• Facies characteristics of the basal part of the Talchir Formation, Talchir Basin, India – depositional history revisited

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      https://www.ias.ac.in/article/fulltext/jess/116/01/0015-0020

    • Keywords

       

      Gondwana sedimentation; Talchir Formation; Talchir Basin; debris flow; entrained turbidity current.

    • Abstract

       

      The lowest unit of the Talchir Formation of Talchir Basin, Orissa, was described by pioneer workers as the 'basal oulder bed'. In an attempt to explain the co-existence of gravel and clay, materials of contrasting hydraulic properties, a probable situation resembling the effects of the action of ground-ice enabled boulders to be carried down by sluggish currents resulting in an intermixture of large boulders and fine mud was conceived. Misinterpretation of this conclusion led to a general tendency to describe the 'basal boulder bed' as 'glacial tillite'. However, the unit described as 'basal boulder bed is actually represented by a matrix rich conglomerate with pockets of normally graded silty clay. The present study reveals that the depositional imprints preserved in this part of the sedimentary succession indicate emplacement of successive debris flows generated through remobilization of pre-existing unconsolidated sediments. Small pockets of fine-grained turbidites presumably deposited from the entrained turbidity currents associated with the debris flows suggest the composite character of the debris flow deposit.

    • Author Affiliations

       

      Prabir Dasgupta1 Rishiraj Sahoo1

      1. Department of Geology, Presidency College, 86/1 College Street, Kolkata 700 073, India.
    • Dates

       
  • Journal of Earth System Science | News

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