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This paper presents a new interpretation of overlapping differential deformations and likely causes of the structural heterogeneity within the Kashmir basin. Representing a prominent and distinctive strain feature in NW Himalaya, the broad geomorphic expression of the Kashmir as an elongated NW-SE trending sedimentary trough is inconsistent with general compression governing structural trend and deformation pattern of ∼2500 km long Himalayan Frontal Thrust zone. In addition to the general extensional geometry, there are prominent anomalous deformation features at varied spatial scales in the basins that imply dominance of extensional tectonics. We infer that contrary to the overall compression dominant mechanism of the Himalaya, the apparent extensional geometry of the basin connotes orogen-parallel extensional deformation (pull-apart), triggered by oblique convergence in the NW Himalaya. Moreover, we construe that the comparatively younger contractile (positive) features in form of the geomorphic convexity (push-up), accompanied by out-of-sequence reverse faulting (Balapur Fault, hereafter called as BF) within the basin which is generally believed to be associated with the uplift along NE dipping southern thrust complex (MBT/MCT), possibly resulted due to the tectonic reversal (positive inversion). The presence of the compressional features within the locally predominant extensional setting is suggestive of the basin's hybrid character—where variable tectonic regimes (earlier extension and subsequent compression) seem to be coexistent. [ABSTRACT FROM AUTHOR]

The Balapur fault (BF) is a high angle thrust fault (reverse), dipping ~ 60° NE, with an established length of ~ 40 km striking NW–SE of the Kashmir basin. However, geomorphic traces suggest that the strike of the BF propagates beyond what has been documented previously. The present investigation aims to identify the unrecognized segment of the BF in the SW of the Kashmir basin using hypsometric variability in longitudinal profiles (knickpoints/zones), followed by validation through stream gradient index ( SL ) calculations of the rivers draining the area. The longitudinal profiles of all the streams indicate prominent and consistent anomalies in the upper and mid-reaches even on the coarse resolution data (Survey of India topographic maps — 1:50,000/40 m, DEM-SRTM 90 m). The profile anomalies in the upper reaches (hard rock zone) of the streams may be attributed to lithological contacts, i.e., Panjal trap agglomeratic slate–shale–limestone. However, the river profile convex segments and course deflection specifically in the mid-reaches (soft rock zone) are most likely associated with recent tectonic activity. Geomorphic signatures suggest that these anomalies coincide with the strike of the recognized segment of the BF. Moreover, the SL values of each stream express a clear agreement with the anomalies shown by the long profiles of the rivers. Hence, we infer that the strike of the BF extends for a significant distance (~ 95 km) over the northeastern flank of the Pir Panjal range in the NW–SE direction. [ABSTRACT FROM AUTHOR]

Geomorphology has long been recognised as a key to evaluate the interplay between tectonics and landscape geometry in the regions of active deformation. We use geomorphic signatures at varied spatial scales interpreted from SRTM-DEM/Landsat-ETM data, supplemented with field observations to review the tectonic evolution of Kashmir basin in northwest Himalayas. Geomorphic evidence is persuasive of a credible NNW–SSE trending dextral strike–slip structure (central Kashmir Fault — CKF), with the strike length of ~ 165 km, stretched centrally over the NNW–SSE length of the Kashmir basin. As a result of the strike–slip motion and subsequent erosion, significant deformation has taken place along the CKF. In addition, broad geomorphic architecture of the basin reveals typical pull-apart characteristics. Hence, we deduce that the Kashmir basin has evolved as a pull-apart Quaternary sediment depression owing to the deformation along the central Kashmir Fault. The spatial distribution pattern of seismic events (NEIC-catalogue, 1973–2013) and GPS measurements (published), collectively substantiate our geomorphic interpretations. [ABSTRACT FROM AUTHOR]