Annotated record of the detailed examination of Mn deposits from the VERMILION SEA Expedition stations

On Vermilion Sea Expedition two research vessels among which the R/V Spencer F. Baird conducted a geological and geophysical exploration of the Gulf of California from February to May, 1959. Support was obtained from the Office of Naval Research and the Bureau of Ships of the U. S. Navy and from a grant of the American Petroleum Institute. Study of the canyons was one feature of the first part of the expedition. Submarine canyon studies were directed by Francis P. Shepard, Professor of Submarine Geology, aboard the research vessel Spencer F. Baird. The expedition found that the narrow channel between Angel de la Guarda Island, toward the head of the Gulf, and the peninsula is scoured almost free of sediments by strong currents. On the other side of Angel de la Guarda Island, between it and the mainland, one of the dredge hauls brought up a manganese nodule. It came from a depth of approximately 1500 feet. This is the shallowest water in which the nodules have been found. Studies have been under way some time on the feasibility of mining such nodules from the sea floor. They contain cobalt, nickel, copper and other valuable metals. (also in, Scripps Institution of Oceanography Vermilion Sea Expedition to the Gulf of California, http://library.ucsd.edu/dc/object/bb34484017)

Investigation of manganese nodules from the Southern Tasman Sea

Two manganese nodules having a high clay content, a low Mn/Fe ratio, and low contents of valuable metals (Ni 0.25%, Cu 0.17%, Co 0.06%) were recovered in a grab sample during a short geological cruise in HMAS Kimbla in the southern Tasman Sea in May 1979. Five stations were occupied. Free-fall grabs recovered sediment or pumice from four stations; nothing was recovered from the fifth. The carbonate compensation depth in the region is about 4500 m. Reddish brown clay, but no manganese nodules, was recovered in the central southern Tasman Sea, from depths of 4900-5100 m. The nodules, together with grey calcareous mud, were obtained from a depth of 4300 m, farther to the northwest, near Gascoyne Seamount (250 n. miles SE of Sydney). The results suggest nodules with high metal values are likely to exist only in the broad and deep depression in the central southern Tasman Sea southeast of Gascoyne Seamount, where sedimentation rates are low and oxidising conditions prevail. Whether nodule fields are present or not will only be resolved by considerably more sampling.