CARBONIFEROUS ROCKS OF THE CONCHE – GROAIS ISLAND AREA, NEWFOUNDLAND

Abstract

About 5 000 ft of Carboniferous sedimentary strata occur in the Cape Rouge and Conche peninsulas, small projections on the east side of the Great Northern Peninsula of Newfoundland. The lower 900 ft of the section consists of coarse conglomerate and sandstone, the fragments in which were derived from nearby older rocks. These lower beds are overlain by about 4 000 ft of shale and sandstone, in places petroliferous and with bituminous residues, and bearing plants and spores identified as of upper Horton (late Tournaisian) age. The sedimentary rocks described in this paper are the northernmost known Carboniferous rocks of the Appalachian belt. They lie in a basin between Groais Island and the Great Northern Peninsula and may possibly be continuous under the sea with the Grand Lake–White Bay basin a 100 mi to the southwest. The boundary fault on the west side of this Carboniferous basin is a portion of a fault system which is known to extend some 300 mi from the northern tip of Newfoundland to its southwest corner and is a portion of the Cabot fault of Wilson. Movement on the fault system appears to have been of at least three ages, pre-Horton (pre-Tournaisian), post-Horton–pre-Windsor (post-Tournaisian–pre-Visean), and post-early Pennsylvanian (post-Westphalian "A").