The alteration of subseafloor volcanic glass from three locations is qualitatively attributed to biological
(biotic) or chemical (abiotic) reactions on the basis of microscopic morphology of the boundary between
the unaltered and altered glass. Eleven-element composition of fresh basalt glass (sideromelane) and its
alteration products were determined by electron microprobe....
The Hawaii Scientific Drilling Program (HSDP) cored and recovered igneous rock from the surface to a
depth of 3109 m near Hilo, Hawaii. Much of the deeper parts of the hole is composed of hyaloclastite
(fractured basalt glass that has been cemented in situ with secondary minerals). Some hyaloclastite units...