Abstract:In order to study the trace element characteristics of rutiles in the Heihe region and the geological conditions for the mineralization of eclogite-type rutile deposits, this study selected rutiles from eclogite and garnet phengite schist in the Heihe region of Yunnan for LA-ICP-MS trace element analysis. The results show that the trace elements in rutiles exhibit a stepped three-level distribution pattern, with Nb and Ta being the most abundant, followed by Zr and Hf. The elements with lower content include Ba, Rb, Sr, Th, and REE. The protoliths of the eclogites and amphibole eclogite type belong to metamorphic mafic rocks, while the protoliths of kyanite-bearing amphibole eclogite and garnet phengite schist belong to basaltic tuffs and argillaceous rocks, respectively. The Nb/Ta ratios of rutiles in eclogite are higher than that of the entire rocks. The Nb and Ta contents of rutiles are related to the partition coefficients of elements among various minerals during metamorphism. The formation temperature of rutiles from the peak metamorphic stage of eclogites in the Heihe area was 578~605 ℃, obtained by using a Zr-in-rutile thermometer. The retrograde mass flow after the peak metamorphic process resulted in a reequilibrium of Zr in the rutiles. In addition, the Heihe region possesses the ore-forming material source, physical and chemical conditions for mineralization, and material basis for the formation of eclogite-type rutile deposits, which has certain prospecting potential.
