Abstract

Rocks outcropping in the northernmost part of the island of Newfoundland belong to two sequences, which are partly contemporaneous and very different in lithology. One sequence consists of Lower Cambrian sandstones and Lower and Middle Ordovician carbonates and shales. The other sequence consists of graywackes, volcanic rocks, and ultrabasic intrusions, which are, in part, early Ordovician. This latter sequence is interpreted as allochthonous because it is underlain by major low-angle faults and because of its strong facies contrast with the first sequence. The allochthonous rocks occur in three separate klippen.The trend of slickensides, attitude of folds, and deflection of beds at fault surfaces all indicate that movement along the low-angle faults that underlie the klippen was to the northwest. The klippen probably originated from an area 60 km to the southeast, which is on strike with similar rocks in north-central Newfoundland.It is suggested that the klippen moved by gravity sliding in late Middle Ordovician time.

You do not currently have access to this article.