Tectonic geomorphological аnalysis of the Khukh Lake Basin, Mongolian Altay Mountains, north-west Mongolia

Монгол Алтайн нурууны Хөх нуурын хотгорын тектоник геоморфологийн шинжилгээ

Abstract

The Khukh Lake Basin in the Mongolian Altay represents a characteristics of a tectonically formed lake basin. This study employed a comprehensive morphometric analysis to determine the morphological development, origin, and tectonic influence on the basin. Using topographic maps, satellite imagery, digital elevation models (DEMs), and field measurements, we applied various analytical methods including Topographic Analysis (TA), Hypsometric Integral (HI), Valley floor (Vf), Mountain Front Sinuosity (MFs), Basin Shape Index (Bs), Relief Slope (RSl), Relative Relief Energy (RE), Hypsometric Curve (HC), and Volume Estimation (V). The results reveal that the Khukh Lake Basin is aligned along a NW–SE-trending fault system and is situated within an active tectonic zone characterized by compressional and transtensional deformation. Morphometric analysis of the study area revealed a hypsometric integral (HI) of 0.80%, Vf values ranging from 0.11 to 0.35, surface slopes between 44° and 68°, RE of 1142 m, a Bs value of 2.33, and an MFs value of 1.0. These results indicate that the lake was formed within a narrow, elongated tectonic zone extending from northwest to southeast. The average volume of the non-linear body was estimated to be 0.069 km³, suggesting that the Khukh Lake was formed by a rock blockage of this volume. Morphometric indicators collectively confirm the presence of intense tectonic activity, substantiating the structural control over the basin's formation and evolution. This research highlights the geodynamic significance of the Mongolian Altay region, where active faulting plays a crucial role in shaping lake basins, and provides a scientific basis for understanding tectonic influences on intramontane depressions.