ABSTRACT

Examination of folds in the Lower Cretaceous Shaftesbury formation indicates that they are imperfectly cylindrical and of concentric type. Fold axes trend N50°W and plunge an average of 05° southeast while axial planes vary in dip from 55°E to 80°W. Geometry of the folds suggests that local structural separation exists between the Shaftesbury and the overlying Dunvegan formation.

The origin of small faults with diverse orientations is not apparent, but later slickensides on the fault surfaces and on bedding indicate a mean trend of tectonic transport(a) of N50°E and extension either in a vertical direction or normal to the fold limbs. Joints dip almost normal to bedding and show three main trends of N30°E, N-S, and N60°W. Two of these may represent extension fractures parallel to "a" and "B;" the relationships of the N-S set are not clear.

Orientation of the general stress system thought to be responsible for the macroscopic folds is apparently supported statistically by evidence from mesoscopic structures.