Frank T. Manheim

TL;DR: Co-rich Fe-Mn crusts occur throughout the Pacific on seamounts, ridges, and plateaus where currents have kept the rocks swept clean of sediments at least intermittently for millions of years.

TL;DR: For example, the mean Fe/Mn ratios vary from about 24 000 (up to 58% elemental Fe) for hydrothermal seamount ironstones to about 0.001 (Up to 52% Mn) for Hydrothermal stratabound manganese oxides from active volcanic arcs as discussed by the authors.

TL;DR: Sedimentary iron and heavy-metal deposits of undetermined size have been found in the middle of the Red Sea some 2000 meters below the surface of the sea (Fig. 1). This discovery has been made from the Research Vessel Atlantis II, which is still at sea engaged in a series of oceanographic investigations which ultimately will end in November 1965, after the ship has circumnavigated the globe.

TL;DR: Pore fluid studies showed that relatively fresh to brackish water occurs beneath much of the Atlantic continental shelf, whereas increases in salinity off Georgla and beneath the Florida-Hatteras slope suggest buried evaporitic strata.

TL;DR: In this paper, the authors present maps of cobalt concentration and inferred accumulation rate of ferromanganese crusts from the Pacific Ocean, and propose an algorithm inversely relating cobalt content and crust growth rate with only indirect recourse to radioactivity-based dating methods.