Geochemical Journal, Vol. 12, pp. 229 to 243, 1978
229
The distribution of rare earth, precious metal
and other trace elements in Recent and
fossil deep-sea manganese nodules
G. P. GLASBY,1 R. R. KEAYS,2 and P. C. RANKIN3
New Zealand Oceanographic Institute, D.S.I.R., P.O. Box 12-346, Wellington, New Zealand,1
Department of Geology, University of Melbourne, Victoria, Australia,2 and
Soil Bureau, D.S.I.R., Lower Hutt, New Zealand.3
(Received March 1, 1978; accepted in revised form August 22, 1978)
Four deep-sea manganese nodules and one fossil nodule from Timor have been analysed for 45
elements (major elements, rare earths and precious metals) by X-ray fluorescence, spark source mass
spectrometry and neutron activation analysis. Co-existing sediments from two nodule sites in the Southwestern Pacific Basin have also been analysed. Differences in nodule composition are apparent, particularly
for the Timor nodule. The trace metal compositions of this nodule, however, reveals it to be a typical
deep-sea nodule, although some element redistribution has clearly taken place since exposure of the nodule
on land. The distribution of a number of elements including TI, Ir, Pd, Au and the rare earth elements
between deep-sea nodules and their associated sediments appears to be dependent on a number of
factors including the major element composition of the nodule (e.g. dilution by the silicate phase of the
nodule), the differing stability of various element complexes in seawater, and the influence of differences
in redox states on complex stability. Au and Si, on the other hand, are positively correlated in nodules and
sediments possibly because they have a common source, either submarine detritus or basalt-seawater
interaction. The rare earth contents of the sediments from the N.E. sector of the Southwestern Pacific
Basin are high compared with previous determinations of rare earths in marine sediments and show no
evidence of Ce depletion relative to La on a shale-normalised basis. These high contents reflect the well
oxidised conditions and low sedimentation rates of this environment.