Geochemistry and effect of oxidation state of iron at DSDP Leg 69 Holes

These analyses are displayed using a three-dimensional graphical method. Several alteration minerals have been identified, of which saponites are by far the most common.

In situ alteration of basalt glass has produced montmorillonite-like minerals rich in the less-mobile elements such as Al and Ti. Talc-like minerals commonly replace olivine and act as fillings to vesicles. Three other alteration minerals have been recognized chemically, rich in Na and Ca, but these are presently unidentified.