Geological Setting of the Celebes and Sulu Seas

Abstract

The Sulu and Celebes Seas lie to the southeast of the South China Sea, within a complex geodynamic environment marked by active arc-arc or arc-continent collision zones, subduction zones, and long strike-slip fault zones. Prior to Leg 124, neither the ages nor the mode of formation of these basins were clear. The basins are located near the zone of complex junction be- tween the Pacific, Indian Ocean, and Philippine Sea plates (Fig. 1). They may have been related to the history of one of these plates prior to collision or be the remnants of a subducted ocean that previously extended between these major plates (the Mo- lucca Sea or neo-Tethys Ocean). Alternatively, they may have formed by back-arc spreading processes or, as in the case of the South China Sea, as a result of continental rifting unrelated to arc activity.