Steph, Silke; Tiedemann, Ralf; Groeneveld, Jeroen; Sturm, Arne; Nuernberg, Dirk (2006): Pliocene changes in tropical East Pacific upper ocean stratification; response to tropical gateways?. Texas A&M University, Ocean Drilling Program, College Station, TX, United States, In: Tiedemann, Ralf, Mix, Alan C., Blum, Peter, Abrantes, Fatima F., Benway, Heather, Cacho-Lascorz, Isabel, Chen, Min-Te, Delaney, Margaret L., Flores, Jose-Abel, Giosan, Liviu, Holbourn, Ann E., Irino, Tomohisa, Iwai, Masao, Joseph, Leah H., Kleiven, Helga F., Lamy, Frank, Lund, Steven P., Martinez, Philippe, McManus, Jerry F., Ninnemann, Ulysses S., Pisias, Nicklas G., Robinson, Rebecca S., Stoner, Joseph S., Sturm, Arne, Wara, Michael W., Wei, Wuchang, Proceedings of the Ocean Drilling Program; scientific results; Southeast Pacific paleoceanographic transects; covering Leg 202 of the cruises of the drilling vessel JOIDES Resolution; Valparaiso, Chile, to Balboa, Panama; Sites 1232-1242; 29 March-30 May 2002, 202, georefid:2007-051094

A combination of stable isotope records and Mg/Ca temperature estimates of four different planktonic foraminiferal species from Ocean Drilling Program Site 1241 allows differentiation between temperature and salinity changes in the tropical east Pacific (TEP) upper water column during the Pliocene ( approximately 5.7-2.1 Ma). The deviation of delta (super 18) O records and Mg/Ca temperature estimates from thermocline-dwelling planktonic foraminifers suggests that local changes in salinity exerted a much stronger control on Pliocene TEP upper ocean water mass signatures than previously assumed. The most pronounced Pliocene change in TEP upper ocean stratification was the shoaling of the thermocline from approximately 4.8 to 4.0 Ma that was possibly triggered by changes in the configuration of low-latitude ocean gateways. During this time interval, mixed-layer temperatures and salinities remained relatively constant in contrast to a pronounced temperature ( approximately 6 degrees C) and salinity decrease at the bottom of the photic zone. This change led to a new state in the thermal structure of the TEP, as the thermocline remained relatively shallow until approximately 2.1 Ma.
West: -86.2700 East: -86.2700 North: 5.5100 South: 5.5100
Expedition: 202
Site: 202-1241
Supplemental Information:
Includes appendix
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Provider: SEDIS Publication Catalogue
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