Figure F14. A–D. Anhydrous major element compositions of hydrothermally altered gabbronorite samples from Site 1268, plotted in terms of oxide mole fractions (speciation as for Fig. F13). Calcic amphibole end-members are tremolite/actinolite, hornblende, edenite, pargasite, and tschermakite. Chlorite end-member is clinochlore. Bold triangles in panels B, C, and D enclose possible gabbronorite assemblages with calcic plagioclase. Light gray arrows show trend of increasing alteration and metasomatism for Site 1268 gabbronorites. The freshest samples have compositions similar to igneous gabbronorites, whereas the most altered samples approach the composition of talc-chlorite-quartz mixtures, in accord with the observed alteration assemblage. Cpx = clinopyroxene, opx = orthopyroxene, serp = serpentinite.