Morphology, morphometry, structural controls, and geomorphic evolution of scoria cones in the Uran–Togoo volcanic area, central Mongolia: implications for monogenetic volcanic fields

The Uran–Togoo volcanic area in central Mongolia preserves well-developed monogenetic volcanic landforms, providing an excellent natural laboratory for investigating scoria cone evolution and structural controls. This study integrates morphometric, geochemical, and cosmogenic 36Cl exposure dating analyses to evaluate cone morphology, vent distribution, and post-eruptive surface evolution within the Orkhon–Selenge Volcanic Belt (OSVB). The scoria cones exhibit steep slopes, nearly circular cone geometries, and limited erosional modification, indicating relatively well-preserved geomorphic surfaces. Cone alignments and vent distributions closely correspond to regional fault systems, demonstrating that tectonic structures exerted a primary control on magma ascent and vent emplacement. Whole-rock geochemical analyses indicate alkaline basaltic to basanitic compositions typical of intraplate volcanism. Cosmogenic 36Cl exposure ages (~42–61 ka) primarily record late Pleistocene surface stabilization rather than the timing of volcanic eruptions. Variations in exposure ages likely reflect differences in post-eruptive erosion, surface modification, and local geomorphic processes. The discrepancy between published radiometric ages and cosmogenic exposure ages highlights the importance of distinguishing eruptive chronology from post-eruptive landscape evolution. Overall, our results provide new insights into the geomorphic evolution of monogenetic scoria cones and the role of tectonic structures in controlling intraplate volcanism in central Mongolia.