Characteristics of trace elments, rare-earth elements, and Sr and Nd isotopic ratios of Amakusa-Shimoshima basalts, Southern Kyushu

Gesu-jima basalt at 10Ma and Gongen-yama basalt at 7Ma erupted in Amakusa-Shimoshima, Southern Kyushu. Major, trace and rare-earth elements, and Sr and Nd isotopic ratios were analyzed from these basalts. Gesu-jima basalt shows within-plate-type signature. Gongen-yama basalt has a slight depletion in Nb. Gesu-jima basalt might be derived from fertile mantle. However, source mantle of Gongen-yama basalt was probably generated by mixing between a large amount of fertile mantle and a small amount of depleted mantle weakly metasomatized by subduction component.