Mg/Ca ratios of Cenozoic benthic foraminifera from the Indian and South Atlantic Ocean ...

• Main Authors: Billups, Katharina, Schrag, Daniel P
• Format: Article in Journal/Newspaper
• Language: English
• Published: PANGAEA 2003
• Subjects: Composite Core; Leg113; Leg121; Joides Resolution; Ocean Drilling Program ODP; South Atlantic Ocean; Southern Ocean; Weddell Sea
• Online Access: https://dx.doi.org/10.1594/pangaea.708305; https://doi.pangaea.de/10.1594/PANGAEA.708305

We investigate the evolution of Cenozoic climate and ice volume as evidenced by the oxygen isotopic composition of seawater (delta18Osw) derived from benthic foraminiferal Mg/Ca ratios to constrain the temperature effect contained in foraminiferal delta18O values. We have constructed two benthic foraminiferal Mg/Ca records from intermediate water depth sites (Ocean Drilling Program sites 757 and 689 from the subtropical Indian Ocean and the Weddell Sea, respectively). Together with the previously published composite record of Lear et al. (2002, doi:10.1126/science.287.5451.269) and the Neogene record from the Southern Ocean of Billups and Schrag (2002, doi:10.1029/2000PA000567), we obtain three, almost complete representations of the delta18Osw for the past 52 Myr. We discuss the sensitivity of early Cenozoic Mg/Ca-derived paleotemperatures (and hence the delta18Osw) to assumptions about seawater Mg/Ca ratios. We find that during the middle Eocene (~ 49-40 Ma), modern seawater ratios yield Mg/Ca-derived ... : Supplement to: Billups, Katharina; Schrag, Daniel P (2003): Application of benthic foraminiferal Mg/Ca ratios to questions of Cenozoic climate change. Earth and Planetary Science Letters, 209(1-2), 181-195 ...