Figure F21. XRD diffractogram and digital image of a "proto-chert" nodule from ~292.7 mcd (Sample 208-1265A-27H-6, 12 cm; 254.62 mbsf). The presence of opal-CT suggests the onset of silica diagenesis within the sequence.

Figure F21. XRD diffractogram and digital image of a "proto-chert" nodule from ~292.7 mcd (Sample 208-1265A-27H-6, 12 cm; 254.62 mbsf). The presence of opal-CT suggests the onset of silica diagenesis within the sequence.