The Massive Australian Precambrian/Cambrian Impact Structure also known as MAPCIS is a proposed impact structure based upon arguments presented by Daniel P. Connelly at Geological Society of America meetings. Its center is located approximately equidistant between Uluru (Ayers Rock) and Mount Conner in Australias' Northern Territory. A hypothetical outermost ring is 2,000 kilometres (1,200 mi) in diameter is claimed to be the result of undefined far field stresses. The crater itself is smaller at approximately 600 km (370 mi) in diameter. Connelly argues that the age of this hypothetical impact is approximately 545 mya which puts it near the end of the Neoproterozoic Era.^[2] If confirmed as an impact crater, it would be the largest on earth.^[1]

• http://en.wikipedia.org/wiki/Massive Australian Precambrian/Cambrian Impact Structure