The southernmost thrust of the Himalayan orogenic wedge that separates the
foreland from the orogen, the Main Frontal Thrust, is thought to accommodate
most of the ongoing crustal shortening in the Sub-Himalaya. Steepened
longitudinal river profile segments, terrace offsets, and back-tilted fluvial
terraces within the Kangra reentrant of the NW Sub-Himalaya suggest Holocene
activity of the Jwalamukhi Thrust (JMT) and other thrust faults that may be
associated with strain partitioning along the toe of the Himalayan wedge. To
assess the shortening accommodated by the JMT, we combine morphometric terrain
analyses with in situ 10Be-based surface-exposure dating of the deformed
terraces. Incision into upper Pleistocene sediments within the Kangra Basin
created two late Pleistocene terrace levels (T1 and T2). Subsequent early
Holocene aggradation shortly before ~10 ka was followed by episodic
reincision, which created four cut-and-fill terrace levels, the oldest of
which (T3) was formed at 10.1 ± 0.9 ka. A vertical offset of 44 ± 5 m of
terrace T3 across the JMT indicates a shortening rate of 5.6 ± 0.8 to 7.5 ±
1.1 mm a−1 over the last ~10 ka. This result suggests that thrusting along the
JMT accommodates 40–60% of the total Sub-Himalayan shortening in the Kangra
reentrant over the Holocene. We speculate that this out-of-sequence shortening
may have been triggered or at least enhanced by late Pleistocene and Holocene
erosion of sediments from the Kangra Basin