished manuscript Catalogue of the post-Miocene volcanoes of Victoria compiled by O P Singleton and E B Joyce (Geology Department, University of Melbourne 1970).

Geological heritage sites, including sites of geomorphological interest and volcanic heritage sites, are under regular revision by the Geological Society of Australia, especially in the assessment of significance and values.Reference should be made to the most recent reports. See the Earth Science Heritage section of the Geological Society of Australia website (external link) for details of geological heritage reports, and a bibliography.


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