Deciphering tectonic uplift and landscape evolution through geomorphic indices: insights into low- and high-angle fault interactions in the Bozdağ High, Western Anatolia

The Bozdağ High is a metamorphic core complex located between the Gediz (Alaşehir) and Küçük Menderes grabens in the Western Anatolia Extensional Province. The region is structurally controlled by low-angle Gediz Detachment Faults (GDF) and high-angle normal faults, which play a fundamental role in its geomorphological evolution. Understanding how these fault systems interact to shape uplift, drainage reorganization, and landscape dynamics remains an open scientific question. This study utilizes GIS-based morphometric analyses of 53 drainage basins and mountain fronts to quantify the spatial variations in uplift and fault activity. By integrating geomorphic indices (e.g., χ-index, k_sn, S_mf, V_f) with analytical hierarchy process (AHP) models, we assess relative tectonic activity and investigate the kinematic evolution of fault-bounded blocks. Our findings reveal that the Bozdağ High experienced distinct rotational phases before and after the activation of high-angle faults, transitioning from an initial detachment-dominated extensional system to a segmented fault network. Additionally, Bozdağ High exhibits contrasting tectonic activity between its northern and southern flanks. While the northern flank, facing the Gediz Graben, experiences higher uplift rates and stronger tectonic forcing, the southern flank, adjacent to the Küçük Menderes Graben, exhibits relatively subdued tectonic activity and increased erosional modification. The western section of the eastern flank shows a more rapid uplift trend toward the east, whereas the southern flank displays significant surface tilting. Geomorphic evidence suggests that sequential fault activity and strain partitioning control differential uplift, drainage divide migrations, and basin asymmetry. Asymmetric basins in the southern sector, characterized by high hypsometric integral (HI) and low normalized steepness index (k_sn) values, suggest a balance between erosional processes and tectonic uplift. In contrast, regions with ongoing rapid uplift exhibit higher k_sn values and active knickpoint formation. These results provide new insights into the interaction between low- and high-angle fault systems and contribute to the broader understanding of tectonic evolution in extensional provinces. These new insights include the identification of spatially variable uplift and rotation patterns caused by sequential activation of low- and high-angle faults, revealing how block tilting and strain partitioning have shaped drainage reorganization and landscape evolution in the Bozdağ High.