(Table 1) Boron, carbon, magnesium and calcium isotope data, post-Marinoan Neoproterozoic carbonate sections, Namibia

• Main Authors: Kasemann, Simone A, Pogge von Strandmann, Philip A E, Prave, Anthony R, Fallick, Anthony E, Elliott, Tim, Hoffmann, Karl-Heinz
• Format: Dataset
• Language: English
• Published: PANGAEA 2014
• Subjects: Center for Marine Environmental Sciences; Event label; Finnigan TRITON thermal ionization mass spectrometer (TIMS); Fransfontein; Khowarib; Lithologic unit/sequence; Lithology/composition/facies; MARUM; NW Namibia; Ombaatjie; PROFILE; Profile sampling; Sample code/label; SECTION; height; Uncertainty; δ11B; δ13C; carbonate; δ18O; δ26Mg; δ44/40 Ca; Triton; Ocean acidification
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.833928; https://doi.org/10.1594/PANGAEA.833928

A marked ocean acidification event and elevated atmospheric carbon dioxide concentrations following the extreme environmental conditions of the younger Cryogenian glaciation have been inferred from boron isotope measurements. Calcium and magnesium isotope analyses offer additional insights into the processes occurring during this time. Data from Neoproterozoic sections in Namibia indicate that following the end of glaciation the continental weathering flux transitioned from being of mixed carbonate and silicate character to a silicate-dominated one. Combined with the effects of primary dolomite formation in the cap dolostones, this caused the ocean to depart from a state of acidification and return to higher pH after climatic amelioration. Differences in the magnitude of stratigraphic isotopic changes across the continental margin of the southern Congo craton shelf point to local influences modifying and amplifying the global signal, which need to be considered in order to avoid overestimation of the worldwide chemical weathering flux.