The Sisters (Terang)

This information has been obtained from the report: Eruption Points of the Newer Volcanic 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 The review of eruption points was based on an earlier unpublished manuscript Catalogue of the post-Miocene volcanoes of Victoria compiled by O P Singleton and E B Joyce (Geology Department, University of Melbourne 1970).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 value. Reference should be made to the most recent reports. See the Earth Science Heritage (external link) section of the Geological Society of Australia website for details of geological heritage reports, and a bibliography.

Location:	38 11 53S 142 46 10E (external link); 7421-1-3 (The Sisters) 577716. 11 km NW of Terang. Sisters Road.
	Mortlake.
Land Tenure/Use:	Private land. Grazing. Sisters Road gives view of the crater.
Type 8:	Nested/buried tuff ring maar.
	The Sisters are a group of scoria cones and mounds nested in a tuff ring with a largely infilled crater 1.5 km across. A smaller tuff ring is located 500 northwest of the main crater. The main tuff ring is best preserved around the southeastern edge of the site where it forms a curving ridge almost 30 m high. Bedded tuff is exposed in a disused pit adjacent to Sisters Road. The maar is now covered with scoria and this forms The Sisters Hill (203 m) and a conical mound adjacent to Framlingham Road. The site contains a well-defined enclosed central crater of irregular outline and almost 20 m deep. The second maar is between Framlingham Road and Londrigans Lane and is defined by a circular swamp surrounding a small accumulation of scoria.
	A lava flow from The Sisters, retaining original stony rise surfaces, gave a K-Ar date of 0.57 +/- 0.03 million years.
	200+ m; 55 m.
State:	A good example of a nested maar with a well-defined crater. It is significant as it forms part of the series progressing from simple maar craters and tuff e.g. Keilambete, to maars completely buried by scoria and lava e.g. Shadwell.
Class 2:	Reopening of scoria and tuff quarries on a limited scale and low on the slopes rather than on crests would not compromise the significant geological and geomorphological values of the site. It is important to retain the intactness of the main crater.
References:	McDougall, I., Allsopp, H.L., & Chamalaun, F.H. 1966. Isotopic dating of the Newer Volcanics of Victoria, Australia and geomagnetic polarity epochs. Journal of Geophysical Research 71, pp. 6107-6118.0.

Page top