Metallogenic model of sandstone-hosted copper deposits: a case study from the Paleogene in Jiashi area, northwestern China

Abstract

Sandstone-hosted copper deposits, a type of Sediment-Hosted Stratiform Copper (SSC) deposits, are widely distributed globally. While economically viable deposits of SSC are relatively scarce, they account for approximately 30 % of the world's total discovered copper resources. However, there is still a lack of comprehensive and in-depth research into the depositional and metallogenic models of these deposits. The Jiashi area of the Tarim Basin in northwestern China, known for its economically significant Paleogene SSC deposit, lacks in-depth studies on metallogenic processes. To address this, field profile observations were conducted to analyze the sedimentary evolution, sequence stratigraphy, and tectonism of the Paleogene strata in the Jiashi area. Combined with elemental geochemical analysis of samples, the provenance of sediment, and the source of metallogenic materials, a robust metallogenic model was established. The results reveal the influence of provenance for the origin of Paleogene copper-rich strata. Sedimentary evolution played a crucial role in controlling the distribution of copper and sulfur elements, as well as the spatial arrangement of metallogenic beds. Additionally, nappe movement potentially generated faults, allowing upward movement of basin fluids, which played a crucial role in the formation of copper deposits within sandstone-hosted systems. Thus, this study offers a comprehensive analysis of the metallogenic processes involved in sandstone-hosted copper deposits, thereby contributing significant insights to the broader research on SSC deposits worldwide.