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Kasemann, Simone A; Pogge von Strandmann, Philip A E; Prave, Anthony R; Fallick, Anthony E; Elliott, Tim; Hoffmann, Karl-Heinz (2014): (Table 1) Boron, carbon, magnesium and calcium isotope data, post-Marinoan Neoproterozoic carbonate sections, Namibia. PANGAEA, https://doi.org/10.1594/PANGAEA.833928, Supplement to: Kasemann, SA et al. (2014): Continental weathering following a Cryogenian glaciation: Evidence from calcium and magnesium isotopes. Earth and Planetary Science Letters, 396, 66-77, https://doi.org/10.1016/j.epsl.2014.03.048

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Abstract:
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.
Related to:
Kasemann, Simone A; Hawkesworth, Chris J; Prave, Anthony R; Fallick, Anthony E; Pearson, Paul N (2005): Boron and calcium isotope composition in Neoproterozoic carbonate rocks from Namibia: evidence for extreme environmental change. Earth and Planetary Science Letters, 231(1-2), 73-86, https://doi.org/10.1016/j.epsl.2004.12.006
Kasemann, Simone A; Prave, Anthony R; Fallick, Anthony E; Hawkesworth, Chris J; Hoffmann, Karl-Heinz (2010): Neoproterozoic ice ages, boron isotopes, and ocean acidification: Implications for a snowball Earth. Geology, 38(9), 775-778, https://doi.org/10.1130/G30851.1
Coverage:
Median Latitude: -19.586229 * Median Longitude: 14.336760 * South-bound Latitude: -20.199167 * West-bound Longitude: 13.995608 * North-bound Latitude: -19.256564 * East-bound Longitude: 15.016164
Minimum SECTION, height: 0.0 m * Maximum SECTION, height: 300.3 m
Event(s):
Fransfontein * Latitude: -20.199167 * Longitude: 15.016164 * Location: NW Namibia * Method/Device: Profile sampling (PROFILE)
Khowarib * Latitude: -19.302956 * Longitude: 13.995608 * Location: NW Namibia * Method/Device: Profile sampling (PROFILE)
Ombaatjie * Latitude: -19.256564 * Longitude: 13.998508 * Location: NW Namibia * Method/Device: Profile sampling (PROFILE)
Comment:
SECTION, height [m]: heights are meters above base of cap carbonate.
#: uncertainty for Ca isotope data is ± 0.2 per mil 2 Sigma; uncertainties for Mg isotope data are valid for the last digits (2 Sigma).
+: C, O and B isotope data taken from Kasemann et al., (2005, 2010).
Ombaatjie: Ca isotope data taken from Kasemann et al., (2005).
Parameter(s):
#NameShort NameUnitPrincipal InvestigatorMethod/DeviceComment
1Event labelEvent
2Lithologic unit/sequenceUnitKasemann, Simone A
3Lithology/composition/faciesLithologyKasemann, Simone A
4Sample code/labelSample labelKasemann, Simone A
5SECTION, heightSectionmGeocode
6δ13C, carbonateδ13C carb‰ PDBKasemann, Simone A+
7δ18O, carbonateδ18O carb‰ PDBKasemann, Simone A
8δ11Bδ11B‰ SRMKasemann, Simone A+
9δ44/40 Caδ44/40 Ca‰ SRM 915aKasemann, Simone AFinnigan TRITON thermal ionization mass spectrometer (TIMS)#
10δ26Mgδ26MgKasemann, Simone A#
11UncertaintyUncertainty±Kasemann, Simone A#
Size:
419 data points

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