Early Cretaceous W–Nb–Ta Mineralisation in the Southeastern Xingmeng Orogenic Belt, NE China: Geochronological Evidence From the Jiabusi Nb–Ta and Narewula W Deposits

Abstract

The Xianghuangqi region in the southeastern section of the Xingmeng Orogenic Belt (XMOB) has gained attention for its potential rare mineral yield, particularly from multiple W and Nb–Ta deposits. However, limited geochronological data limits our understanding of their origin and progress in W–Nb–Ta exploration. We thus performed ⁴⁰Ar/³⁹Ar muscovite and U–Pb wolframite, cassiterite and columbite dating on the Jiabusi Nb–Ta and Narenwula W deposits within the Xianghuangqi region. Our findings revealed that the ⁴⁰Ar/³⁹Ar plateau age of muscovite from the Jiabusi deposit (135.17 ± 1.34 Ma) aligns with that of the Narenwula W deposit (135.83 ± 1.43 Ma). This consistency is further supported by U–Pb dating of wolframite, cassiterite and columbite in Jiabusi, at 136.4 ± 2.0, 132.1 ± 3.1 and 136.0 ± 3.5 Ma, respectively. These data suggest that mineralisation of W–Nb–Ta in the Xianghuangqi area occurred during the Early Cretaceous, probably in association with the late-stage evolution of intrusions within the granite complex. Zircon U–Pb dating of Jiabusi albite granites yielded an age of 137.5 ± 1.2 Ma, indicating later formation than the Kusigui biotite granites, which date at approximately 149 Ma in the same region. The geochronological data highlight a regional Early Cretaceous event of W–Nb–Ta mineralisation around 135 Ma, influenced by tectonic interactions between the Mongolia–Okhotsk Ocean and the Paleo-Pacific Plate. We conclude that, most probably, W–Nb–Ta ore deposits of the southeastern segment of the XMOB in the Xianghuangqi area were emplaced during the Early Cretaceous.