Structural and magnetic fabric studies of recess structures in the western Himalaya: Implications for 1905 Kangra earthquake

Abstract

Kinematic information from deformation structures and magnetic fabrics are used to infer recent tectonics around Kangra and Dehradun recesses, western Himalaya. Three types of magnetic fabrics (Type I & II, III, and IV) are identified based on the angle between K3 axis and bedding pole. It was observed that Kangra recess shows more mature fabric type IV as compared to Dehradun recess, where orientation of K3 axes and tectonic fabric reveals dominance of superposed deformation. In the vicinity of Dehradun recess, normal faults occur in un-indurated Quaternary fan deposits confirming their recent formation. The observations are in conformity with earlier studies that during the 1905 Kangra earthquake, the Main Boundary Thrust (MBT) (or one of its subsidiary thrusts) near Kangra showed thrusting whereas the MBT near Dehradun underwent either normal faulting or post seismic adjustments characteristic of normal faulting. The thrusting could be a result of subsurface processes whereas the normal faulting was a result of prevailing surface strains.

Magneto-Mineralogical Characterization and Manifestations of Magnetic Fabrics from the Gneissic Rocks and Associated Intrusive Bodies in and around Bankura and Purulia Districts, West Bengal, India

“…Oriented samples are of utmost importance for carrying out magnetic susceptibility and AMS 11 studies. Suitable locations were selected, from which 6-8 oriented cores (diameter of 2.54 cm and height of 2.2 cm) were drilled using a portable drilling machine 12,13 . Twenty five locations were selected for collection of oriented cores.…”

Arc-parallel compression in the NW Himalaya: Evidence from structural and palaeostress studies of brittle deformation from the clasts of the Upper Siwalik, Uttarakhand, India

“…E1, E2: early formed strike-slip faults. S1-S3: late strike-slip faults (Jayangondaperumal et al 2010). SJ: study area of Srivastava and John (1999), MHT: Main Himalayan Thrust, MFT: Main Frontal Thrust, MBT: Main Boundary Thrust, BBT: Bhimgoda Back Thrust, YTF: Yamuna Tear Fault, GTF: Ganga Tear Fault, DHR: Delhi-Haridwar Ridge (blue arrows indicate the lateral extremities of the DHR); DL: Dehradun Lineament (Godin et al 2018); MDF: Mahendragarh-Dehradun Fault (Sandhu et al 2017); RA: Raiwala Anticline, NH: Nagsidh Hill (Jayangondaperumal et al 2010).…”

Back-thrusting in Lesser Himalaya: Evidences from magnetic fabric studies in parts of Almora crystalline zone, Kumaun Lesser Himalaya

“…The collision shortened the crust and developed three major south-verging thrust systems known as Main Central Thrust (MCT) (active from 20.8 ± 1.1 to 15.0 ± 2.4 Ma, Tobgay et al 2012), Main Boundary Thrust (MBT) (∼11 Ma, Meigs et al 1995), and Himalayan Frontal Thrust (HFT) (initiation age between 500 and 100 Ka, Thakur 2013), from north to south respectively (see Seeber and Armbruster 1981;Srivastava and Mitra 1994;Mukherjee et al 2015;Dubey 2014). The MCT and MBT delineate the Lesser Himalayan sequence in Kumaun region from the Higher Himalaya in north and the Siwalik (sub-Himalaya) in south, respectively (Nakata 1989;Jayangondaperumal et al 2010). The sedimentary formations of the Lesser Himalayan sequence (LHS) are tectonically overlain by several klippen consisting of largely amphibolite facie metamorphic rocks, and intrusive and basement granites, belonging to the Precambrian Almora group.…”