Continental weathering following a Cryogenian glaciation: evidence from calcium and magnesium isotopes
Kasemann, S.A. and Pogge von Strandmann, Philip A.E. and Prave, A.R. and Fallick, A.E. and Elliott, T. and Hoffmann, K.-H. (2014) Continental weathering following a Cryogenian glaciation: evidence from calcium and magnesium isotopes. Earth & Planetary Science Letters 396 , pp. 66-77. ISSN 0012-821X.
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.
Metadata
| Item Type: | Article |
|---|---|
| Keyword(s) / Subject(s): | calcium isotopes, magnesium isotopes, continental weathering, cap carbonates, Neoproterozoic |
| School: | Birkbeck Faculties and Schools > Faculty of Science > School of Natural Sciences |
| Depositing User: | Administrator |
| Date Deposited: | 30 Apr 2014 12:34 |
| Last Modified: | 02 Aug 2023 17:10 |
| URI: | https://eprints.bbk.ac.uk/id/eprint/9657 |
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