Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
6438023 | Geochimica et Cosmochimica Acta | 2015 | 21 Pages |
Abstract
Using the validated fossil coral archive we reconstruct seawater Mg/Ca and Sr/Ca ratios, measured by Secondary Ion Mass Spectrometry (SIMS), back to â¼230 Ma. The effects of temperature on coral trace element incorporation cannot explain the trends observed in our fossil coral Mg/Ca and Sr/Ca data. In agreement with independent records, seawater Mg/Ca molar ratios inferred from corals are low (Mg/Ca â¼1) during the Cretaceous and Jurassic, and increase between the Early Cenozoic and present (Mg/Ca = 5.2). Seawater Sr/Ca ratios from corals vary systematically between â¼8 and 13 mmol/mol since 230 Ma, with maximum values in the Cretaceous and Paleogene. The coral Sr/Ca record disagrees with records from hydrothermal CaCO3 veins, but is similar to those reconstructed from other biogenic carbonates, especially benthic foraminifera. The agreement between corals and other archives, for both Sr/Ca and Mg/Ca ratios, further validates our records. In return, fossil coral records improve our understanding of past variations in seawater Mg/Ca and Sr/Ca.
Related Topics
Physical Sciences and Engineering
Earth and Planetary Sciences
Geochemistry and Petrology
Authors
Anne M. Gothmann, JarosÅaw Stolarski, Jess F. Adkins, Blair Schoene, Kate J. Dennis, Daniel P. Schrag, Maciej Mazur, Michael L. Bender,