Near-surface in situ stress. 4. Residual stress in the Tully Limestone Appalachian Plateau, New York.

The direction of maximum expansion during strain relaxation of the Tully Limestone at Ludlowville, New York, is within 2o of the strike of both set Ia cross-fold joints and the compression direction indicated by the teeth of tectonic stylolites. These joints and stylolites are members of a suite of structures accommodating approximately 9% layer-parallel shortening during the main phrase of the Alleghanian Orogeny within the Appalachian Mountains. Suggests that the expansion represents the relief of a residual stress locked into the Tully Limestone during the Alleghanian Orogeny. Using a flow law for pressure solution, infers that the Tully Limestone deformed at a strain rate of about 3 X 10^-15/s. Thus the layer-parallel shortening observed in the Tully Limestone may have required an aggregate deformation interval of only 1 Ma. -from Authors