Abstract
In the Kolar Schist Belt well-preserved small-scale diastrophic structures suggest four phases of folding (F1 — F4). The near coaxial F1 andF 2folds are both isoclinal with long-drawn out limbs and sharp hinges. The axial planes of bothF 1andF 2folds are subvertical with N-S strikes; these control the linear outcrop pattern of the Schist belt. The later folds (F 3and F4) are important in small-to-intermediate scales only and are accommodation structures formed during the relaxation period of the early folding episodes. Mesoscopic shear zones, post-F2 but pre-F3 in age, are present in all the rock types in this area. The F1 and F2 folds and the mesoscopic shear zones were formed during a continuous E-W subhorizontal compression. Available geochemical and isotopic data show that the Kolar Schist Belt with ensimatic setting is bounded by two granitic terrains of contrasting evolutionary histories. This, together with E-W subhorizontal compression over a protracted period of time, strengthens the recent suggestions that the Kolar Schist Belt represents a suture. This belt then marks the site of a continent-continent collision event of late Archaean-early Proterozoic age.
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Mukhopadhyay, D.K. Deformational history of the Precambrian Kolar Schist Belt, South India: Constraints for the tectonic evolution. Proc. Indian Acad. Sci. (Earth Planet Sci.) 99, 201–213 (1990). https://doi.org/10.1007/BF02839390
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DOI: https://doi.org/10.1007/BF02839390