E2 Mount Cottrell - Eruption Point

This information has been developed from the publications:

Sites of Geological and Geomorphological Significance in the Western Region of Melbourne (1986) by Neville Rosengren
Sites of Geological and Geomorphological Significance on the Coast of Port Phillip Bay (1988) by Neville Rosengren.
Sites of Geological and Geomorphological Significance in the Shire of Otway (1984) by Neville Rosengren.

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.

Location	Eyensbury - 905175. Shire of Melton. 4.5 km southeast of Melton Reservoir.	E2 - Mount Cottrell, one of the most voluminous of the lava sources for the Werribee Plains.
Access	Greig Road, Mount Cottrell Road.
Ownership	Private land.
Site Description	Mount Cottrell is a volcanic cone formed by the radial eruption of numerous lava tongues, with no intervening pyroclastic eruptions. The flows are symmetrically distributed around the vent producing a cone of geometric shape. Although achieving a height of only 200 m, the cone is of considerable bulk with flows extending almost 10 km to the south. The massive nature of this basalt cone is not readily appreciated when viewed from close quarter, but is readily apparent when seen from a distant point such as the You Yangs. The slopes are of low angle, apart from those at the summit where a hard dense basalt bluff 5 to 6 m high surrounds a shallow crater. The surface of the basalt dips toward the crater at generally low angles, except for the north sides where dips reach 30^o.
Significance	Regional. There are two aspects to the significance of the site - the specific nature of the bluff and crater at the summit, and the extent of the radial flows. The cone is the most massive of the Werribee Plains volcanoes and gave rise to a number of distinct lava flows. The basalt rim is of particular interest as it has similarities to the cappings on the volcanoes of the Gisborne area, although Mount Cottrell is a much younger eruption point than these. The flows from this point towards the west influenced the course of the Werribee River and may have dammed the stream near the junction of the Djerriwarrh Creek.
Management	Class 2. The basalt rim and upper slopes of the volcano should not be quarried or be built on by other farm service buildings. Further residential or industrial building should not be permitted above the 170 m contour.
References	Condon, M.A. (1951). The Geology of The Lower Werribee River, Victoria. Proc. R. Soc. Vict. 63:1-24

Related sites on VRO

Eruption Points of the Newer Volcanics (Rosengren 1994) - Mount Cottrell

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