tells you Extensional tectonics is associated with the stretching and thinning of the crust or lithosphere. This type of tectonics is found at divergent plate boundaries, in continental rifts, during and after a period of continental collision caused by the lateral spreading of the thickened crust formed, at releasing bends in strike-slip faults, in back-arc basins and on the continental end of passive margin sequences where a detachment layer is present.