Mount Stromlo - Geology

Geology

The rock on Mount Stromlo consists of ignimbrite from the Laidlaw Volcanics. This erupted in the upper Silurian period over the top of the Deakin Volcanics rhyodacite which is visible on the surface on the lower slopes in the east and southeast sides. The northern lower slopes are covered with a calcareous shale which is included in the Laidlaw Volcanics as it was deposited at the same time. This is cut off on the northwest side by the Winslade Fault, which heads north east to Cook and Kaleen. A spur fault heads off east from the Winslade Fault to under the Scrivener Dam. On the other side (north west and north) of these faults are middle Silurian period rhyodacite volcanic deposits from the Walker Volcanics. The northern side was uplifted compared with the southern side.

See also: Geology of the Australian Capital Territory