History of the Celebes Sea Basin based on its stratigraphic and sedimentological record |
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| Institution: | 1. Southeast Asia Research Group, Department of Geology, Royal Holloway, University of London, Egham, Surrey, TW20 0EX, UK;1. Department of Geology and Geophysics, University of Hawai‘i at Mānoa, 1680 East–West Road, Honolulu, HI 96822, USA;2. Research and Development Center for Earthquake and Tsunami, Japan Agency for Marine–Earth Science and Technology, 3173-25 Showa-machi, Kanazawa-ku, Yokohama 236-0001, Japan;1. School of Earth Sciences, East China University of Technology, Nanchang 330013, China;2. State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, CAS, Nanjing 210008, China;3. Department of Paleobiology, MRC-121, Smithsonian Institution, Washington, DC 20013, USA |
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| Abstract: | The stratigraphic and sedimentary history of the Celebes Sea Basin provides the basis for a tectonic model for its evolution which is consistent with new regional plate reconstructions. Cores drilled on Leg 124 of the Ocean Drilling Program (sites 767 and 770) form a stratigraphic record from the basement to the sea floor in just under 800 metres of sedimentary succession. The basement itself is basalt with a strong MORB affinity. Radiolaria in pelagic mudstones at the base of the succession indicate a late middle Eocene age. A very condensed pelagic sequence (90 m in 20 Ma) suggests a setting which was distal from sources of terrigenous clastics and volcaniclastics and below the CCD. These characteristics are similar to the West Philippine Sea Basin (drilled on DSDP Legs 31 and 59), which also has oceanic basement, dated at 44–42 Ma, and Paleogene pelagic strata. These data are therefore consistent with any plate reconstruction model which has these two basins forming as part of the same ocean basin.During the Miocene quartz-rich sandy turbidites were deposited in the Celebes Sea Basin. This influx of terrigenous clastics occurred for a brief period in middle to late Miocene times (c. 10 Ma). The nearest large continental landmass which could have acted as the source of this mature siliciclastic detritus was the island of Borneo, and the onset of this clastic supply may be related to uplift caused by collision events on the island. Cessation of terrigenous clastic supply to the basin centre occurred as southward subduction of the underlying oceanic crust beneath the northern arm of Sulawesi began. It is speculated that the development of a trench along the southern margin of the basin acted as a trap for detritus coming from Borneo, diverting material from the basin centre. |
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