Apatite: A proxy to study ore deposits?

International audienceApatite (Ca5(PO4)3(OH, F, Cl)) is an ubiquitous accessorymineral found in many types of rocks and environments. Thismineral has several key features for the characterizationand/or the dating of fluid circulation or magmatismresponsible for the emplacement of mineralization:1. It often incorporates uranium during its crystallization.This makes it an excellent candidate for U-Pb dating.Moreover, apatite can also be dated by the fission tracks and(U-Th)/He methods. Therefore the same mineral can bringinformation on the age of the mineralization and itsexhumation history.2. Apatite is an excellent trap for the P, F, Cl, OH, butalso for Rare Earth Elements (REE) [1].3. This mineral can easily react in the presence of brines,or aqueous fluids containing CO2, HCl, H2SO4 and/or F [2].4. In many ore deposit, the crystallization of apatite iscontemporaneous with mineralization processes [3].5. Its closure temperature with respect to the U-Pb system(375-550°C) gives it a peculiar role for dating hydrothermalevents [4].Accordingly, apatite is, a priori, an excellent proxy forobtaining extensive information about mineralizing fluidsand/or fertile magmas (temperatures, compositions and agesor durations of the events), information that is essential forestablishing a metallogenic model.We will present a comprehensive set of CL imaging,EPMA analyses, SIMS stable isotopes and U-Pb dating onapatite from several ore deposits in order to assess thepotential of this mineral for the study of ore deposits.[1] O’Really & Griffin & (2000). Lithos, 53, 217-232. [2]Pan & Fleet (2002). Rev in Mineral and Geochem, 48, 13-49.[3] Nyström & Henriquez (1994). Econ. Geol. 89, 820–839.[4] Blackburn et al. (2011). Contrib. Miner. Petrol. 162, 479–500