Figure F3. Close-up photographs. A. Cross-bedding in diatom-rich silt of Subunit IA. B. Dolomite nodule with preserved sedimentary layering surrounded by pale yellow altered sediment. Smear slide analysis and X-ray diffractometry revealed almost pure dolomitic composition for disseminated rhombs in the yellow altered parts (XRD Sample 201-1229A-1H-3, 84-85 cm). These features also seem to be concentrated in yellow semilithified diatom ooze laminae. C. Fluid escape structure filled with quartz sand in Subunit IB. White and pale yellow mineralizations are of dolomitic composition, as shown by X-ray diffractometry. D. Boundary between Subunits IB and IC. Onset of gray diatom-poor silt and clay sediments over olive-green diatom-rich silty clay. The transition is marked by several erosional surfaces, each covered by a layer of shell debris. E. Phosphatic hardground covering a gray clay layer in Subunit IC. The surface of the clay layer is affected by burrowing.

Figure F3. Close-up photographs. A. Cross-bedding in diatom-rich silt of Subunit IA. B. Dolomite nodule with preserved sedimentary layering surrounded by pale yellow altered sediment. Smear slide analysis and X-ray diffractometry revealed almost pure dolomitic composition for disseminated rhombs in the yellow altered parts (XRD Sample 201-1229A-1H-3, 84-85 cm). These features also seem to be concentrated in yellow semilithified diatom ooze laminae. C. Fluid escape structure filled with quartz sand in Subunit IB. White and pale yellow mineralizations are of dolomitic composition, as shown by X-ray diffractometry. D. Boundary between Subunits IB and IC. Onset of gray diatom-poor silt and clay sediments over olive-green diatom-rich silty clay. The transition is marked by several erosional surfaces, each covered by a layer of shell debris. E. Phosphatic hardground covering a gray clay layer in Subunit IC. The surface of the clay layer is affected by burrowing.