Timing of carbonatite-hosted U-polymetallic mineralization in the
supergiant Huayangchuan deposit, Qinling Orogen: Constraints from
titanite U–Pb and molybdenite Re–Os dating
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Abstract
The newly-discovered supergiant Huayangchuan uranium (U)-polymetallic (Sr, Se, REEs, Ba, Nb and Pb) deposit
is located in the Qinling Orogen, central China. The deposit underwent multistage mineralization, with the main
carbonatite ore stage being the most important for the U, Nb, REE, Sr and Ba endowments. According to the
mineral assemblages, the main carbonatite ore stage can be divided into three substages, i.e., sulfate (Ba–Sr),
alkali-rich U and REE-U mineralization.
Main-stage titanite from the Huayangchuan igneous carbonatite are rich in high field strength elements (HFSEs,
e.g., Zr, Nb and REEs), and show clear elemental substitutions (e.g., Ti vs. Nb þ Fe þ Al and Ca þ Ti vs. Fe þ Al þ
REE). High-precision LA-ICP-MS titanite dating yielded a U–Pb age of 209.0 2.9 Ma, which represents the mainstage
mineralization age at Huayangchuan, and is coeval with the local carbonatite dyke intrusion. This mineralization
age is further constrained by the Re–Os dating of molybdenite from the Huayangchuan carbonatite,
which yielded a weighted mean age of 196.8 2.4 Ma. Molybdenite Re contents (337.55–392.75 ppm) and C-OSr-
Nd-Pb isotopic evidence of the Huayangchuan carbonatite both suggest a mantle origin for the carbonatite. Our
study supports that the Late Triassic carbonatite magmatism was responsible for the world-class U-Mo-REE
mineralization in the Qinling Orogen, and that the regional magmatism and ore formation was likely caused by
the closure of the Mianlue ocean and the subsequent North China-South China continent-continent collision.
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