Geology of eastern New World Island, Newfoundland: An accretionary terrane in the northeastern Appalachians

Eastern New World Island is located in the northeastern part of the Dunnage Zone of the Newfoundland Appalachians. Contrary to previous interpretations, deposition of the sedimentary sequences in this area took place in a single basin, although styles of deposition varied laterally within this basin. Four generations of deformation have affected these rocks. D₁ deformation was progressive and highly heterogeneous, and it is associated with thrusting. Movement zones are present at the bases of thrusts, locally with zone-parallel cleavage (S₁). These zones show a complex deformation history. Folds overprinted by cleavage, folds with axial plane cleavage, and folded cleavages all occur. Movement zones are locally associated with technically deformed olistostromes. Repetition of the general stratigraphic sequence occurs as a consequence of D₁ thrusting. The thrusting direction on eastern New World Island, however, cannot be unequivocally determined.

Superimposed on D₁ deformation, there is regional folding (F₂), with a well-developed regional S₂ axial plane cleavage. Two types of F₃ folds are present, and these are associated with strike-slip faulting. F₄ deformation caused the formation of minor kinks. D₁ deformation is Lower Silurian and younger in age and is included in the Acadian orogeny of the Appalachians. Evidence for earlier, Taconic, deformation is absent.

The over-all geometry of eastern New World Island is that of a steeply dipping thrust pile with a complex internal geometry. It strongly resembles parts of the imbricate fan complex of the Southern Uplands of Scotland.