摘要：AbstractTest geochemistry of planktonic foraminifera is an indispensable tool in reconstructing past ocean hydrological changes. It is essential to investigate region-specific implications of test geochemistry, although those established from other regions can be broadly applied. In this study, characteristics ofδ18O and Mg/Ca from tests of four planktonic foraminiferal species,Globigerinoides rubersensu stricto (s.s.),Globigerinoides sacculifer,Pulleniatina obliquiloculataandNeogloboquadrina dutertrei,from 60 core-top sediment samples retrieved from the Indonesian Throughflow (ITF) region were studied. These geochemical data were compared with modern hydrographic profiles in order to assess their relations and to investigate potential implications of test geochemical parameters in reconstructing past oceanographic change in the ITF region. Calcification depths of these four species were first estimated based on comparison between measured testδ18O and predicted calciteδ18O that was calculated from modern temperature and salinity. The results indicate thatG. rubers.s. andG. sacculifercalcify within the mixed-layer at 0–50 m and 20–75 m, respectively, whereasP. obliquiloculataandN. dutertreicalcify within the thermocline at around 75 to 125 m. A combined study of excess Mg/Ca (difference between measured and predicted Mg/Ca) and salinity suggests that salinity exerts a negligible impact on test Mg/Ca of these foraminiferal species in the ITF region. Comparison of test Mg/Ca-derived temperatures with temperature profiles of the upper 200 m of the water column from the seas of the ITF region also indicate calcification depths of these species, which match well with the above estimations using testδ18O. It further indicates thatG. sacculifermay be more sensitive in reflecting changes in the depth of the mixed-layer, highlighting a potential use of Mg/Ca temperature difference betweenG. rubers.s. andG. sacculiferin reconstructing the depth of the mixed-layer in the ITF region.Graphical abstractDisplay OmittedHighlights•Geochemical parameters of planktonic foraminiferal tests from the Indonesian Throughflow region as paleoceanographic proxies.•Calcification depths ofG. rubers.sand G. sacculiferare 0–50 m and 20–75 m, respectively.•Calcification depths ofP. obliquiloculataandN. dutertreiare 75–125 m.•Negligible salinity effect on Mg/Ca ratios of planktonic foraminiferal tests.•Mg/Ca temperature difference betweenG. rubers.s andG. sacculiferis a potential mixed-layer depth proxy.
关键词：KeywordsenTest geochemistryMulti-speciesPlanktonic foraminiferaCore-top sedimentsIndonesian Throughflow region
