Figure 4
TEM characterizations of a FIB thin section excavated from the bottom of a small macroboring (location (iii) in Fig. 1). (a) SEM image of the FIB thin section, showing the poorly consolidated assemblage of minerals in the area that was contacting the bivalve. (b) TEM image of the FIB thin section, showing ground quartz and an area enriched in C and N (labeled “biofilm” on the figure). (c) EDX spectrum of the biofilm. (d) EDX color map of the biofilm area shown in (b). Mn, Si and N are represented by blue, green and red colors, respectively. Note the occurrence of nanosized quartz debris. (e) Selected area electron diffraction of the amorphous biofilm and the Mn-bearing crystals.
