Genesis of Central Indian Ocean basin seamounts: morphological,petrological, and geochemical evidence

International Journal of Earth Sciences - We present the petrological investigation carried out of the seamounts located between water depths of 4300 and 5385 m in the Central Indian Ocean...     

Trace elements in ferromanganese nodules from the central indian ocean basin

Thirty-three bulk ferromanganese nodules from the sediment–water interface of siliceous sediment domain from the Central Indian Ocean Basin were analyzed for 50 elements including 6 new (Be, As, Se, Sn, Sb, and Bi) using inductively coupled plasma–mass spectrometer. The Mn/Fe ratio and triangular plot (Fe-Mn-{Cu+Ni+Co?×?10}) suggest that ferromanganese nodules are of hydrogenetic, early diagenetic, and diagenetic origin. In the ferromanganese nodules, Mo, Sb, Bi, and As are highly enriched ～320, 160, 90, and 50 times compared with upper continental crust, respectively. A majority of the elements such as Be, Sc, Ti, V, Co, As, Se, Sr, Y, Zr, Nb, Sn, rare earth elements (REEs), Pb, Bi, P, Th, U, Hf, and Ta are associated with Fe, whereas, Cu, Ni, Zn, Mo, Li, Ga, Sb, Mg, and Cs are associated with Mn in the ferromanganese nodules. Redox proxies such as U/Th (0.14) and Mo/Mn (0.0019) ratio in the ferromanganese nodules suggest their formation under oxic conditions.