B- and O-isotope and Mg/Ca ratios of planktonic foraminifera and estimates of salinity, alkalinity and pCO2 for ODP Hole 108-668B (Table 1)

• Main Authors: Hönisch, Bärbel, Hemming, N Gary, Archer, David E, Siddall, Mark, McManus, Jerry F
• Format: Dataset
• Language: English
• Published: PANGAEA 2009
• Subjects: 108-668B; AGE; Alkalinity; total; Calculated; Calculated from Mg/Ca ratios; Comment; DRILL; Drilling/drill rig; DSDP/ODP/IODP sample designation; Error; absolute; Globigerinoides ruber white; Magnesium/Calcium ratio; δ18O; Inductively coupled plasma atomic emission spectroscope (ICP-AES); Joides Resolution; Leg108; Ocean Drilling Program; ODP; Partial pressure of carbon dioxide; standard deviation; Partial pressure of carbon dioxide (water) at sea surface temperature (wet air); pH; Salinity; Sample code/label; Sea surface temperature; annual mean; South Atlantic Ocean; δ11B; Planktonic foraminifera
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.721741; https://doi.org/10.1594/PANGAEA.721741

The dominant period of Pleistocene glacial cycles changed during the mid-Pleistocene from 40,000 years to 100,000 years, for as yet unknown reasons. Here we present a 2.1-million-year record of sea surface partial pressure of CO2 (PCO2), based on boron isotopes in planktic foraminifer shells, which suggests that the atmospheric partial pressure of CO2 (pCO2) was relatively stable before the mid-Pleistocene climate transition. Glacial PCO2 was ~31 microatmospheres higher before the transition (more than 1 million years ago), but interglacial PCO2 was similar to that of late Pleistocene interglacial cycles (<450,000 years ago). These estimates are consistent with a close linkage between atmospheric CO2 concentration and global climate, but the lack of a gradual decrease in interglacial PCO2 does not support the suggestion that a long-term drawdown of atmospheric CO2 was the main cause of the climate transition.