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![[Figure 2]](il5052fig2mag.jpg)
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Figure 2
Mapping of the two speciation states of cerium in a well preserved Cretaceous teleost ?gonorynchiform fossil fish from Morocco (MHNM-KK-OT 10, ∼100 million years old). (a) Photograph of the fossil. (b) Light microscopy image of the spot denoted by a star in (a). (c) Corresponding [Ce(IV)]/[Ce(tot)] ratio (scan step: 2 µm × 2 µm, 6466 pixels). (d) Total cerium content [Ce(tot)] determined from post-edge spectral decomposition (5900 eV). (e) C sum(v,z) map. Note the similarity and improved signal-to-noise with respect to the cerium map in (d). (f) µXRF spectrum from a single spot and mean spectrum from the full map, calculated from subtraction of the spectra collected at 5726 eV from that collected before the edge at 5680 eV. The difference spectrum reveals the specific contribution of the excited fluorescence lines from cerium. (g) Kernel density estimates of the [Ce(IV)]/[Ce(tot)] distribution from areas corresponding, respectively, to fossilized muscles (black curve; 915 pixels, bandwidth: 0.009) and to bone (grey curve; 915 pixels, bandwidth: 0.006). Data collected at the Lucia beamline of the SOLEIL synchrotron. |
![[Figure 2]](il5052fig2.jpg)
 | JOURNAL OF SYNCHROTRON RADIATION |
ISSN: 1600-5775
