The iron sulfides constitute a diverse group of solids and dissolved complexes many of which play key roles in marine systems.The group is particularly complex in the lower temperature environments characterizing much of the Earth's surface where a number of metastable phases become significant in biogeochemical processes.At least seven different solids consisting only of iron and sulfur are known to occur naturally at these temperatures(Table 1).At higher temperatures,the chemistry appears to be simpler although this may be partly a consequence of the experimental difficulties of probing supercritical and often salt-rich aque ous fluids.Certainly the number of iron sulfide products,as seen in the geological record,appears more restricted.This review is concerned with the complex lower temperature chemistry of iron sulfides,which is more directly related to marine systems.There is an interface between this lower temperature regime and the higher temperature regime in the deep ocean hydrothermal vents,where iron sulfide fluids debouch into the deep oceans at temperatures up to 400degC.We dip our feet tentatively into these waters at the end of this review.
展开▼
