Facies characteristics of the basal part of the Talchir Formation,Talchir Basin,India — Depositional history revisited |
| |
Authors: | Prabir Dasgupta Rishiraj Sahoo |
| |
Institution: | (1) Department of Geology, Presidency College, 86/1 College Street, Kolkata, 700 073, India |
| |
Abstract: | The lowest unit of the Talchir Formation of Talchir Basin, Orissa, was described by pioneer workers as the ‘basal boulder
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. |
| |
Keywords: | Gondwana sedimentation Talchir Formation Talchir Basin debris flow entrained turbidity current |
本文献已被 SpringerLink 等数据库收录! |
|