Figure F17. Photograph showing calcareous layers in minor lithology, including an upper gradational boundary of a pure calcareous layer that consists of 95% inorganic calcite based on smear-slide observation. XRD of collected samples in this interval shows that the main constituent carbonate is calcite. Several faults and joints are visible, some filled with white calcite crystals (interval 186-1151A-101R-2, 25-46 cm).