georefid:2003-014797SEDIS Publication Catalogue

ana.macario@awi.de

http://sedis.iodp.org/pub-catalogue/informationpointOfContact2011-06-23T00:00:00Zhttp://sedis.iodp.org/pub-catalogue/index.php?id=2003-0147972002-01-01publicationgeorefid:2003-014797Yang LihongChinese Academy of Sciences, South China Sea Institute of Oceanology, Guangzhou, ChinaauthorChen MuhongTongji University, ChinaauthorWang RujianauthorZhen FanauthorScience Press, Beijing, ChinapublisherdocumentHardcopyChinese Science Bulletin47 (17)1478-1483This note studies the Radiolarian fossil groups since 1.2 MaBP in ODP leg 184 site 1143, the southern South China Sea (SCS). The result shows that radiolarian abundance experienced a significant variation: before 0.9 MaBP it remained at the extremely low level, but increased with low extent between 0.9-0.65 Ma, which corresponded to the Mid-Pleistocene Transition stage, and it increased rapidly after 0.65 MaBP. During the whole process, the average abundance became higher and higher in each stage, and showed regularly periodic fluctuations. The obvious increase after 0.65 MaBP is inferred to result from the enhanced upwelling in this region, which was induced by the intensified monsoon circulation after the "Mid-Pleistocene Transition". An outstanding result of the spectral analyses is that a long oscillation of approximately 0.2 Ma cycle was found in the records of radiolarian abundance and complex diversity, which corresponds well to the result of other paleoceanographic indexes. This probably indicated a special cycle characteristic of paleoecological environment evolution in this area. In addition, all of the radiolarian indexes show an obvious boundary in about 0.47 MaBP, indicating the abrupt variation of the community structure and radiolarian abundance level before and after 0.47 MaBP. So we suppose that there existed a distinct change event of oceanic ecology environment during that period.completedQuaternary geologyCenozoicInvertebrataLeg 184microfossilsmiddle PleistoceneNorth PacificNorthwest PacificOcean Drilling ProgramODP Site 1143Pacific Oceanpaleo-oceanographypaleoecologypaleoenvironmentPleistoceneProtistaQuaternaryRadiolariareconstructionSouth China Seasouthern South China SeaWest Pacificurn:org.iodp:exp:184urnlargerWorkCitationcampaignurn:org.iodp:exp:184:site:1143urnlargerWorkCitationstudyurn:org.iodp:exp:184urnlargerWorkCitationcampaignEnglishgeoscientificInformation113.1707113.17079.21439.2143