georefid:2004-011521georefid:2004-011510SEDIS Publication Catalogueana.macario@awi.dehttp://sedis.iodp.org/pub-catalogue/informationpointOfContact2011-06-23T00:00:00Zhttp://sedis.iodp.org/pub-catalogue/index.php?id=10.2973/odp.proc.sr.186.116.2003<gco:CharacterString>Variations in the accumulation of marine organic matter and carbonates at Leg 186 sites</gco:CharacterString>2003-01-01publicationgeorefid:2004-011521doi:10.2973/odp.proc.sr.186.116.2003Mora, GermanIowa State University, Department of Geological and Atmospheric Sciences, Ames, IA, United StatesauthorTexas A&M University, Ocean Drilling Program, College Station, TX, United StatespublisherdocumentDigitalIn: Suyehiro, Kiyoshi, Sacks, I. Selwyn, Acton, Gary D., Acierno, Michael J., Araki, Eiichiro, Ask, Maria V. S., Ikeda, Akihiro, Kanamatsu, Toshiya, Kim, Gil Young, Li, Jingfen, Linde, Alan T., McWhorter, Paul N., Mora, German, Najman, Yanina M. R., Niitsuma, Nobuaki, Pandit, Benoy K., Roller, Sybille, Saito, Saneatsu, Sakamoto, Tatsuhiko, Shinohara, Masanao, Sun, Yue-Feng, Proceedings of the Ocean Drilling Program, scientific results, Western Pacific geophysical observatories; covering Leg 186 of the cruises of drilling vessel JOIDES Resolution; Yokohama, Japan, to Yokohama, Japan; sites 1150 and 1151, 14 June-14 August 1999186Past changes in sea-surface productivity in the Oyashio Current are evaluated on the basis of abundances of biological constituents in sediments from Leg 186 sites. Organic carbon contents at Sites 1150 and 1151 are moderate (0.5 to 1.5 wt%) and have an algal origin as indicated by low C/N ratios (<10) and by carbon isotopic compositions ranging from -23.4 to -21.3. A decreasing trend in organic carbon contents, carbon isotope ratios, and C/N ratios occurs with depth at both sites, probably as a consequence of diagenetic degradation of organic matter. Mass accumulation rates (MARs) determined for organic carbon and carbonates at Sites 1150 and 1151 show an abrupt increase between approximately 5 and 7 Ma. Similar results have been reported for sites in the Indian Ocean and the Pacific Ocean for the same time interval. As it has been previously suggested, the observed increase in MAR for both carbonate and organic carbon at Leg 186 sites probably resulted from augmented nutrient supply either from continental sources or from a more vigorous ocean circulation.completedStratigraphyGeochemistry of rocks, soils, and sedimentscarboncarbonatesCenozoicchemical ratioscurrentsdepositional environmentdiagenesisgeochemistryJapan TrenchLeg 186marine environmentmarine sedimentsMioceneNeogenenitrogenNorth PacificNorthwest Pacificocean currentsOcean Drilling Programocean floorsODP Site 1150ODP Site 1151organic compoundsOyashio CurrentPacific Oceanpaleo-oceanographysedimentationsedimentation ratessedimentsTertiaryupper MiocenevariationsWest Pacificurn:org.iodp:exp:186urnlargerWorkCitationcampaignurn:org.iodp:exp:186:site:1150urnlargerWorkCitationstudyurn:org.iodp:exp:186urnlargerWorkCitationcampaignurn:org.iodp:exp:186:site:1151urnlargerWorkCitationstudyurn:org.iodp:exp:186urnlargerWorkCitationcampaignEnglishgeoscientificInformation143.2000143.200038.450039.1100Available only on CD-ROM in PDF format and on the Web in PDF or HTMLapplication/pdfunknownSEDIS Publication Catalogueana.macario@awi.dehttp://sedis.iodp.org/pub-catalogue/informationpointOfContacthttp://www-odp.tamu.edu/publications/186_SR/VOLUME/CHAPTERS/103.PDFdownload