Figure 5
Analyses of the cross section of the bottom part of the shells of a bivalve. (a) Photograph of the cross-section imaged in visible light. (b) BSE image of the cross-section of the shells. Aragonite is white, quartz and clays are grey, epoxy is black. The arrow indicates the organic film (see also Fig. S3), which contains debris or hard minerals such as quartz and feldspars. (c) Integral map of organic and mineral distribution at the shell-siltstone interface. The aragonite that makes up the shell is blue, silicate materials are green and the organic film is red. (d) SEM image of the shell of a bivalve. No specific morphological microtexture that could have provided the bivalve with an efficient excavation ability can be seen.
