Mineralogical variability along the drill cores BDR-D1 and BDR-D2. Left: ternary diagram of the main mineral groups normalized to 100 per cent total. Core BDR-D1 is displayed as circles and BDR-D2 as crossed circles. Light grey symbols denote samples from the area of interest and in dark grey symbols denote the rest of the samples. Highlighted by green and blue polygons is the approximate mineral composition of SF2 and SF3, respectively. Right: lateral comparison of the mineralogy of the cores BDR-D1 (top) and BDR-D2 (bottom) at similar depths.