Rutile compositions at the Big Bell Au deposit as a guide for exploration

Abstract

The compositions of 277 grains of rutile from 24 samples from the Big Bell Au deposit and nearby smaller deposits, in the Murchison Province of Western Australia, reveal that rutiles associated with ore at Big Bell, and for up to 200 m into the footwall rocks, are V+Fe+W+Sb-rich - a characteristic of rutile that has previously only ever been documented at the Hemlo Au deposit in Canada. Rutile from the nearby Fender and Indicator deposits share this Big Bell-type signature, but that from North Fender contains Nb ± Ta, with W and Fe, suggesting formation from a quite different fluid and at a different period. The preservation of the different types of rutile in regolith samples in the Big Bell region indicates that it is possible to discriminate between the V+Fe+W+Sb-rich and Fe+Nb ± Ta-rich alteration in rutile using regolith samples. Show more