Speciation of Mg in biogenic calcium carbonates

F Farges, A Meibom, A-M Flank, P Lagarde, M Janousch, J Stolarski
2009 Journal of Physics, Conference Series  
A selection of marine biominerals, mostly aragonitic coral skeletons were probed at the Mg K-edge by XANES spectroscopy coupled to μXRF methods and compared to an extensive set of relevant model compounds (silicates, carbonates, oxides and organic). Extensive methodologies are required to better describe the speciation of Mg in those minerals. A combination of ab-initio XANES calculations for defective clusters around Mg in aragonite together with wavelets analyzes of the XANES region are
more » ... ed to robustly interpret the spectra. When using those methodologies, the speciation of Mg ranges from a magnesite-type environment in some scleractinian corals to an organic-type environment. In all environments, the Mg-domains probed appear to be less than 1 nm in size.
doi:10.1088/1742-6596/190/1/012175 fatcat:ujklcfthhnauxfac3hrcnngrf4