West Pymble Bicentennial Park Walk

This short walk will be led by geologist John Martyn. John is author of the books Sydney’s Natural World, Field Guide to the Bushland of the Lane Cove Valley and Rocks and Trees, all published by STEP. He’s also co-ordinator and compiler of STEP’s published series of bushwalking maps.

The key geosite in Bicentennial Park is the basalt dyke in the old abandoned quarry face, one of a large number of igneous rock occurrences in the Ku-ring-gai GeoRegion and more accessible than most. It is an excellent example of the thermal effects of super-hot intruded basalt magma on Hawkesbury Sandstone, which has been visibly baked and recrystallised to a hard, white quartzite, once sought after and quarried for heavy duty tasks like road base and railway ballast. The Georegion team are currently liaising with Ku-ring-gai Council to produce a permanent information sign for the site, and to clean out the weed growth that partially obscures the heavily weathered dyke.

Meet at: Entrance to West Pymble Bicentennial Park via Bicentennial car park (entrance via Loftberg Road)

Cost: Free

Bring: Water, snack and wear good walking shoes