The Indicative Significance of Interlayer-Sliding Fault Deformation in a Thrust–Fold Structure of the Huize Mine District to the Variation of Ore-Hosting Space: Insights from Analogue Modeling

Abstract

Interlayer-sliding faults play a crucial role in governing the distribution of metal deposits. Nevertheless, the mechanism by which these faults control the spatial arrangement of ore bodies throughout the evolution of fault–fold structures remains unclear. Here, we formulated three series of experimental models to explore variations in deformation and alterations in the mechanical characteristics of interlayer-sliding faults throughout the evolution of the thrust–fold structures. The experimental results indicate that the thrust faults formed in the three series of experiments all propagate in a piggyback propagation, displaying an imbricate thrust in cross-sections. Compared with Model 1 and Model 2, Model 3 demonstrates the longest transmission distance of the deformation front, the smallest thrust wedge taper angle, the fewest thrust faults with the largest spacing, and a reduction in the dip angle of the thrust fault. Particle image velocimetry (PIV) showed that in the top view, the position of minimum horizontal strain in each stage is the position of thrust faults. In the cross-sectional view, the development location of thrust faults shows the low-value area of the velocity field and surface strain field, and the development location of the interlayer-sliding fault and tensile space in the core of the fold displays the high-value area of velocity field and surface strain field. The structural characteristics of experiment 3 are highly similar to the actual geological model, indicating that there is a certain ore-hosting space in the Dengying Formation deep in the deposit. Although the expansion zone in the deep area is smaller than that in the shallow area, it still has favorable prospecting prospects.

Keywords

• thrust–fold structures
• interlayer-sliding fault
• analogue modeling
• particle image velocimetry (PIV)
• Huize Zn–Pb–(Ge–Ag) mine district