Figure 3. High-magnification, detailed BSEI photographs. A. Bright, mixed-sediment lamina with a few dark, horizontal lines containing Ethmodiscus fragments. B. Dark Ethmodiscus lamina containing a large proportion of mixed sediment. C. Dark Ethmodiscus lamina containing little mixed sediment and many frustule fragments stacked together. D. Close-up of Ethmodiscus lamina showing the submicron- to micron-scale thickness of the Ethmodiscus fragments. E. Dark Ethmodiscus lamina containing very bright, pyritized frustule fragments. F. Cyclical alternation of dark Ethmodiscus laminae and brighter mixed-sediment laminae in the absence of horizontal burrows. All scale bars are given in the data zone at the top of the photographs.

Figure 3. High-magnification, detailed BSEI photographs. A. Bright, mixed-sediment lamina with a few dark, horizontal lines containing Ethmodiscus fragments. B. Dark Ethmodiscus lamina containing a large proportion of mixed sediment. C. Dark Ethmodiscus lamina containing little mixed sediment and many frustule fragments stacked together. D. Close-up of Ethmodiscus lamina showing the submicron- to micron-scale thickness of the Ethmodiscus fragments. E. Dark Ethmodiscus lamina containing very bright, pyritized frustule fragments. F. Cyclical alternation of dark Ethmodiscus laminae and brighter mixed-sediment laminae in the absence of horizontal burrows. All scale bars are given in the data zone at the top of the photographs.