Petrogenesis of subduction-related lavas from the southern Tonga arc

We present new whole-rock geochemical data for volcanic rocks dredged from active submarine volcanoes TA15, TA16, and TA19 that mark the southern part of the Tonga Arc near Ata island. The lava samples show a wide range of compositions from basalt to dacite within the low-K tholeiitic series, and geochemical data indicate fractional crystallization of olivine, orthopyroxene, clinopyroxene, and plagioclase. The origin of magmas in the southern...