Late Jurassic gold mineralization in the North China Craton’s Western belt: S-Pb-H-O isotopic and apatite U-Pb geochronology insights from the Luyuangou gold deposit

Abstract

The North China Craton (NCC) is known for its abundant gold deposits, which occur across two gold metallogenic belts: the western and eastern belts, both trending NNE. Unlike the eastern metallogenic belt, which experienced short-timing early Cretaceous gold mineralization, the western metallogenic belt predominantly features late Jurassic mineralization. However, gold deposits from the late Jurassic are predominantly found in the northern part of the western belt, with fewer occurrences in the southern segment, specifically in the Xiaoqinling-Xiong’ershan gold region. This discrepancy has led to limited research on the late Jurassic gold mineralization in the southern segment, with ongoing debate regarding its occurrence. The Luyuangou gold deposit is a key example in the Xiong’ershan gold district (XESGD), which has long been regarded as a product of early Cretaceous activity due to previous dating accuracy and limitations, thereby limiting the comprehension of its genesis and hindering prospecting endeavors. This paper introduces new geochronological and isotopic (S-Pb-H-O) data for the Luyuangou gold deposit. U-Pb dating of hydrothermal apatite associated with gold-bearing pyrite constrains the mineralization timing to 157.1 ± 6.6 Ma, which fits the Late Jurassic gold mineralization event. The S-Pb-H-O isotope data suggest that the ore-forming materials originated from both the crust and mantle, with ore-forming fluids derived from magmatic and meteoric waters. Collectively, the findings of our study support that the Luyuangou deposit formed in an extensional tectonic environment during Jurassic magmatic activity, which has implications for future prospecting directions in the XESGD.