(Table 1) Strontium isotope ratios of planktonic foraminifera and ostracoda from ODP Hole 120-748B on the Kerguelen Plateau, Indian Ocean

• Main Authors: Zachos, James C, Opdyke, Bradley N, Quinn, Terrence Michael, Jones, Charles E, Halliday, Alex N
• Format: Dataset
• Language: English
• Published: PANGAEA 1999
• Subjects: 120-748B; DEPTH; sediment/rock; DRILL; Drilling/drill rig; DSDP/ODP/IODP sample designation; Joides Resolution; Leg120; Ocean Drilling Program; ODP; Sample code/label; Sample type; South Indian Ridge; South Indian Ocean; Strontium-87/Strontium-86 ratio; error; Antarc*; Antarctic; Antarctica; Planktonic foraminifera
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.695370; https://doi.org/10.1594/PANGAEA.695370

Stable and radiogenic isotopic and sedimentological data from sub-Antarctic deep sea sediment cores reveal a temporal link between changes in seawater 87Sr/86Sr ratios and major episodes of late Eocene-early Oligocene climate change. The 87Sr/86Sr records show two major inflections, one at 38-39 Ma near the middle/late Eocene boundary, followed by another at 33.4 Ma. Similarly, the oxygen isotope, ice-rafted debris, and clay assemblage records indicate two important climatic events: the appearance of alpine glaciers and/or small ice-sheets on Antarctica in the late Eocene at 38-39 Ma, followed by a rapid transition to larger and more permanent temperate ice-sheets in the early Oligocene at 33.4 Ma. Moreover, during the early Oligocene 30-33 Ma. three to four inferred peaks in glacial activity appear to coincide with subtle steps in the 87Sr/86Sr record. The coupled variations in climate and seawater Sr isotope ratios during the Eocene/Oligocene imply a strong causal link between the two. Either changes in climate directly influenced patterns of continental weathering and hence seawater chemistry, and/or a tectonic event e.g., uplift.as reflected in weathering and seawater chemistry triggered relatively abrupt changes in global climate.