Study of structural, deformation temperature, and strain analysis of the quartzarenites of south-central Kaladgi basin, exposed at and around Mullur ghat and Kallur village of Belgaum district, Karnataka, India

Abstract

Kaladgi rocks are magnificently exposed in Belgaum district of Karnataka state, with adjacent to Maharashtra, the Kaladgi Basin, evolved as a consequence of crustal extension which are resting on the basement of the Archaean Gneisses and are also overlaid by Deccan Traps. The outcrops in the present study area have very well-exposed quartzarenites of south-central part of Kaladgi Basin. New meso- and microscale structural analyses indicate that Kaladgi rocks suffered at least two episodes of deformation preserved in ductile and ductile-brittle structures. Finite strain analyses of the XZ and YZ sections on the collected samples from the Kaladgi basin show pure flattening strain pattern on Hsu and Flinn diagram. This simple flattening strain is attributed due to the sedimentation or lithological loading in the basin. This study area traversed by 3 transverse faults, namely F1, F2, and F3 through K-1, K-5, and M-4 locations, respectively. Finite strain analyses show high strain value in XZ section along the faults as F1 show 1.32 to 1.44, F2 has 2.3 to 1.45, and F3 reflect 1.57 Rs values. Deformation temperature based on the microstructures has high value along the faults as 400 to 500°C; however, rest of the area show low temperature deformation <300°C. This study brings new insights on deformation structures in field and under a microscope.