Geology
Red Rocks was formed about 200 million years ago during underwater volcanic eruptions. The raised shore platform with its pillow lava is noteworthy, being well preserved and very accessible. The purple coloured pillow lava erupted onto the sea floor and instantly cooled. The red colour is caused by finely dispersed iron oxide (haematite). The green colour is caused by the clay mineral, chlorite. Red and white banded rocks contain silica. Eventually all of these rocks were compressed, tilted, uplifted and eroded to form the exposures we see today. On both sides of Red Rocks greywacke sandstone and argillite siltstone are found. The City Council bought and closed the 80-year-old quarry in 2000. It has since been recontoured and is progressively being planted with appropriate native species.
