Figure 7. SEM-EDS data derived from the black fossil feather region.

The six dominant elements (~95% of detected electrons) are presented in order of decreasing abundance by weight percent. Elemental map and quantitative data (Table 1) suggest the fossil feather is composed primarily of C although Fe is also abundant. In contrast, Al is localized to the sediments and not in the feather. The surrounding sediment is composed primarily of O and Si which is consistent with previous analyses³². The data demonstrate that the ~8 μm-sized spheres shown in Fig. S4 are composed of O and Si, consistent with sediment grains and not part of the original feather structure.