China Geological Survey

• Establishes the first precise mineralization age (230–240 Ma, Middle Triassic) for the Juyuan tungsten deposit using multi-method geochronology (in-situ zircon and wolframite/scheelite U-Pb, and muscovite Ar-Ar dating). • Identifies a coeval, highly fractionated I-type granite (242.0 ± 1.2 Ma) as the metallogenic source, formed in a post-orogenic intraplate extensional setting. • Extends the East Tianshan Triassic tungsten belt eastward, revealing significant quartz vein-type tungsten potential in the western Beishan orogenic belt. The Beishan Orogenic Belt, situated on the southern margin of the Central Asian Orogenic Belt, represents a significant endogenous metallic mineral resource base in northwestern China. Previous studies have indicated that tungsten mineralization in the Beishan Orogenic Belt primarily occurred from the Early Silurian to Middle Carboniferous. However, whether quartz vein-type tungsten mineralization developed during the Middle Triassic remains controversial. This study focuses on the newly discovered Juyuan tungsten deposit in the western segment of the Beishan Orogenic Belt. We investigated the geological characteristics, tectonic setting, and timing of magmatism and mineralization, establish a metallogenic model for the Juyuan deposit, and compare it with typical regional tungsten deposits to provide guidance for future mineral exploration through systematic fieldwork, geochemical analyses, and isotopic geochronology, and show that the zircon U-Pb age of the monzogranite in the mining area is 242.0 ± 1.2 Ma. The granite exhibits high SiO 2 , high alkalinity, high Al 2 O 3 , and low CaO characteristics, identifying it as a highly fractionated I-type granite formed in a post-orogenic intraplate extensional setting. The 40 Ar- 39 Ar plateau age of muscovite from the ore-bearing quartz veins is 239.97 ± 0.98 Ma, while the insitu U-Pb ages of wolframite and scheelite are 232 ± 14 Ma and 236 ± 24 Ma, respectively, collectively constraining the mineralization age to between 230 and 240 Ma. This study demonstrates that the Juyuan tungsten deposit is a quartz vein-type tungsten deposit closely related to magmatic-hydrothermal processes. The East Tianshan Triassic tungsten metallogenic belt can be extended eastward into the Beishan Orogenic Belt, indicating significant potential for exploring quartz vein-type tungsten deposits in an intraplate extensional setting in its western segment.