Geology and Mineral Deposits of the Broken Hill Block

The Broken Hill Block, which forms part of the late Paleoproterozoic Curnamona Craton in eastern Australia, hosts the largest Pb-Zn-Ag deposit in the world, the Broken Hill deposit, as well as deposits of various other types, including the Pyrite Hill cobalt deposit. 

In this field trip, these two deposits will be examined from a mineral systems perspective with field stops to highlight aspects of the regional stratigraphy and structure to give participants insights into the syn- and post-rift basin architecture, fluid pathways and potential heat and metal sources along with other aspects of the regional geology that may have controlled or influenced the distribution and location of ores. Many ore bodies are located along or close to a regionally significant redox boundary beneath where stratigraphy has been variably albitised and/or oxidised. The origins of this boundary and its relationship to mineralisation are just one of the many controversies to be had in the field.

Emphasis will be given to parts of the syn-rift Broken Hill Group (including the Hores and Potosi gneisses) that host the bulk of the mineral deposits as well as a many of the granite gneisses and amphibolites thought to have served as metal or heat sources.