DISPLACEMENT TRANSFER AT THRUST TERMINATIONS - THE SALTVILLE THRUST AND SINKING CREEK ANTICLINE, VIRGINIA, USA

The Saltville thrust terminates in the core of the Sinking Creek antic line. Changes in the amplitude of the anticline may preserve profile s hortening as the thrust displacement decreases towards the fault termi nation. Consequently, thrust displacement would be transferred into th e fold. We combine newly published maps and new strain and mesostructu ral data from the Tuscarora Sandstone to argue that the Sinking Creek anticline did perform this kinematic role. We propose that the anticli ne developed as a fault-propagation fold that experienced both decolle ment and anticlinal breakthrough by the Saltville thrust. Thrust displ acement was accommodated by the development of the modified fault-prop agation fold and by transfer to a roof flat from the decollement break through. New strain and mesostructural data indicate no fixed pin line s in either the hinge or backlimb throughout folding. Consequently, la yer slip occurred through the hinge during folding and the forelimb de formed internally during breakthrough. Towards the plungeout of the Si nking Creek anticline, the displacement on the Saltville thrust is tra nsferred to a floor thrust. We apply this interpretation to the termin ation of the St. Clair thrust, which has a similar surface geometry wh ere the thrust terminates into an anticline. A testable implication of this proposed interpretation for the St. Clair thrust is that the App alachian Plateau must absorb over 20 km of thrust displacement as hori zontal shortening.