Abstract
Massive sulfide deposits represent a paramount source of base metals (Cu, Zn, Pb) and critical trace elements, yet their genesis within ancient tectonic settings remains enigmatic. This study focuses on the Paleoproterozoic Li’eryu volcanic belt—characterized by well-preserved volcanic edifices (including multiple volcanic centers)—within the Jiao-Liao-Ji orogenic belt, Eastern North China Craton, to address this knowledge gap. We conducted a detailed structural analysis of the Li’eryu Formation, integrated with in situ pyrite sulfur isotope (δ34S) and trace element analysis, magnetite trace element analysis, pyrite mapping, and zircon UPb geochronology of the host volcanic rocks. Our integrated results demonstrate a submarine hydrothermal origin for the mineralization: sulfur was predominantly derived from seawater sulfate (δ34S: +7.69‰ to +16.39‰), and the ore minerals precipitated from hydrothermal fluids in a volcanic setting at ~2.18 Ga, as evidenced by diagnostic trace-element signatures (e.g., Co/Ni in pyrite, VTi in magnetite) and complex zoning in pyrite reflecting multi-stage growth. Combined with regional geology, we classify the deposit as a volcanogenic massive sulfide (VMS) type formed in an extensional oceanic basin. This Paleoproterozoic tectonic setting, analogous to modern subduction systems, confirms the operation of plate tectonics at ~2.2 Ga. These findings not only elucidate the temporal and tectonic evolution of the Li’eryu belt but also provide a robust model for VMS genesis in ancient extensional oceanic basins worldwide.