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A New MINERAL SYSTEM Model for Broken Hill

• PGE-Ni- Au-Cu likely transported by upwelling plume-generated alkaline

magmas originating from the core-mantle boundary at 820 Ma during

break up of Rodinia.

• The core-mantle boundary zone is enriched in this assemblage of metals

that are anomalously concentrated in the Broken Hill district

• An alkaline model may also explain the metal endowment for zinc-lead-

silver: Plimer 1985 “The Broken Hill orebody has the gross composition of

a carbonatite”.

• The model has geodynamic support as the fragmentation and dispersal of

the supercontinent Columbia also occurred at ~1600 to ~1650 Ma, the
inferred age of the Broken Hill mineral system

• Understanding the mineral system clearly has important implications for

exploration in the district
KDC 2
22 Impact Minerals – Investor Presentation