Deep structure and metallogenic model of the Zhaishang super-large gold deposit in the West Qinling Metallogenic Belt revealed by a 3-D Magnetotelluric study

The genesis of the world-class Zhaishang gold deposit in the West Qinling Metallogenic Belt has been debated due to its distal location (>26 km) from potential magmatic sources. This controversy stems largely from the lack of deep structural constraints. To resolve this, we conducted a high-resolution 3-D Magnetotelluric (MT) survey. Our model reveals a conductive channel (C1) connecting the deposit to the distal Jiaochangba pluton, illustrating a primary pathway for the ore-forming fluids. No significant concealed pluton exists beneath Zhaishang; instead, mineralization is hosted within the ancient crystalline basement, which served as both a gold source and a permeability barrier focusing fluids into traps. The data further reveal crustal decoupling at ∼ 25 km depth, explaining the preservation of Mesozoic ore-forming features. We propose a distal magmatic-hydrothermal model in which these mixed fluids ascend through pre-existing structures, without a local magma chamber. This study provides new constraints on gold deposits in the West Qinling Belt by demonstrating that world-class mineralization can result from structural focusing of distal magmatic fluids.