Recognised as a significant geological feature in South Australia, Gun Emplacement refers to the flat treeless plateau in the southwestern area of Anstey Hill Recreation Park. Its unique name was given by war veteran Major Edmunds.
It is believed that this million-year-old weathering on the land surface was developed upon sand, which filled in a fault angle depression and later eroded to some extent. An ironstone capping of several metres' thick then formed on the exposed sand, resisting further erosion.
The remnant of this ancient weathering can still be seen today along the Geological Hike trail. The trail, starting at Gate 9 on Lower North East Road, also offers fantastic views of Adelaide as well as a former quarry operated by the Klopper family in the late 1800s. Amazingly, this quarry became a staging venue for the Festival of Arts first in 1980 and then again in 1988.