Lake George is an Endorheic lake, as it has no outflow of water to rivers and oceans.
The lake is believed to be more than a million years old. Originally, small streams drained its catchment into the Yass River, but then the Lake George Escarpment rose due to major crustal movement along a strong fault line, blocking this drainage and forming the lake. Lake George has in previous Ice Ages been much larger and deeper.[citation needed]
The thickness of sediment beneath the lake exceeds 250 metres (820 ft), according to a Bureau of Mineral Resources Canberra drilling programme in the 1982/83 summer. The oldest sediments, which lie some distance above the bedrock, were dated at 3－5 million years using spore and pollen analysis and magnetic reversal stratigraphy.[citation needed]
At 25 km (16 mi) long and 10 km (6.2 mi) wide, Lake George is long, largely flat and extremely shallow, with a very small catchment. Resultant evaporation rates as well as a tendency for strong winds to blow the water back on itself ex
