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@Article{CrivellariCKHPZZSMHAOM:2018:InAmFr,
               author = "Crivellari, Stefano and Chiessi, Cristiano Mazur and Kuhnert, 
                         Henning and H{\"a}ggi, Christoph and Portilho-Ramos, Rodrigo da 
                         Costa and Zeng, Jing-Ying and Zhang, Yancheng and Schefuß, Enno 
                         and Mollenhauer, Gesine and Hefter, Jens and Alexandre, Felipe and 
                         Oliveira, Gilvan Sampaio de and Mulitza, Stefan",
          affiliation = "{Universidade Federal de S{\~a}o Paulo (UNIFESP)} and 
                         {Universidade de S{\~a}o Paulo (USP)} and {University of Bremen} 
                         and {University of Bremen} and {Universidade Federal de S{\~a}o 
                         Paulo (UNIFESP)} and {University of Bremen} and {University of 
                         Bremen} and {University of Bremen} and {Alfred Wegener Institute 
                         for Polar and Marine Research} and {Alfred Wegener Institute for 
                         Polar and Marine Research} and {Instituto Nacional de Pesquisas 
                         Espaciais (INPE)} and {Instituto Nacional de Pesquisas Espaciais 
                         (INPE)} and {University of Bremen}",
                title = "Increased Amazon freshwater discharge during late Heinrich Stadial 
                         1",
              journal = "Quaternary Science Reviews",
                 year = "2018",
               volume = "181",
                pages = "144--155",
                month = "Feb.",
             keywords = "Heinrich Stadial 1, Amazon Basin, Continental precipitation, 
                         Planktonic foraminifera, Lipid biomarkers.",
             abstract = "The temporal succession of changes in Amazonian hydroclimate 
                         during Heinrich Stadial 1 (HS1) (ca. 1814.7 cal ka BP) is 
                         currently poorly resolved. Here we present HS1 records based on 
                         isotope, inorganic and organic geochemistry from a marine sediment 
                         core influenced by the Amazon River discharge. Our records offer a 
                         detailed reconstruction of the changes in Amazonian hydroclimate 
                         during HS1, integrated over the basin. We reconstructed surface 
                         water hydrography using stable oxygen isotopes (\δ18O) and 
                         Mg/Ca-derived paleotemperatures from the planktonic foraminifera 
                         Globigerinoides ruber, as well as salinity changes based on stable 
                         hydrogen isotope (\δD) of palmitic acid. We also analyzed 
                         branched and isoprenoid tetraether concentrations, and compared 
                         them to existing bulk sediment ln(Fe/Ca) data and vegetation 
                         reconstruction based on stable carbon isotopes from n-alkanes, in 
                         order to understand the relationship between continental 
                         precipitation, vegetation and sediment production. Our results 
                         indicate a two-phased HS1 (HS1a and HS1b). During HS1a (1816.9 cal 
                         ka BP), a first sudden increase of sea surface temperatures (SST) 
                         in the western equatorial Atlantic correlated with the slowdown of 
                         the Atlantic Meridional Overturning Circulation (AMOC) and the 
                         associated southern hemisphere warming phase of the bipolar 
                         seesaw. This phase was also characterized by an increased delivery 
                         of terrestrial material. During HS1b (16.914.8 cal ka BP), a 
                         decrease in terrestrial input was, however, associated with a 
                         marked decline of seawater \δ18O and palmitic acid 
                         \δD. Both isotopic proxies independently indicate a drop in 
                         sea surface salinity (SSS). A number of records under the 
                         influence of the North Brazil Current, in contrast, indicate 
                         increases in SST and SSS resulting from a weakened AMOC during 
                         HS1. Our records thus suggest that the expected increase in SSS 
                         due to the AMOC slowdown was overridden by a two-phased positive 
                         precipitation anomaly in Amazonian hydroclimate.",
                  doi = "10.1016/j.quascirev.2017.12.005",
                  url = "http://dx.doi.org/10.1016/j.quascirev.2017.12.005",
                 issn = "0277-3791",
             language = "en",
           targetfile = "crivellari_increased.pdf",
        urlaccessdate = "24 nov. 2020"
}


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