Most fault-controlled basin formation within plate interiors occurs by normal faulting in response to horizontal deviatoric tension in the continental crust. It is suggested that the tension originates either from the plate boundary forces acting at trenches or as a result of isostatically compensated uplifted regions such as East Africa. The tension produced by both mechanisms is greatest in high heat-flow regions where the upper elastic part of the lithosphere is thinned and weakened. Particularly widespread tension in the continental lithosphere occurs when subduction takes place on opposite sides of a large continental mass, such as Pangaea in the early Mesozoic, where it led to widespread graben formation and, in association with hot spot activity, to continental splitting.