What group of large spherical granite boulders is found in the Northern Territory?

The group of large spherical granite boulders in Australia’s Northern Territory is known as the Devils Marbles.

The boulders form part of Karlu Karlu / Devils Marbles Conservation Reserve, about 105 kilometres south of Tennant Creek. They are exposed portions of a much larger granite formation. Geological weathering gradually rounded the blocks through exfoliation, chemical decay and repeated heating and cooling in the desert environment. Some boulders split cleanly, while others appear precariously balanced.

The English name comes from explorer John Ross, who reportedly described the area during the 1870 Australian Overland Telegraph Line expedition as the Devil’s country, with the Devil having emptied his bag of marbles. The Aboriginal name Karlu Karlu means “round boulders” and is associated with important cultural and spiritual traditions.

The site is not simply a collection of unusual rocks. Karlu Karlu is a registered sacred site with connections to Alyawarre, Kaytetye, Warumungu and Warlpiri peoples. Since 2008, traditional owners and the Northern Territory Parks Service have jointly managed the reserve.