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Data report: carbon and oxygen isotopes of bulk sediments from the off-mound site, Hole U1318B1

Chizuru Takashima,2 Akihiro Kano,2 and Xianghui Li3


The first and only attempt to drill throughout a deepwater coral mound was carried out during Integrated Ocean Drilling Program Expedition 307. Along with Site U1317 at the summit of Challenger Mound, offshore Ireland, two reference sites were selected in order to construct the regional stratigraphic framework. Sediments from near-shelf Site U1318 are mainly composed of silty clay and sands of Miocene–Pleistocene age. We analyzed oxygen and carbon isotopic composition of the bulk sediments for the upper 90.5 m in order to understand the source of the carbonate fraction. δ13C values range from –3.15‰ to 1.20‰ (versus Vienna Peedee belemnite [VPDB]) and δ18O values range from –4.59‰ to 1.87‰ (versus VPDB). A distinct stratigraphic trend is that the Miocene sediments record higher δ18O values. In general, the carbonate fraction of Site U1318 sediments have much lower oxygen and higher carbon isotopic values than the mound sediments, and the oxygen values are similar to those of Cretaceous chalk.

1 Takashima, C., Kano, A., and Li, X., 2009. Data report: carbon and oxygen isotopes of bulk sediments from the off-mound site, Hole U1318B. In Ferdelman, T.G., Kano, A., Williams, T., Henriet, J.-P., and the Expedition 307 Scientists, Proc. IODP, 307: Washington, DC (Integrated Ocean Drilling Program Management International, Inc.). doi:10.2204/​iodp.proc.307.202.2009

2 Graduate School of Social and Cultural Studies, Kyushu University, Motooka 744, Fukuoka 819-0395, Japan. Correspondence author:

3 Department of Earth Science, State Key Laboratory for Mineral Deposits Research, Nanjing University, 22 Hankou Road, Nanjing, Jiangsu 210093, China.

Initial receipt: 7 June 2008
Acceptance: 27 May 2009
Publication: 15 July 2009
MS 307-202