Mesozoic Rocks from the Labrador Sea

Abstract

THE existence of Mesozoic rocks on the continental shelf of Greenland has been postulated by several authors^1–4. During the summer of 1971 the US Naval Oceanographic Office conducted a reconnaissance survey in the southern Labrador Sea, which also included rock dredging on the south-western margin of the Greenland continental block. As well as containing deep glacially cut Canyons, the continental slope of south-west Greenland is swept by swift bottom currents and therefore has not prograded as extensively as most continental slopes throughout the world. It is therefore a better than usual structure for dredging operations. The results of any rock dredging operation in northern waters are, of course, immediately open to suspicion of ice-rafted contamination. McMillan⁵ summarizes the problem and concludes that most glacial erratics are derived locally. Indeed, we did collect a fine suite of glacial erratics. The data presented in Table 1 are, however, believed to represent in situ samples, and their homogeneity lends support to this. In dredge 43 (Fig. 1), for example, the entire dredge haul (˜100 pounds) consisted of sandy limestone.