25 Clifton Springs - Slump Amphitheatre

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

Sites of Geological and Geomorphological Significance in the Westernport Bay Catchment (1984) by Neville Rosengren.
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 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	878758 to 876756. The site begins at a long, deep gully 500 m north of the car park at the end of Beacon Point Road, and extends for 400 m north of the gully.	Site 25, Clifton Springs slump amphitheatre
Access	Beacon Point Road.
Ownership/Managing Authority	Crown land (Port of Geelong Authority) below high water mark; private land above high water mark.
Site Description	The site encloses a long, bowl-shaped landslip with a high, gullied headwall scarp of grey silty clays and fine sands. The complex is a major slump amphitheatre that has undergone more coastal recession than that to the north of McAdams lane, and as a consequence, the coastal outcrops are less well exposed. At the northeastern end there is a deep, active, branching erosion gully that is cutting back into the plateau behind the scarp. The shore platform at the western end of the site is a fault-bounded outcrop of a limestone member (Curlewis Limestone) of the Fyansford Formation.
Significance	Regional. The site is a clear example of a major backward rotational coastal landslip. The back tilting is less pronounced than at Site 21 and the outer (seaward) cliff is lower. It therefore has interest for field mapping and comparison on the forms and processes at the two sites. It also illustrates a process of cliff formation that is indirectly related to marine processes. The northern gully is the largest active gully on the Bellarine Peninsula and has only been recently generated or re-activated.
Management Considerations	Class 2. The site would be best left intact as a working model of post-landslip landform development. This activity poses no threat to existing structures although the headwall of the largest active gully could be treated to reduce the loss of the adjacent property. The site is probably geotechnically unsuitable for building development because of the landslip history and the erosional activity of the cliffs.
References	Ladd, P.G. (1971)

Image: Sites of Significance Port Phillip Bay

Site 25, Low seaward slope of slump
amphitheatre north of Clifton Springs

Site 25, Gully in headwall scarp of slump
amphitheatre north of Clifton Springs

Site 25, Clifton Springs slump amphitheatre

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