Depositional history of the SULU Sea from ODP 768, 769 and 771
Abstract
Holes were drilled at three sites in the Sulu Sea on Ocean Drilling Program Leg 124. Site 768 lie in the deeper part of the SE sub-basin and Sites 769 and 771 lies on the flanks of the Cagayan ridge. The results indicate that the Sulu Basin originated in the late early Miocene (c.18.8 Ma) in a backarc setting. The Cagayan Ridge was a site of early to early middle Miocene arc volcanism with the deposition of a thick sequence of andesitic to basaltic volcaniclastic deposits. In the basin center an early Miocene pelagic sequence is interrupted by a thick unit of royoltic to dacitic pyroclastic flows. Middle to late Miocene sedimentatin is more continental in character with thick quartz-rich turbidites in the basin center. Only the hemipelagic claystone related to these terrigenous turbidites were deposited on the Cagayan Ridge. A decrease in the supply of clastic detritus from arc and continental sources and a change in the level of the carbonate compensation depth in the upper Pliocene resulted in pelagic carbonate deposition throughout the late Pliocene and Pleistocene.
- Publication:
-
Geophysical Research Letters
- Pub Date:
- October 1990
- DOI:
- 10.1029/90GL01577
- Bibcode:
- 1990GeoRL..17.2065N
- Keywords:
-
- Oceanography: General: Paleoceanography;
- Information Related to Geographic Region: Pacific Ocean;
- Marine Geology and Geophysics: General or miscellaneous;
- Oceanography: General: Marginal and semienclosed seas;
- Tectonophysics: Plate boundary structures and processes;
- Information Related to Geologic Time: Cenozoic