Abstract
The giant piston core MD01-2387 taken from the eastern Celebes Sea basin pro vides 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 com posed of volcanic minerals and glassy particles. The compositional character is tics of crystal enriched tephra layers and the 87Sr/86Sr 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 sys tem, the Sangehi Arc and the Halmahera Arc. The up ward de crease 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 be came extinct at ca. 151 ka, which is much younger than what reported previously by onland investigations.
Highlights
Discrete marine tephra layers represent instant ash fallout deposits because volcanic materials sink more rapidly than other pelagic or hemipelagic particles (Wiesner et al 1995)
A total of 65 discrete tephra layers were recognized by microscopic examination
Assuming that the paleo-wind patterns around the CSB are similar to the present ones, all the Quaternary volcanic provinces surrounding the CSB can be considered to be potential sources of the marine tephra layers found in Core MD01-2387
Summary
Discrete marine tephra layers represent instant ash fallout deposits because volcanic materials sink more rapidly than other pelagic or hemipelagic particles (Wiesner et al 1995). Over time, stratified tephra layers preserved in deep-sea basins are better protected against external erosive forces than those preserved on land. The deep-sea tephrostratigraphic record can provide a complete record of large volcanic eruptions in a particular area. Marine microfossils in the intervenient intervals provide biostratigraphic correlation markers by which the record can be well tied to global chronology. In 2001, a giant piston core for IMAGES (International Marine Global Changes Study) at Site MD01-2387 was raised from the Celebes Sea Basin (CSB) at 4°47.27’N latitude and 123°30.09’E longitude (Fig. 1) and is very close to the ODP Site 767B Volcanism is still active on some of the islands (Simkin and Siebert 1994)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
