Joaquin Ruiz Research includes radiogenic isotopes applied to the study of regional tectonics, origin of magmas, and hydrothermal ore deposits. There is a major research effort being carried out in the Department in understanding the metallogenesis of copper in the Andes. Presently the work has focused on ore deposits of Chile with Ph.D. candidate Ruben Padilla and Spence Titley studying La Escondida under the auspices of BHP, and postdoc Claire Freydier and Joaquin Ruiz working on the overall metallogenetic problem of copper mineralization with support from Phelps-Dodge, NSF and the Univ. of Chile in collaboration with Francisco Munizaga.
Chile is a major producer of copper, most of which occurs in base metal porphyry and manto deposits.
Interestingly, although the magmatism that is associated with the mineralization is associated with subduction, which is a continuous process, mineralization occurs at specific time intervals. The manto deposits are generally Mesozoic in age. This episodic mineralization, which we also described in Arizona, suggests that a process that may also include the crust is required for copper metallogenesis. A fundamental difference between mantos and porphyry copper deposits in Chile is the relative importance of intrusions spatially associated with the mineralization. The porphyry deposits are set within Mesozoic to Tertiary intrusive complexes where large hydrothermal systems with prolonged interaction between fluids in the intrusive magmas and country rocks concentrated metals well above average crustal values.