The data presented in this report demonstrate significant improvements
in the ability to constrain trace element and Sr isotopic
concentrations in sediments overlying ridge-flank hydrothermal
systems. Improved sampling methods orchestrated by the Integrated
Ocean Drilling Program (i.e., advanced piston coring and
anoxic sample processing) enabled the collection of reactive pore
water species with minimal alteration and sampling artifacts.
Improved methods of high-resolution inductively coupled
plasma–mass spectrometry trace element analysis, including the
use of the 8-hydroxyquinoline functional group to extract and
preconcentrate rare earth elements and other trace metals, were
used to compile a data set of 28 trace element concentrations and
⁸⁷Sr/⁸⁶Sr ratios. From this extensive data set, we were able to increase
the current understanding of how redox-reactive species respond
to diagenic processes. Near-basement trends were used in
combination with the known composition of hydrothermal fluids
that exit Baby Bare Springs to asses our ability to predict basement
fluid compositions using sediment pore water profiles collected
by deep-sea drilling. The results show that prediction of basement
fluid composition is possible for many trace elements, provided
the near-basement concentration gradients are minimal. In order
to place the Ge/Si systematics in a broader context, pore water
and borehole fluid Ge and Si data are presented from additional
sites across the Juan de Fuca Ridge flank and from two additional
ridge-flank settings. These data show that Ge concentrations and
Ge/Si ratios are much higher in the basement fluids than in the
basal sediments because of increased mobilization of Ge relative
to Si within the basement hydrothermal reservoir. Solid-phase
sediment data are presented, highlighted by the occurrence of
Mn- and carbonate-rich layers