On 14 June Professor David Philips, Head of the School of Earth Sciences at University of Melbourne, came to the Macedon Ranges to talk about the geology of Hanging Rock. His visit included a walking tour of some of the Rock’s geological features, and a presentation back at the Hut entitled Hanging Rock – A Journey in Space and Time.
Hanging Rock is the eroded remnants of an extinct volcano about 6.2 million years old. Known as a mamelon, it was created as stiff magma oozed through a vent in the bedrock, and congealed in place, forming a small hill or mound on the surface. The outflow from successive eruptions forms additional layers on top. In Hanging Rock’s case, the resulting pile of layers stands over 100 metres above the plain. Erosion then removes flanks of volcano from around the plug, which has led to the appearance of Hanging Rock as we know it today.
We also heard about the other two mamelons nearby, created in the same period: Camels Hump, to the south on Mount Macedon and, to the east, Crozier’s Rocks.
With 29 keen attendees, this has been one of our biggest events since our incorporation. Thanks to everyone who joined us on this sunny winter day, and many thanks to Professor Philips for a fascinating presentation and tour.