Provenance of Colorless and Brown Volcanic Glass in Late Pleistocene Tephra Layers in the Western Philippine Sea

Tephra layers in the western Philippine Sea, characterized by abundant volcanic glass shards, may provide crucial evidence on the eruption history of volcanoes and tectonic evolution of the western Pacific. A 220-ka sediment core from the Benham Rise in the western Philippine Sea offers new insights into the provenance of four intercalated tephra layers (T1–T4, in chronological order) containing either colorless or brown glass shards. Relative to primitive mantle, all glass shards are enriched in large-ion lithophile elements, such as Rb, Cs, and Pb, and depleted in high field-strength elements, such as Th, Nb, and Ta, indicating a subduction-related origin. The colorless glass shards are characterized by high SiO2 (>78