Site 13 De Chene Reserve - Lava Flow Structures

This information has been developed from one or more of these publications:

Sites of Environmental Significance in the Flood Plain of the Upper Yarra Valley Region (1983) by Neville Rosengren, Douglas Frood and Kim Lowe (as part of a study of Sites of Environmental Significance by the University of Melbourne for the then Upper Yarra Valley and Dandenong Ranges Authority).

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 for details of geological heritage reports, and a bibliography.

Location:	YARRA 5000/04.09 E21670 N21075
	Disused quarry on the western (right) bank of the Merri Creek 400 metres south of Murray Road and 100 m north of the footbridge on the Merri Path.
Access:	Connolly Avenue and Merri Path.
Ownership & Municipality:	Public Land, City of Coburg (De Chene Reserve).
Site Description:	The overgrown slopes of the former quarry show a number of primary and secondary features of lava flows. The site marks the edge of a tongue of lava that filled the former valley of Merri Creek and backed up a short way into the former Edgars Creek blocking the flow from that stream. The walls of the quarry show platey and vertical jointing – the dip of the joints indicating the directions that the lava moved. Weathering of the basalt has produced rounded corestones and some joints are partly filled with secondary minerals such as limonite and magnesite.
Significance Rating:	Local.
	This site complements the tessellated pavement on the opposite side of Merri Creek and illustrates a stage in the physical development of the Coburg area. The blocking of the ancient valleys by this lava resulted in a lake forming upstream in Edgars Creek which partly filled with sediment. Edgars Creek has since then cut into this sediment and eroded a wide floodplain near the junction of Merri Creek.
Site Sensitivity:	Class 2.
	The site is not subject to degradation apart from being very overgrown and the basalt structures are now much obscured. The site should be cleared to allow the basalt faces to be seen. This is an easy, safe site to visit. It has links with Site 12 and Site 14 and forms part of an integrated network in the Preston/Coburg area that illustrate the recent geological history of Merri Creek and Edgars Creek.
References:	Schleiger, N.W, 1988, Coburg in Clark, I., Cook, B. & Cochrane, G.C. (eds.) Victorian Geology Excursion Guide, Aust. Acad. Sci., Canberra

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