X. Wen et al., INTERELEMENT RELATIONSHIPS IN FERROMANGANESE CRUSTS FROM THE CENTRAL PACIFIC-OCEAN - THEIR IMPLICATIONS FOR CRUST GENESIS, Marine geology, 136(3-4), 1997, pp. 277-297
The fine-scale chemical variations in ferromanganese (Fe-Mn) crusts fr
om the central Pacific Ocean were investigated using a variety of tech
niques in order to elucidate their genesis. Thirty-seven major, minor
and trace elements were determined by ICP-OES and ICP-MS in sub-sample
s collected at approximately 2 mm intervals throughout the crust seque
nces. An inverse relationship is observed between the logarithm of the
elemental distribution coefficients [log (C-Mn/C-SW)] and the mean re
sidence time (t(T)) of elements in seawater. These associations provid
e evidence supporting the strong link between seawater and Fe-Mn crust
chemistry. Results of factor analysis reveal that elements in crusts
can generally be partitioned into four major groups with selected elem
ents displaying associations with several groups. These statistical as
sociations are interpreted to represent hydrogenetic (Mn, Ni, Co, Cu,
Ce, Zn), biogenic (Ba, Zn, Cu, Pt, Fe), detrital (Al, Si, Fe) and carb
onate fluorapatite (Ca, P, REE) groups. A comparison between elemental
associations in fine-scale data from individual crust sequences and b
ulk compositional data from samples collected in separate locations re
veals very similar elemental associations. The similar elemental assoc
iations in bulk samples and in fine-scale subsamples from individual c
rusts are consistent with the notions that hydrogenetic crusts exhibit
no significant post-depositional remobilization of elements, and that
elemental distributions within crusts reflect the chemistry of oceani
c water during the period in which they accreted. Chemical paleotracks
are proposed based on factor scores derived from chemical variations
as a function of depth in individual crusts. Our results show that the
re is internal consistency between the chemical evolution, previously
proposed seamount paleotracks, and nanofossil biostratigraphy dating r
esults.