Climate, Sea Level and Tectonic Controls on Sediment Discharge From
1 Climate, Sea Level and Tectonic Controls on Sediment Discharge from 2 the Sepik River, Papua New Guinea during the Mid- to Late Pleistocene 3 Aiello, I.W.1, Bova, S.C. 2, Holbourn, A.E. 3, Kulhanek, D.K.4, Ravelo, A.C.5 , and Rosenthal, Y.2 4 1 Moss Landing Marine Laboratories, 8272 Moss Landing Rd., Moss Landing, CA 95039 5 2Department of Marine and Coastal Sciences Rutgers, 71 Dudley Road, New Brunswick NJ 8521 6 3Institute of Geosciences, Christian-Albrechts-Universität zu Kiel, Ludewig-Meyn-Strasse 14, Kiel 7 24118, Germany 8 4International Ocean Discovery Program, 1000 Discovery Drive, College Station, TX 77845, USA 9 5Ocean Sciences Department, University of California, Santa Cruz, 1156 High Street, Santa Cruz CA 10 95064 11 Abstract 12 Amongst the rivers draining the mountainous islands of the Indonesian Archipelago, the Sepik River 13 of Papua New Guinea is the largest contributor of solute and particulate material to the world ocean. Sites 14 U1484 and U1485, drilled during International Ocean Discovery Program (IODP) Expedition 363 provide 15 a continuous, ~555 kyr long, high-resolution record of mainly siliciclastic slope sedimentation on the 16 northern continental margin of PNG, just offshore the mouth of the Sepik River. Sedimentological 17 analysis, based on a combination of smear slide petrography, particle size analysis, high-resolution 18 physical properties track data and visual core description, offers an unprecedented opportunity to 19 investigate the evolution of this major tropical river throughout changing climate and sea-level conditions 20 during the mid- to late Pleistocene. The Sites U1484 and U1485 sediment records exhibit a dramatic 21 lithologic change at ~ 370 ka: the oldest deposits are dominated by pelagic mud, suggesting that the 22 coarser-grained terrigenous discharge from rivers draining the New Guinea Highlands (including a 23 “proto” Sepik River) was captured before reaching the ocean, when the Sepik River basin was an 1 24 epicontinental sea.
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