Figure AF1. The systematic relationship between the ratio of Zr to TiO2 and anhydrous SiO2 content for Pual Ridge glassy lavas (unpublished CSIRO data) enables assessment of the parentage for altered rocks cored at PACMANUS during Leg 193, on the assumption that Zr and Ti behave in immobile fashion during hydrothermal alteration. Plot uses XRF data only.