Marine mineral exploration—realities and strategies at the end of the 1990s

A brief summary of past marine mineral exploration strategies is given and compared to present strategies. Focus is presently on exploration efforts in the Exclusive Economic Zones (EEZs), particularly in the coastal and near-coastal realms, although ferromanganese nodules and massive sulfides at mid-ocean ridges are still of significant interest. A relatively new radiometric mineral exploration tool, assaying the ocean floor through continuous measurement by gamma-ray spectrometry, is described. Preliminary data gathered with a prototype sonde in Danish waters are presented.