This study investigates
the 18O
of pore waters from Sites 1003 through 1007, drilled along the western margin of
the Great Bahama Bank during Leg 166 of the Ocean Drilling Program. These pore
waters generally show a positive correlation between
18O
and the concentration of chloride. The exception to this trend is Site 1006,
where the pore waters exhibit nonlinear behavior with respect to chloride. The
correlation between the concentration of Cl- and
18O
at most of the sites appears to be a coincidence because although the increase
in Cl- is
a result of diffusion from an underlying source, the increases in
18O
result from the recrystallization of metastable carbonates in the presence of a
geothermal gradient. The difference in behavior in the
18O
of the pore water at Site 1006 is probably a result of the relative reduced rate
of carbonate recrystallization at this site. The
18O
of the pore waters in the upper portion of the cores shows a pattern similar to
the concentration of chloride in that there is an interval of 30-50 m in which
neither the
18O
nor the concentration of Cl- changes. This interval is consistent
with either an interval of very rapid deposition of sediment or the advection of
fluid through the platform. Both the
18O
and the concentration of Cl- increase toward the platform, suggesting
an input of saline and isotopically heavy water from the platform surface.
1Swart,
P.K., Eberli, G.P., Malone, M.J., and Sarg, J.F. (Eds.), 2000. Proc. ODP, Sci.
Results, 166 [Online]. Available from World Wide Web: <http://www-odp.tamu.edu/publications/166_SR/1166TOC.HTM>.
[Cited YYYY-MM-DD]
2Division
of Marine Geology and Geophysics, University of Miami, 4600 Ricken-backer
Causeway, Miami FL 33149, USA. pswart@rsmas.miami.edu
Date of initial
receipt: 13 August 1998
Date of acceptance: 6 April 1999
Ms 166SR-130