Journal - Finite strain variation across the Mahabharat Thrust in central Nepal Himalaya

Finite strain variation across the Mahabharat Thrust in central Nepal Himalaya

Deepak Chamlagain

Simulation Tectonics Laboratory, Faculty of Science

Daigoro Hayashi

University of the Ryukyus, Nishihara, Okinawa 903-0213, Japan

Jour. Nepal Geol. Soc., Vol. 35, 2007, 11-20


This paper deals with the three-dimensional strain across the Mahabharat Thrust (MT) in the Malekhu area in central Nepal. The MT served as a glide plane for the Kathmandu Nappe. Its footwall is made up of phyllites, quartzites, and amphibolites, whereas the hanging wall contains garnetiferous schists, biotite schists, and quartzites with a few lenses of augen gneiss. A three-dimensional strain analysis reveals that Nadai’s amount of strain intensity (e s ) ranges from 0.396 to 0.575 in the footwall indicating an increasing trend towards the proximity of the MT. In contrast, the hanging wall shows an increase in e s magnitude away from the MT and its value varies between 0.556 (at the basal part) and 0.795 (upper part). Microtextures and structures revealed dynamic recrystallisation of the footwall and static recrystallisation of the hanging wall rocks. The shape of three dimensional strain ellipsoids, types of microstructures, and mechanisms of grainscale deformation indicated that the footwall was dominantly affected by simple shear deformation at lower temperatures while the hanging wall suffered from pure shear with minor sub-simple shear deformation at relatively higher temperatures.

Member Login
  • Jul

    Academic and professional development Sub Committee of the Nepal Geological Society and Nepal Geological Students’ Society in collaboration with Central Department of Geology has organized a training and interaction program entitled “Mining and Engineering Geology in field” on 23rd  Asadh 2075 at the conference hall of the Central Department of Geology, Kirtipur.

  • May

    Nepal Geological Society has organized a press meeting on the memory of 2015 Gorkha Earthquake on 2075/1/12 at the conference hall of Department of Irrigation, Jawalakhel

Activities and Information

Activities of 17th and 18th Executive Committee
Nepal Geological Society
P.O.Box No. 231
Kathmandu, Nepal
FREEPHONE: +977-01-4437874