Evidence of Late Quaternary seismicity from Yunam Tso, Lahaul and Spiti, NW Himalaya, India

Journal of Earth system science

Amzad H Laskar3³  Archna Bohra1²  B S Kotlia2¹  M G Yadava3³ 

[1] Department of Geology, Kumaun University, Nainital 263 002, India.$$;Centre for Glaciology, Wadia Institute of Himalayan Geology, Dehra Dun 248 001, India.$$;Geosciences Division, Physical Research Laboratary, Navrangpura, Ahmedabad 380 009, India.$$

关键词: Quaternary;    fluvio-lacustrine sediments;    Baralacha La (La = Pass);    Yunam Tso (Tso = river);    soft sediment structures and seismites.;   

DOI  :  

学科分类：天文学(综合)

来源: Indian Academy of Sciences

【 摘 要 】

A relict fluvio-lacustrine sediment of an 8 m thick section exposed at Kilang Sarai along Yunam river, near Baralacha La shows presence of cycloids or pseudonodules, ball and pillow structures, flame-like and pocket structures, sand dyke injections, bed dislocation/faulting and flow folds. Within this section four deformed levels of soft sediment structures have been identified which were dated ca. 25 ka BP at level 1 (∼0.4 m from the modern river level (mrl), 20.1 ka BP at level 2 (∼1.8 m mrl), 17.7 ka BP at level 3 (∼2.56 m mrl) and 12.2 ka BP at level 4 (∼4.25 m mrl)). Detailed study of these soft sediment structures allow us to demonstrate that deformation level 3 is not related to seismic trigger, but remaining three deformation levels (1, 2 and 4) are ascribed to seismic origin. From compilation of earlier palaeoseismological studies using soft sediment deformational structures (SSDS) in the palaeolake deposits in the adjoining area, suggest that the deformational events identified in the present study are regional in nature and thus tectonic process plays an important role in the evolution of landform in the Spiti region.

【 授权许可】

Unknown