Minchinbury Sandstone is a component of the Wianammatta Group of sedimentary rocks in the Sydney Basin of eastern Australia.
[1] Formed in the middle Triassic period, this sandstone was structured by marine deposition as a set of sandy barrier islands at a coastal shoreline.
Outcroppings are weak and not easily found, but it may be seen in places like road cuttings in localities from Epping, Grose Vale-Kurrajong, Kellyville, Rogans Hill, Bankstown, Pendle Hill, Bonnyrigg, Menangle, Duck River, Brownlow Hill and other sites.
It comprises up to 70% quartz with calcite and volcanic lithic fragments.
Related to Greywacke, it comprises fine to medium-grained lithic sandstone.