Observation of manganese deposits in the Mariana-Phillipine basin regions during SONNE cruise SO57

The MARIANA I- expedition had three main aims: 1) Performance of an ODP-site pre-survey of a serpentinite diapir in the Mariana fore-arc region; 2) Investigation of volcanism and hydrothermalism in the Mariana back-arc basin; 3. Investigation of the distribution of manganese nodules and crusts in the Philippine basin. During the transect across the Philippine basin, 7 different regions comprising a total of 37 stations were sampled. Investigations were carried out in areas over the Kyushu-Palau and Central ridges, as well as in one shallow-water and 4 deep (~ 5000 m) water regions scattered across the basin. The shallow-water station yielded manganese-nodule-covered, semilithified foraminiferal sand. Larger nodules (up to 10 cm in diameter) were found on the Kyushu- Palau ridge. They were associated with foraminiferal sand and carbonate ooze. In addition, hydrogenetic manganese crusts were also dredged at both the Kyushu-Palau and Central ridges.