PhD topic: An examination of carbonate alteration zones in the Southern Alps, New Zealand, with the goal of understanding the fluid-rock interaction and assessing the potential link between gold mineralisation and lamprophyre magmatism
New Zealand’s Southern Alps possess a variety of carbonate-bearing alteration zones, some of which are associated with gold-mineralised faults (Craw et al., 2006) and others associated with lamprophyric magmatism (Cooper et al., 1986). Similar gold-lamprophyre associations are recognised in other parts of the world (e.g. Ashley et al., 1994). The goal of my research is to examine the different types of carbonate-bearing alteration in Mt. Aspiring National Park and assess the chemical similarities and differences during formation. Important aims are to assess whether the lamprophyric magmatism is genetically related to gold mineralisation, and to generate a model that explains the fluid-rock interaction.
Being an actively rising mountain belt, the Southern Alps are an excellent location to conduct this research as they show a variety of different crustal levels. Therefore the carbonate alteration zones show a variety of textural settings, have not been overprinted during subsequent deformation, and apart from the lamprophyres, magmatites, that could complicate matters (see Groves et al., 2003), are not present (Craw et al., 2006). Craw et al. (2006) suggested that there might be a link between the different alteration types, as they have similar ages and structural orientations. However, this inference now requires a comprehensive textural, geochemical, isotopic and thermodynamic evaluation.
- Ashley, P.M., et al. (1994). Lithos. 32. 249-272.
- Cooper, A. F. (1986) In: Smith (editor) (1986) Late Cenozoic Volcanism in NZ. Royal Society of NZ. Bulletin. 23. 313-336.
- Craw, D., et al. (2006) Mineralum Deposita. 41. 645-659.
- Groves, D.I., Goldfarb, R.J., Robert, F. & Hart, C.J.R. (2003) Econ. Geol. 98.1–29.