The continued convergence of India northward into Asia requires that intraplate shortening be taken up by crustal thickening along major thrusts and lateral extrusion of crustal blocks along strike-slip faults. Assessment of the relative contributions of these two mechanisms requires detailed measurement of vertical and horizontal motions on the major faults. The Ailao- Shan Red River fault in Yunnan, PRC is a Tertiary ductile strike- slip zone with up to 500km of left-lateral motion. This study will date the time of the end of left-lateral motion and start of the present regime of right-lateral and normal fault motion. It will also resolve the uplift rate during faulting by 40Ar/39Ar analysis of the exhumed fault rocks. The results of this study will significantly add to our understanding of the lithospheric response to crustal collision.
