Three-Dimensional Model of the Huangshanxi Ni-Cu Sulfide Deposit and Its Implications for Mineralization, EasternTianshan, NW China

A series of magmatic Ni-Cu sulfide deposits have been successively discovered in the Huangshan-Jingerquan mineralization belt in the eastern Tianshan, with nickel reserves exceeding 1 million tons, making it one of the most developed regions for magmatic Ni-Cu sulfide deposits in the orogenic belt. The Huangshanxi deposit is a large magmatic Ni-Cu sulfide deposit in this region, formed during the transition from collisional orogeny to a post-collision extensional environment. Regional ductile shear zones and fault structures controlled the emplacement of the Ni-Cu sulfide-bearing mafic-ultramafic intrusions. The faults acted as conduits for magma emplacement and provided spaces for sulfide segregation and accumulation. Based on geological data, including drill cores, exploration section maps, and mid-section geological maps, this study constructed a 3D geological model of the Huangshanxi deposit using Surpac software. By analyzing the three-dimensional space of the orebodies, mafic-ultramafic intrusive rocks, and structures, as well as the spatial distribution of Ni and petrographic characteristics of sulfide ores, the role of structure in the formation of Ni-Cu mineralization has been discussed. The main conclusions are as follows:①The morphology of the Huangshanxi intrusion is significantly influenced by faults. The nearly east-northeast-oriented F1 and F10 reverse faults are the most significant faults in the area and control the morphology of mafic-ultramafic rocks.Leading to a unique "tadpole-shaped" intrusion morphology and a basin-like cross-sectional profile.②The orebody 32X was overprinted by post-mineralization structure.It was reactivated by tectonic superposition and enriched along the north-south fault. The ore alteration and deformation were apparent.In contrast, the orebody 30, while partially affected by structural processes leading to localized sulfide enrichment, shows limited deformation and weaker alteration. Mafic-ultramafic rocks primarily control the Ni-Cu mineralization after magmatic emplacement along structures.This study advances the understanding of the magmatic and mineralization processes of the Huangshanxi deposit. It provides new insights into the genesis of magmatic Ni-Cu sulfide deposits in the Northern Tianshan. It can serve as a reference for discussing the genesis and exploration of magmatic Ni-Cu sulfide deposits in the orogenic belt.