RARE-EARTH ELEMENTS IN MANGANESE NODULES FROM THE CENTRAL PACIFIC-OCEAN

Manganese nodules in areas CP and CC of the central Pacific are rich in REE. Comparatively speaking. the REE contents of nodules in area CP are higher than those in area CC; and the REE contents of nodules from seamounts are higher than those of nodules from sea-floor plains and hills. Within the nodules, the REE show a zonal distribution. The REE distribution patterns of the nodules are similar to those of the sediments and have a mirror image relationship with those of the sea water. Trivalent REE were not obviously differentiated when they entered into the nodules from the sea water. A major factor causing the difference of REE abundances between nodules and sediments is the redox conditions. The redox intensity of the ocean floor of the Pacific is controlled mainly by Antarctic Bottom Water (AABW). The iron-bearing facies in the nodules is the main carrier of REE.