Quaternary alluvial fans in the tectonically active Pinjaur Dun, an intramontane valley in the Sub‐Himalaya, were deposited in front of the Nalagarh Thrust and were influenced both by tectonics and glacial climate fluctuations. The surface morphology indicates that an earlier set of first‐order fans (Qf1) became entrenched and onlapped by a series of second‐order fans (Qf2). The younger fan segments were then cut by a pair of terraces (T1 and T2). Quartz optically stimulated luminescence dating establishes that the Qf1 aggradational phase was initiated before 96·5 ± 25·3 ka and terminated after 83·7 ± 16·3 ka. This was followed by a period of incision, before Qf2 fan deposition started at 72·4 ± 13·4 ka and continued until 24·5 ± 4·9 ka. Sediment was deposited on the T1 (upper) and T2 (lower) terraces at 16·3 ± 2·1 and 4·5 ka, respectively, recording a return to overall degradation punctuated by minor deposition on terraces. The period of incision separating the younger and older fan deposits coincided with enhanced SW monsoon precipitation. The subsequent development of the Qf2 fans and their progradation until 20 ka suggest erosional unloading of the thrust hangingwall during a tectonically quiescent phase. Toe cutting, deposition of axial river and lacustrine facies, and retreat of Qf2 around 45 ka, indicate fanward shift of the axial river due to tilting of the valley towards the NE in response to reactivation of the Nalagarh Thrust. The cessation of Qf2 deposition around 20 ka and the onset of through‐fan entrenchment suggest reduced sediment supply but relatively high stream power during the last glacial maxima (LGM). The prolonged stream incision since the cessation of Qf2 deposition, with only minor depositional phases at 16·3 ± 2·1 and 4·5 ka, resulted from high water discharge and low sediment input during intensification of the SW monsoon and vegetation changes in the hinterland.

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A dynamic coupling between climate-induced erosion and tectonics is envisaged for the growth of the Himalaya. The Dhauladhar Range (NW Himalaya), between the Beas and Ravi rivers, shows large altitude variation along the regional trend from southeast to northwest. The altitude rises between 5000 m and 4000 m in the eastern part and decreases between <4000 m and 2800 m in the western part. Eastern part of the Range is characterized with focused and highest precipitation, concentration of microseismicity and the formation of Kangra Basin to its south; whereas all these features are lacking in the western part. The Kangra Basin is a post-Siwalik intermontane basin between the Dhauladhar Range in the north and the Siwalik Range in the south. The basin-fill is essentially derived from the southern flank of the Dhauladhar Range as a consequence of erosion due to deglaciation. The Kangra Basin is developed as a piggy-back basin over the hanging wall of the foreland propagating Jawalamukhi Thrust (JT). The Optically Stimulated Luminescence (OSL) dating of fluvial strath terrace surfaces, across the hanging wall, indicate late Quaternary reactivation of the JT. The Kangra Basin sediments yield late Quaternary OSL ages similar to that of the strath terraces. This suggests that formation of the Kangra Basin is synchronous with reactivation of the JT, implying a linkage among formation of the Kangra Basin, its filling through erosion of the Dhauladhar Range and reactivation of the Jawalamukhi Thrust.

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