Academia Sinica, Taiwan

The giant piston core MD01-2387 taken from the eastern Celebes Sea basin provides a marine tephrostratigraphy with high resolution for inferring explosive volcanism in the area surrounding the basin for the past 350 kyr. The sequence contains 65 tephra layers composed of volcanic minerals and glassy particles. The compositional characteristics of crystal enriched tephra layers and the (super 87) Sr/ (super 86) Sr of the glass particles (0.7039 to 0.7042) suggest that these ashes were released by the volcanoes in the Mindanao-Molucca Sea collision zone, including the south Philippine Arc system, the Sangehi Arc and the Halmahera Arc. The upward decrease of tephra layers in this core indicates a declining trend of explosive volcanic activity of this collision zone, particularly, after ca. 180 ka in the late Middle Pleistocene. This record also suggests that the shoshonitic volcanism in Central Mindanao became extinct at ca. 151 ka, which is much younger than what reported previously by onland investigations.