Encyclopedia of Marine Geosciences

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Mg/Ca Paleothermometry

  • Dirk Nürnberg
Living reference work entry

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DOI: https://doi.org/10.1007/978-94-007-6644-0_98-2


Mg/Ca paleothermometry. Geochemical proxy used in paleoceanography to reconstruct past temperatures of the ocean surface.

Reliable sea surface temperature (SST) estimates are crucial to the reconstruction and modeling of past climate change. Reconstructions of the thermal state of the ocean, in turn, may help to assess the significance of instrumentally observed climate variability and may validate global circulation models used to predict future climate change. Most promising in this respect is the Mg/Ca paleothermometry, which is based on the temperature dependence of the substitution of magnesium into biogenic calcite. It has long been known that tropical calcitic shells of marine organisms are generally more enriched in magnesium than subpolar shells (e.g., Savin and Douglas, 1973). But in particular for the important group of foraminifera (marine protozoa), a well-defined and species-specific calibration of the shell Mg/Ca ratio on ocean temperature was missing until...


Oxygen Isotope Calcite Dissolution Calcite Saturation Calcitic Shell Biogenic Calcite 
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© Springer Science+Business Media Dordrecht 2015

Authors and Affiliations

  1. 1.GEOMAR Helmholtz Centre for Ocean ResearchKielGermany