Xuyang Meng - Magmatic controls on porphyry Cu ± Au deposit formation, their rarity in the Archean

Xuyang Meng, Ph.D. candidate
Mineral Exploration Research Centre, Harquail School of Earth Sciences
Laurentian University, Sudbury, Canada

Conclusions
1 - The Côté Gold and Croxall (associated with Clifford stock) deposits formed from mildly (~ΔFMQ +0.6–0.7) to moderately (~ΔFMQ +1.5) oxidized magmas where voluminous early sulfide saturation was probably limited.
2 - The St-Jude deposit represents a rare case where ingress of externally derived heated seawater might facilitate metal fertility in a relatively reduced magma chamber (~ΔFMQ +0).
3 - We conclude that variable modes of formation for these deposits.
4 - The apparent rarity of porphyry-type Cu ± Au deposits in the Archean may be attributed to either local restriction of favorable metallogenic conditions and/or preservation or an exploration bias.