Fig. 4

Data collected from the ground layer of cross section S6 from Iberia #25 (1948). Top left, Raman spectrum, displaying the distinctive bands of rutile at 143, 447, 608 cm⁻¹ and of anhydrite at 416, 498, 608, 626, 675, 1018, 1130 cm⁻¹. Broad features at ca. 1227, 1312, 1395, 1608, 1691 cm⁻¹ are attributed to the luminescence emission of Nd³⁺ of composite titanium dioxide pigments produced by co-precipitation with BaSO₄ or CaSO₄. Top right, EDS spectrum collected from an area in the left portion of S6, along with the corresponding BSE image showing the typical sheet structure of talc. Bottom, EDS elemental maps of Ti Kα, Ca Kα, S Kα, Mg Kα, and Si Kα, acquired from the central portion of S6