Understanding the tectonics of the Mikir massif, northeast India: insights from lineament analysis

Tectonically active regions show higher intensities of lineaments than tectonically quiet zones. Analyses of lineaments in an area where exposures are poor and covered by thick vegetation typically can provide indications of tectonic activities. The present work focuses on the use of remote sensing techniques and geographical information system (GIS) for the extraction and analysis of lineaments present in the Mikir massif of northeast India to understand the tectonic regime and correlate the results with regional geological structures. Landsat-8 and Shuttle Radar Topography Mission (SRTM) data has been used for manual extraction of lineaments in the study area. From the identified lineaments, various indices have been calculated and orientation analysis of lineaments has been done using rose diagrams. High-density zones of lineaments in the area are observed to be parallel to the Sarhed Fault and Kaliyani shear zone (KSZ), which dissected the central part of the massif. These are the areas of increased weakness, intense fracturing, and tectonically more active part in the study area. A tectonic model of the area is proposed based on the observed lineament fabric and also considering the sense of slip of the two major bounding faults (Kopili and Bomdila-Dhansiri Fault) in the area. The lineament fabric developed over the region is a manifestation of the Northwest-directed compression due to the oblique convergence of the Indian plate beneath the Burmese plate. This Southeast-Northwest compression, coupled with differential movement between the Kopili and Bomdila-Dhansiri Fault, leads to a resultant clockwise movement of the whole massif.