EVIDENCE FOR ALLEGHANIAN DEFORMATION IN THE CHAMPLAIN VALLEY, VERMONT

Recent mapping in the parautochthonous shales beneath the Taconic and Champlain thrust sheets has discovered localized sets of folds, thrust faults and cleavage that are at high angle to all other contractional structures in the Champlain valley. These structures are clearly later than all other recognized contractional structures, deforming the overlying thrust sheets and cutting regionally developed foliations, many of which have been linked to Acadian deformation. Recognition of these structures provides a basis for explaining a number of regional structural anomalies.

The orientation of these new structures, approximately N60E strike, is highly oblique to all other regional structures, which strike roughly north. This orientation is usually considered to be Alleghanian when encountered farther south in the Hudson valley, and that interpretation is consistent with the structural relations in the Champlain valley.