Ba-REE fluorcarbonate minerals froma carbonatite dyke at Bayan Obo,Inner Mongolia, North China

Abstract

Department of Geology, University of Leicester, United KingdomWith 3 FiguresReceived August 24, 1998;revised version accepted December 17, 1999SummaryThe new occurrence in a carbonatite dyke at Bayan Obo, Inner Mongolia, North China,of the Ba-REE fluorocarbonate minerals cebaite, hunghoite and cordylite is presented,together with their chemical composition, rare earth element (REE) patterns, andsyntaxial intergrowth relationships. These syntaxial textures, investigated by scanningand electron microprobe techniques, are interpreted in terms of the cooling historyduring the late-stage crystallization of the carbonatite magma or possible later events.The REE distribution patterns of the Ba-REE fluorocarbonate minerals in the dyke aresimilar to those of the corresponding minerals in the dolomite marble that hosts thegiant REE-Nb-Fe ore body at Bayan Obo, providing evidence that the two may becogenetic.ZusammenfassungBa-SEE Fluorkarbonat-Minerale aus einem Karbonatitgang bei Bayan Obo, InnereMongolei, Nord-ChinaDie Ba-SEE Fluorkarbonate Cebait, Huangoit und Cordylit kommen in einemKarbonatitgang bei Bayan Obo, Innere Mongolei, Nord-China, vor. Ihre chemischePresent address: School of Ocean and Earth Science, University of Southampton, UnitedKingdom