Late Quaternary Explosive Volcanic Activities of the Mindanao-Molucca Sea Collision Zone in the Western Pacific as Inferred from Marine Tephrostratigraphy in the Celebes Sea

Abstract

The gi ant pis ton core MD01-2387 taken from the east ern Celebes Sea ba sin pro vides a ma rine tephrostratigraphy with high res o lu tion for in fer ring ex plo sive vol ca nism in the area sur round ing the ba sin for the past 350 kyr. The se quence con tains 65 tephra lay ers com posed of vol ca nic min er als and glassy par ti cles. The compositional char ac ter is tics of crys tal en riched tephra lay ers and the 87 Sr/ 86 Sr of the glass par ti cles (0.7039 to 0.7042) sug gest that these ashes were re leased by the vol ca noes in the Mindanao-Molucca Sea col li sion zone, in clud ing the south Phil ip pine Arc sys tem, the Sangehi Arc and the Halmahera Arc. The up ward de crease of tephra lay ers in this core in di cates a de clin ing trend of ex plo sive vol ca nic ac tiv ity of this col li sion zone, par tic u larly, af ter ca. 180 ka in the late Mid dle Pleis to cene. This re cord also sug gests that the shoshonitic vol ca nism in Cen tral Mindanao be came ex tinct at ca. 151 ka, which is much younger than what reported previously by onland investigations.

Timing, magnitude and geochemistry of major Southeast Asian volcanic eruptions: identifying tephrochronologic markers

“…(g–h) Blue symbols are average compositions of individual marine tephra layers in cores from around the Philippines, studied by Ku et al . (, ), Desprairies et al . () and Pouclet et al .…”

“…Tephra in marine cores around the Philippines were studied to reconstruct the long‐term volcanic and geodynamic activity of various arc segments (Desprairies et al ., ; Pouclet et al ., ; Ku et al ., , b). In the Celebes Sea, 49 tephra layers younger than 338 ka were found in core MD01‐2387 (Fig.…”

“…In the Celebes Sea, 49 tephra layers younger than 338 ka were found in core MD01‐2387 (Fig. ), and they are believed to have sources in Mindanao, Sangihe and Halmahera principally (Ku et al ., ). In the Celebes and Sulu seas, 32 tephra layers of age Pleistocene to present in cores ODP‐ 767, 768, 769 and 770 were studied by Pouclet et al .…”

“…4b of Smith et al, 2011). The main drawback of using mineralogy or mineral compositions to identify the source of distal tephra layers could be the lack of phenocrysts, as they sediment earlier or closer to the source given their greater density compared with glass shards (Bitschene and Schmincke, 1990;Ku et al, 2009a). However, magnetites and ilmenites are often small and present in the groundmass making them highly valuable, in association with matrix glass major and trace element geochemistry, for identifying the source volcano and eruption.…”

“…In the Celebes Sea, 49 tephra layers younger than 338 ka were found in core MD01-2387 (Fig. 1), and they are believed to have sources in Mindanao, Sangihe and Halmahera principally (Ku et al, 2009a). In the Celebes and Sulu seas, 32 tephra layers of age Pleistocene to present in cores ODP-767, 768, 769 and 770 were studied by Pouclet et al (1991) and another 44 tephra layers were studied by Desprairies et al (1991) and their sources are believed to be in Mindanao and Visayas (Negros) mainly.…”