YY4 - You Yangs - Big Rock

This information has been developed from this publication:

Sites of Geological and Geomorphological Significance in the Western Region of Melbourne (1986) 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 for details of geological heritage reports, and a bibliography.

Location:	You Yangs - 726957. Shire of Corio. Western slopes of the You Yangs, 1 km south-west of Flinders Peak.	Sites - YY 3 - 5
Access:	Big Rock Road from Great Circle Drive, You Yangs Forest Park.
Ownership:	Crown land.
Site Description:	Big Rock is a broad outcrop of You Yangs Granite bounded by vertical and horizontal joints rather than the curving sheeting joints that are predominant in most of the Flinders Peak area. The flattened top is a ground level weathering platform formed as flaking and disintegration caused the retreat of more fractured overlying granite. The surface has a number of circular to elliptical pits or weathering holes 20 cm deep and up to 1 m in diameter. The high western face of the outcrop is a steep joint-bound slope with fractures too widely spaced to allow development of a boulder field.
Significance:	Regional. Big Rock differs from other outcrops in the You Yangs due to joint type and spacing. It is the largest broad platform in the area and contains the best examples of weathering pits.
Management:	Class 2. The granite surface is robust and the area should be maintained as a public access and lookout point. Structures to assist visitors eg - guide rails or safety fences, if considered necessary by the managing authority, should be located so as not to interfere with the catchments of the small weathering pits on the surface of Big Rock.

Page top