Ferromanganese Nodules and Crusts from the Christmas Island Region, Indian Ocean

Authors: Exon N.F.; Raven M.D.; De Carlo E.H.

Source: Marine Georesources and Geotechnology, Volume 20, Number 4, 1 October 2002 , pp. 275-297(23)

Buy & download fulltext article:

Price: $56.94 plus tax (Refund Policy)

Abstract:

A sampling expedition has shown that largely hydrogenetic marine ferromanganese deposits occur in the Christmas Island region south of Java (~10°S), as small nodules on seamount slopes and abyssal plains (red clay), and as thick crusts on volcanic ridges and seamounts. Vernadite is dominant, with birnessite, jacobsite and todorokite common. Nodules were recovered in 25% of free-fall grab stations in water 4600-5900 m deep, and are not abundant where present. The nodules average 9.6% Fe, 19.7% Mn, 0.51% Ni, 0.49% Cu, and 0.12% Co. Crusts are common in water 1450-3700 m deep, with average deposition rates of 1-1.5 mm / m.y. The crusts average 13.9% Fe, 16.2% Mn, 0.35% Ni, 0.11% Cu, and 0.44% Co. Cobalt grades are higher (~0.8%) in shallower water ( < 2500 m), so future exploration should concentrate on depths of 500-1500 m near the oxygen minimum zone.

Keywords: FERROMANGANESE NODULES; FERROMANGANESE CRUSTS; HYDROGENETIC; DIAGENETIC; CHRISTMAS ISLAND; INDIAN OCEAN; DEEP OCEAN

Document Type: Research article

Publication date: 2002-10-01

More about this publication?