Geology and Geomorphology of Jenolan Caves and the Surrounding Region DAVID F. BRANAGAN1, JOHN PICKETT2 AND IAN G. PERCIVAL3 1Honorary Associate, School of Geosciences, University of Sydney, NSW 2006 (
[email protected]); 2Honorary Associate, Geological Survey of NSW, WB Clarke Geoscience Centre, Londonderry NSW 2753 (
[email protected]); 3Geological Survey of NSW, WB Clarke Geoscience Centre, Londonderry NSW 2753 (
[email protected]) Published on 30 May 2014 at http://escholarship.library.usyd.edu.au/journals/index.php/LIN Branagan, D.F., Pickett, J.W. and Percival, I.G. (2014). Geology and Geomorphology of Jenolan Caves and the Surrounding Region. Proceedings of the Linnean Society of New South Wales 136, 99-130. Detailed mapping by university students and staff since the 1980s has significantly elucidated previously poorly known stratigraphic and structural relationships in the Jenolan Caves region. Apart from andesite of ?Ordovician age, rocks west of the caves probably correlate with the lower Silurian Campbells Group. That succession is faulted against the Silurian (mid Wenlockian) Jenolan Caves Limestone, in which caves developed during several episodes from the late Palaeozoic. Immediately east of Jenolan Caves, siliciclastic sedimentary and volcaniclastic rocks with interbedded silicic lavas constitute the newly defined Inspiration Point Formation, correlated with the upper Silurian to Lower Devonian Mount Fairy Group. Several prominent marker units are recognised, including limestone previously correlated with the main Jenolan limestone belt. Extensive strike-slip and thrust faulting disrupts the sequence, but in general the entire Silurian succession youngs to the east, so that beds apparently steeply-dipping westerly are actually overturned.