DARWIN DAM
Location: 26km south of Queenstown along Mt Jukes Road | Google Maps Reference
Key facts about this geosite:
• Varied geology including the Late Cambrian Owen Conglomerate, Ordovician Gordon Limestone, partly concealed by Pleistocene glacial deposits and Silurian Eldon Group sandstones
• Darwin Crater, which formed from a meteorite impact 816,000 years ago is to the south of this site
Geosite Description: Lake Burbury is an artificial lake that flooded the old mining town of Crotty, when the Crotty Dam on the King River was constructed by Hydro Tasmania ) in 1991. The Darwin Dam is a secondary structure to prevent the lake waters from spilling over a low watershed into the Andrew River, a tributary of the Franklin River.
The geology of the region is shown on the geological map. The ridge to the west of the dam has formed the from resistant Late Cambrian Owen Conglomerate. Just west of the dam, a pair of north-south trending faults are roughly parallel to the shore of the lake, which have downthrown the rock sequence to the east. A sliver of Ordovician Gordon Limestone, partly concealed by Pleistocene glacial deposits, lies between the faults, whereas Silurian Eldon Group sandstones and siltstones form the eastern (far) abutment of the dam. On a clear day, take in the view to the north towards Mt Owen.
