News27.05.2014Publication of the paper "Analyses of fluid inclusions in Neoproterozoic marine halite provide oldest measurement of seawater chemistry" |
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Dr. Javier García Veigas, responsible of Scanning Electron Microscopy Technology of the CCiTUB, has published the article “Analyses of fluid inclusions in Neoproterozoic marine halite provide oldest measurement of seawater chemistry” at the review Geology. The study was conducted with the Cryo-SEM-EDS technique. The CCiTUB are a world leader in the use of this technique for the study of the composition of seawater in the geological past from the analysis of fluid inclusions in salt formations. The abstract of the article: “We analyzed primary fluid inclusions in halite from marine evaporites in the ca. 830 Ma Browne Formation of the Officer Basin in Western Australia using the cryogenic scanning electron microscopy–energy dispersive X-ray spectrometry analysis technique. The concentrations of the major ions, except K+ and possibly SO42−, fall within the range of Phanerozoic seawater. This is the first direct measurement of the composition of mid-Neoproterozoic seawater, and extends present-day knowledge of seawater chemistry by ∼300 m.y. Our estimates suggest that mid-Neoproterozoic marine sulfate concentrations were lower (∼90%) than modern values. By the terminal Neoproterozoic, fluid inclusions in halite and evaporite mineralogy indicate seawater sulfate levels rose significantly, to 50%–80% of modern concentrations, which parallels increases in atmospheric and oceanic oxygen.” | |