Geology of the Mt. Chambers Gorge region, South Australia.

Abstract

Mapping and section measuring south of Mt. Chambers Gorge has detailed 2,900 feet of Lower Cambrian carbonates, ranging from the massive carbonates of the Wilkawillina Limestone to the purple shales of the Billy Creek Formation. Carbonates include thinly laminated, oolitic and pelletal limestones and previously unreported mega-breccias. An autochthonous sedimentary pattern, typical of deposition in epeiric seas has been imprinted on the vertical sequence by a marine regression. This tends to be masked by allochthonous sediments, dominantly silts, clay and a coarse quartz sand, possibly eroded from diapers. Brecciolas (slumps) with archaeocyathid limestone megaclasts (to 70ft.) occur locally in the upper beds of the Parara Formation and may help to date diapiric movements. Late phase dole rites intrude diapers and cut related faults; mineralization is also diaper associated and includes copper and lead sulphides.