Abstract
Hematite-bearing biotite/sericite gold deposits and epidote skarns in greenstones of the 2.7 Ga Eastern Goldfields Superterrane are associated with monzo-diorite-tonalite and monzonite-syenite intrusions. Older thrust and strike-slip faults were reactivated and mineralised during late-orogenic magmatic activity. At Granny Smith (37 t Au) in the Laverton district, a monzodiorite stock (2665±3 Ma) cuts across D1 folds and D1 thrusts in greywacke. Biotite-sericite lodes formed at 2660±5 Ma when renewed reverse faulting (D3) fractured the stock. At the nearby Wallaby deposit (180 t Au), monzonite-syenite dykes intruded a 600m-wide pipe of conglomerate-hosted epidote Fe skarn (2662±3 Ma). Intrusion-related Au-Ag veins cut the skarn at dike contacts. Reverse faults (D3) cut the skarn and veins and contain sericite lodes dated at 2650±6 Ma. Deposits in the Kalgoorlie district are controlled by strike-slip faults. The Golden Mile (1500 t Au) comprises D2 sinistral shear zones and minor D3 thrusts displacing D1 folds in meta-dolerite. Porphyry emplacement and sericitic alteration occurred during the transition from D2 to D3. At Mt Charlotte (125 t Au), D3 thrusts are offset by D4 dextral strike-slip faults controlling quartz-veined ore (2655±13 Ma) in meta-dolerite. Epidote Fe-Cu-Au skarns and associated sericite Cu-Au lodes occur at Mt Shea near Kalgoorlie, where D3 thrusts displace monzodiorites (2658±3 Ma) of an unroofed intrusive complex.
| Original language | English |
|---|---|
| Title of host publication | Smart science for exploration and mining |
| Subtitle of host publication | Proceedings of the 10th Biennial SGA Meeting, 2009, Townsville, Australia |
| Place of Publication | Australia |
| Publisher | Society for Geology Applied to Mineral Deposits |
| Pages | 954-956 |
| Number of pages | 3 |
| Volume | 2 |
| ISBN (Print) | ISBN 978-09-8055-868-5 |
| Publication status | Published - 2009 |