Coupling of tectonic evolution and magmatic lithium mineralization: a case study of the Tugeman–Ayage orefield in the Altyn tagh, Northwest China

• Tugeman–Ayage mineral field primarily underwent four tectonic events (D1-D4) during the Neoproterozoic to Paleozoic (550–400 Ma), respectively. • The Tugeman and Ayage sections from south to north reveal differential uplift and erosion rates across the region, influenced by proximity to major Altyn Tagh faults. • The northern Tugeman–Ayage tectonic unit provides significant potential for deep exploration. • The northeastern Ayage region has excellent potential for concealed lithium deposits driven by dome-related structural and magmatic dynamics. The Tugeman–Ayage orefield, located in northwest China’s giant Altyn tagh metallogenic belt, consists of a significant concentration of lithium-beryllium-bearing pegmatites. As the earliest breakthrough of lithium ore prospecting in the Altyn area, its geological characteristics study is essential for establishing regional metallogenic regularity and prospecting practice. This study integrates regional structural analysis, low-temperature thermochronology, and spatial mineralization patterns to elucidate the coupling between tectonic evolution and magmatic lithium mineralization. Through systematic field outcrop observation and detailed structural analysis, we divide the tectonic deformation process of the Tugman-Ayage ore field into four stages (D1-D4) during the Neoproterozoic to Paleozoic, which are pre-collisional subduction (D1), continental collision (D2), post-collisional extension (D3), and post-mineralization modification (D4), respectively. During the D2 stage, due to the influence of collision orogeny between the North Altyn tagh block and Central Altyn tagh block, the region mainly developed the NW-SE direction compression, and the tectonic deformation style in this stage shaped the main structural framework of the Tugeman–Ayage region. At this stage, extensive fracture zones developed in the area, providing ideal space for the placement of the pegmatite, but there was no development of pegmatite. In the D3 stage, the regional left-lateral strike-slip extension and magmatic differentiation facilitated the emplacement of granitic pegmatites in favorable structural spaces, and mainly produced along the preexisting structural zone and fracture zone developed in the previous D2 stage. Spatial zoning of the pegmatite veins, transitioning from beryl-dominant (Be) in the inner zone to spodumene-rich (Li) in the outer zone, indicates a concealed mineralizing intrusion associated with a magmatic dome. Low-temperature thermochronology tests along the Tugeman and Ayage sections from south to north reveal differential uplift and erosion rates across the region, influenced by proximity to major Altyn tagh faults. The northern Tugeman–Ayage tectonic unit, characterized by slight erosion, provides significant potential for deep exploration. In contrast, the moderate erosion in the central Tugeman–Ayage tectonic unit highlights optimal conditions for lithium prospecting. The Huanglongling discovery further validates the metallogenic potential of the central Tugeman–Ayage tectonic unit. This study underscores the critical role of tectonic and magmatic processes in controlling lithium mineralization and provides a robust framework for exploration in the Altyn tagh metallogenic belt. The insight from the Ayage-Tugeman orefied suggests that the northeastern Ayage region has excellent potential for concealed lithium deposits driven by dome-related structural and magmatic dynamics.