FIGURE 1. Original location of all the studied sites and samples.
FIGURE 2. Sampling of the Museu de la Ciència CosmoCaixa natural collection with portable XRF. A) Sampling of Hakel (Lebanon) Cretaceous site, within a Rhinobatos sp. (MCFO-0521). B) Sampling of Hjoula (Lebanon) Cretaceous site, within fossils of Beryciformes fishes, Picnodontiformes, Armigatus sp. and Triplomystus sp. (MCFO-0372).
FIGURE 3. Compositional mapping with micro-XRF for different elements. The upper panels correspond to plant MCD-8492 (Montsechia vidalii) and the lower panels to teleostean fish MCD-7163 from the Museu de la Conca Dellà collection. The intensity of color indicates a qualitative measure of abundance for each individual element. Scale bar equals 5 mm.
FIGURE 4. Selection of X-ray fluorescence spectra of three samples studied in this work (Solnhofen, Pedrera de Meià, and Haquel). The results obtained for other samples are in general similar to those plotted in the figure. In all cases, the spectra are dominated by strong Ca alpha and Ca beta peaks around 4 keV. In addition, other features arising from minor elements in the limestone samples show up in the spectra (K, Fe, Rb, Sr, etc.). Remarkably, the XRF spectra from Solnhofen and LPM (black and red curves, respectively) are very close to each other, with only minor intensity variations among peaks. In contrast, the spectrum from Haquel (blue curve) shows increased signal for many of the detected elements (K, Fe, Sr). This observation suggests that Haquel samples tend to display larger amounts of elements like K, Fe, and Ti, which can be attributed to a detrital origin. The similarity between Solnhofen and LPM limestones might indicate similar depositional conditions in these two sites.
FIGURE 5. Plot of the intensity of the Fe and Sr peaks, as extracted from the XRF spectra (see text) for all the samples analyzed in the present work.
FIGURE 6. Plot of the intensity of the K and Ca peaks, as extracted from the XRF spectra (see text) for all the samples analyzed in the present work.
FIGURE 7. Principal Component analysis of the studied samples. Framed plot is the enlargement of the smaller values of each component.
FIGURE 8. X-ray fluorescence spectra from samples from LPM treated with different concentrations of Paraloid®-B72. Note the logarithmic scale.
