Geochemical data on the 2005 lava flow of Barren Island volcano, Andaman Sea

In this paper are presented new geochemical and isotopic data on the lava flows emitted in the 2005 from Barren (Andaman Sea, Indian Ocean), a subduction-related volcano representing the only active volcanic system in the Indian Subcontinent; the volcano, currently in the fumarolic stage, witnessed several eruptions during pre-historic and historic times. The 2005 Barren volcanics display low-K basaltic composition; chondrite normalised REE patterns show very moderate fractionation (La/Yb = 1.31-1.48); incompatible element patterns are those typical of island-arc basic rocks and are similar to those of some older Barren rocks; they are characterised by moderate fractionation, negative anomalies of Ta, Nb, P and Ti and slight enrichment of Th, K and Sr. Measured Sr and Nd isotopic ratios display small variation (87Sr/86Sr = 0.703996-0.704062; 143Nd/144Nd = 0.512899-0.512919) and fall in the range of the existing data for the Barren rocks. Petrographic and geochemical evidence indicates for the Barren magmas a complex petrogenetic history. The 2005 lava flows show a strong similarity with the previously erupted volcanics, suggesting that similar genetic and evolutionary processes were active along all the history of the Barren Volcano.