Aseismic Tectonism-Induced Soft-Sediment Deformation in a Tranquil Palaeogeography: Chikkshelikere Limestone Member, Proterozoic Kaladgi Basin, Southern India Soumik Mukhopadhyay, Adrita Choudhuri, Nivedita Chakraborty and Subir Sarkar Abstract The wide spectrum of synsedimentary deformation products occurring almost at all stratigraphic levels within the *40 m-thick section of the Chikkshelikere Limestone Member of tentative Mesoproterozoic age in India is evaluated for its origin. Among the two principal facies components, both car- bonate, of this Member the dark micritic facies generally underwent brittle defor- mation, and the light microsparry facies responded in ductile fashion to the same deformational stress. Breccia patches, hardly having any boundary, abound at almost every stratigraphic level within the Chikkshelikere Limestone Member. The third facies constituting less than 3% by volume of the Member is of laterally persistent carbonate intraclastic conglomerate beds. The dark facies is of massive micrite, while the light facies is made up of interlocking microspar crystals, but bears minor wave-current structures, and rare minute erosional features at its base. Non-luminiscent character of the former under CL is reminiscent of oxidizing basin-floor environment, while the bright orange luminescence of the latter testifies pervasive burial recrystallization. The dark micritic facies is interpreted as indige- nous and the light microsparry facies as allochthonous, possibly laid by highly energy-depleted storm wave-cum-current. Mineralogical as well as geochemical analyses indicate preferred dolomitization and carbon enrichment in the dark micritic facies. Selective pyritization is also observed along the base of the same facies. These features collectively suggest selective microbial mat proliferation within this facies. Despite early induration being the rule for carbonate sediments, microbial mat growth apparently enhanced its rate within the dark micritic facies S. Mukhopadhyay (&) Á A. Choudhuri Á S. Sarkar Department of Geological Sciences, Jadavpur University, Kolkata 700032, India e-mail: soumikjugeo03@gmail.com N. Chakraborty Department of Geology, K.J.R. Government General Degree College, Mejia, Bankura 722143, India © Springer International Publishing AG, part of Springer Nature 2019 M. E. A. Mondal (ed.), Geological Evolution of the Precambrian Indian Shield, Society of Earth Scientists Series, https://doi.org/10.1007/978-3-319-89698-4_15 351