DR. WYATT BAIN
Post-doctoral Fellow, Lakehead University
Kiruna-type iron oxide-apatite (IOA) deposits are an enigmatic class of magnetite-rich systems with a wide range of proposed genetic models. Here I present the results of three studies which examine inclusions in ore-stage apatite, diopside, and magnetite from characteristic IOA systems. These studies show that IOA mineralization in all three systems is associated with unusual Fe-rich, carbonate-sulfate melts which show remarkable consistency in terms of their compositions and microthermometric behavior. Moreover, carbon (δ13C) and oxygen (δ18O) isotope data indicates that these melts were formed via the anatexis and/or assimilation of local evaporite-bearing sedimentary rock by mafic-intermediate magmas in these systems. This interpretation is supported by the common occurrence of mafic-intermediate intrusive rocks crosscutting and assimilating evaporite-bearing carbonate strata in many notable IOA localities. These results indicate that a previously unrecognized genetic process involving crustal anataxis is involved in the formation of IOA mineralization and perhaps also promotes the formation of other Fe-, Ti-, and REE-rich systems.
THURSDAY, APRIL 15, 2021
10:00 AM Zoom Event