MANGANESE NODULES
D. S. Cronan, Royal School of Mines, London, UK
Copyright & 2001 Elsevier Ltd.
Introduction
Manganese nodules, together with micronodules and
encrustations, are ferromanganese oxide deposits
which contain variable amounts of other elements
(Table 1). They occur throughout the oceans, although the economically interesting varieties have a
much more restricted distribution. Manganese nodules are spherical to oblate in shape and range in size
from less than 1 cm in diameter up to 10 cm or more.
Most accrete around a nucleus of some sort, usually
a volcanic fragment but sometimes biological
remains.
The deposits were first described in detail in the
Challenger Reports. This work was co-authored by J.
Murray and A. Renard, who between them initiated
Table 1 Average abundances of elements in ferromanganese oxide deposits
366
D. S. Cronan, Royal School of Mines, London, UK
Copyright & 2001 Elsevier Ltd.
Introduction
Manganese nodules, together with micronodules and
encrustations, are ferromanganese oxide deposits
which contain variable amounts of other elements
(Table 1). They occur throughout the oceans, although the economically interesting varieties have a
much more restricted distribution. Manganese nodules are spherical to oblate in shape and range in size
from less than 1 cm in diameter up to 10 cm or more.
Most accrete around a nucleus of some sort, usually
a volcanic fragment but sometimes biological
remains.
The deposits were first described in detail in the
Challenger Reports. This work was co-authored by J.
Murray and A. Renard, who between them initiated
Table 1 Average abundances of elements in ferromanganese oxide deposits
366