Neoproterozoic magmatic rocks associated with the opening of Paleo-Asian Ocean in Beishan area

Objective Precambrian rocks distributed in the Beishan area, located in the southern Central Asian Orogenic Belt, is significant for the study of the formation of the Paleo−Asian Ocean (PAO) and its associated mineralization. However, there are no constraints on the magmatism related to opening of PAO, and there is a lack of accurate chronological data regarding the formation of the Hongshan Iron Ore (HIO) deposits in the Beishan area.

Methods We present the results of field investigations, zircon U−Pb dating, and geochemical analyses of the gabbro and andesitic tuff found in the central Beishan area.

Results The new U−Pb dating results reveal the crystallization ages of the gabbro and andesitic tuff crystallized at 765 Ma, 756 Ma, respectively. The geochemical composition of the gabbro is indicative of an intraplate rift setting, suggesting a continental tectonic environment during its formation.

Conclusions Integrating our findings with previous studies, we infer that the southern PAO had opened before 765 Ma in the Beishan area. Additionally, we conclude that the HIO formation occurred during the Nanhuanian Period (756 Ma).