The Northwest Atlantic Mid-Ocean Channel of the Labrador Sea. IV. Petrography and provenance of the sediments
The Northwest Atlantic Mid-Ocean Channel (NAMOC) of the Labrador Sea is associated with a 500 m thick sequence of well-bedded turbidites along the axis of the Labrador and Newfoundland basins and extends onto the western Sohm Abyssal Plain. The specific source areas of these terrigenous turbidites on the shelves and landmasses surrounding the Labrador Sea were not known hitherto because the morphological connections in the head region of the NAMOC with canyons on the slope are masked by young ice-rafted and bottom-current-transported sediments.Petrographic analysis of channel sands and gravels suggests a dominant Canadian source for the channel segment north of the confluence with the Imarssuak Mid-Ocean Channel (IMOC) based on the predominance of lower Paleozoic detrital carbonates. The IMOC provides sediment from sources around the West Reykjanes Basin, i.e., the east coast of Greenland and Iceland; however, source-specific minerals or rock fragments from the Tertiary alkali basalts of southwest Greenla...