FIG. 9.

Images of sections of cyanobacterial mats mineralized with silica and aragonite demonstrating differences in preservation potential of the two mineral phases. (A) Section of filamentous mat showing alternation of silica and aragonite layers photographed in plain light. (B) Magnified section of cyanobacterial mat mineralized with silica and aragonite showing perfectly preserved silicified cyanobacteria co-occurring with poorly preserved filaments permineralized with aragonite. (C and D) Section of the same filamentous mat as in (A) irregularly mineralized with silica and aragonite photographed in plain (C) and polarized (D) light.