Continental weathering following a Cryogenian glaciation: evidence from calcium and magnesium isotopes

Kasemann, S. A., Pogge von Strandmann, P. A.E., Prave, A. R., Fallick, A. E., Elliott, T. and Hoffmann, K.-H. (2014) Continental weathering following a Cryogenian glaciation: evidence from calcium and magnesium isotopes. Earth and Planetary Science Letters, 396(2014), pp. 66-77. (doi: 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.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Fallick, Professor Anthony
Authors: Kasemann, S. A., Pogge von Strandmann, P. A.E., Prave, A. R., Fallick, A. E., Elliott, T., and Hoffmann, K.-H.
College/School:College of Science and Engineering > Scottish Universities Environmental Research Centre
Journal Name:Earth and Planetary Science Letters
Publisher:Elsevier B.V.
ISSN:0012-821X
ISSN (Online):1385-013X

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