School of Engineering and Science - Jacobs University

ulk, open ocean seawater tended to more positive Є Nd values as suggested by the
Pietersburg IF data.
Finally, the suggestion that iron-formations may have precipitated as Fe(II)
minerals is worthy of future study. Many unanswered questions remain regarding this
hypothesis, ranging from the primary mineralogy of such a precipitate to its conversion
to the Fe(III) mineral phases that dominate oxide facies IFs. One intriguing aspect of
such a model regards the REY patterns of many Archean IFs. As discussed in the
Introduction to this thesis, Fe oxy-hydroxides that precipitate from, and are in
equilibrium with, modern seawater, display REY patterns distinctly different from
ambient seawater. The seawater-like REY patterns observed in many Archean-
Paleoproterozoic IFs have been attributed to quantitative scavenging of the REY from
ancient seawater during the process(es) that produced IFs. If, however, the primary IF
precipitate was predominantly composed of Fe(II) mineral phases, then different
mechanisms for incorporating the REY into IFs may have operated, and further
examination of this potential process is warranted.
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