REE-bearing Cambrian-Ordovician episyenites and carbonatites in southern and central New Mexico, USA

Dr. Virginia McLemore, Principal Senior Economic Geologist with the New Mexico Bureau of Geology and Mineral Resources, presenting to the Arizona Geological Society on 7 Sept. 2023. Her talk is about rare earth element (REE)-bearing Cambrian-Ordovician episyenites and carbonatites in southern and central New Mexico, USA. A widespread Cambrian-Ordovician alkaline magmatic event occurred throughout New Mexico and southern Colorado (McMillan and McLemore, 2001) and is evidenced by the intrusion of carbonatites, syenites, monzonites, and alkaline granites and associated K-metasomatism (i.e. fenites and episyenites). Episyenites found in the Caballo, Burro, and Zuni Mountains are brick-red, K-feldspar-rich rocks formed by desilicification and metasomatism of granites by alkali-rich fluids, possibly related to alkaline or carbonatite magmas. The episyenites were originally interpreted to be igneous, but based on recent mapping and geochemical analysis, are actually metasomatic in origin.

[@peggieincolfaxca3818]

fascinating!! (not a geologist, but I learned a lot!)

[@azgsweb]

I am very glad you enjoyed the talk, it sounds like you are a geologist at heart! ⛏