Figure F25. Microfacies texture of laminated dark calcareous claystone (Subunit IIIB; Aptian-Albian; Sample 192-1183A-53R-3, 112-114 cm; plane-polarized light; field of view = 0.7 mm; photomicrograph ID# 1183AS_18). Planktonic foraminifers have been partially replaced or filled with dark opaque mineral (perhaps pyrite that was later altered to iron oxyhydroxide) and calcite.

Figure F25. Microfacies texture of laminated dark calcareous claystone (Subunit IIIB; Aptian-Albian; Sample 192-1183A-53R-3, 112-114 cm; plane-polarized light; field of view = 0.7 mm; photomicrograph ID# 1183AS_18). Planktonic foraminifers have been partially replaced or filled with dark opaque mineral (perhaps pyrite that was later altered to iron oxyhydroxide) and calcite.