ABSTRACT: Provenance and Sedimentary Basin Evolution in the Sulu and Celebes Seas
Gary J. Nichols
The sites drilled on ODP Leg 124, two in the Celebes Sea and three in the Sulu Sea, provide a sedimentary record of the history of these two marginal basins and the adjacent terranes of Borneo and the Philippines. The Celebes Sea was an area of deep-water pelagic sedimentation until the early Miocene, the absence of clastic detritus indicating that the basin was distant (or sheltered) from any land areas. Following the formation of the Sulu Sea basin in the late early Miocene, middle to late Miocene sedimentation in the two basins was dominated by terrigenous detritus. Turbidites of well-rounded quartz-rich sand and silt with minor amounts of feldspar, rock fragments, and benthic foraminifers were deposited in the deeper parts of both basins. Abundant plant debris and coa clasts in the thicker turbidites suggest that the
detritus was reworked from a shallow-marine source, probably a vegetated delta or coastal plain; the continental basement of Borneo is the most likely provenance area, but the continental fragments of the southern Philippines are also a possible source. Terrigenous turbidite deposition waned in both basins after a peak in the late middle Miocene. This cessation, or diversion, of continental clastic supply may be attributed to tectonic events at the basin margins. Late Miocene to Holocene sediment in the Celebes Sea is mainly claystone with thin ash beds and turbidites of shallower bioclastic debris; the provenance of detritus in the Sulu Sea is similar, but Quaternary sedimentation occurred above the CCD.
AAPG Search and Discovery Article #90097©1990 Fifth Circum-Pacific Energy and Mineral Resources Conference, Honolulu, Hawaii, July 29-August 3, 1990