Water percolation in the oceanic crust?



There is growing evidence that water percolates throughout the crust at an oceanic spreading center. Perhaps it is time to think about how to use the deep ocean floor drill holes planned by the International Program for Ocean Drilling to test this hypothesis.

Interpretations of heat flow data and of the surface sediment composition near mid-ocean ridge crests are beginning to suggest that water percolates to substantial depths in the fresh oceanic crust. The heavy metal content of the uppermost sediment increases as the ridge crest is approached and peaks spectacularly if it is expressed as a ratio to alumina concentration [Piper, 1973]. The purpose of using alumina as the inorganic invariant is to remove the effect of dilution by biogenic carbonate and silica, for this introduces a large scatter into the absolute concentrations of inorganically deposited material.