Structural controls on iron mineralization in the Shizan region, northwest of the Sangan mine, northeast of Iran

Abstract

The structural system related to iron mineralization in the form of skarn and hydrothermal deposits in the Shizan region, northeastern Iran, has a direct relationship with the geometry of deformations, fractures, faults, and intrusive masses, with their penetrative nature serving as the source of fluid motion. This study aims to investigate tectonic structures, analyze them, identify stress trends and mineralization phases, and illustrate the region's structure. A tectonic model related to mineralization in the Shizan region, situated at the eastern end of the intracontinental Doruneh fault, will be presented. Tectonic events in the area are attributed to the activity of this fault, with a particular focus on the Illeh fault. This fault is an important branch that influences mineralization and morphology. By surveying the faults in the region and analyzing the density of each fault series and mineral trends, two main stress trends were identified: one trending NW-SE and the other NE-SW. The change in stress trends has led to the formation of three generations of faults and mineralization. The first mineralization phase, characterized by the N080-120 trend, occurred within the first stress trend along E-W to NW-SE faults. The subsequent mineralization phase with the N350-070 trend was associated with the second stress trend along N-S to NE-SW faults. Following the N015-060 trend, the final mineralization phase occurred when the second stress trend was reactivated along NE-SW faults. The structural evolution during the initial phase of the stress trend resulted in the formation of horsts, grabens, and half-grabens. The results indicate a clear correlation between the open spaces formed in the fault zones and mineralization, facilitating solution flow and promoting iron precipitation in the first and second phases. © 2025