Structural-morphological and REE geochemical control of the correctness of Sm-Nd dating for fluorite formation in the garsonui deposit,eastern Transbaikalia

Using ICP-MS, X-ray excited optical luminescence (XEOL), and Sm-Nd isotopic analysis, the distribution, structural position, and isotopic characteristics of isomorphic REE admixtures were studied in ten fluorite samples with different colors, morphologies, and cleavage characteristics from the Garsonui epithermal deposit. It was shown that the comprehensive analysis of the structural-morphological and REE geochemical features of samples can be used for the optimization of sample selection for correct Sm-Nd dating. As a result, the Sm-Nd method was used for the first time to constrain the age of the main stage of the formation of the Garsonui deposit, which is one of the largest fluorite deposits in Transbaikalia, as 141 ± 6 Ma.