Fig. 3: STEM-BF and –HAADF micrographs of typical organic grain morphologies at the higher resolution afforded by the STEM.

a, b Organic matter within FIBW-06 (a HAADF, b BF) showing irregular and diffuse morphologies. c, d Organic matter within FIBW-07 (c: HAADF, d: BF) showing irregular, but more compact morphologies. e HAADF image of lamella FIBW-02 with a small, globular organic grain. f HAADF image of lamella FIBW-08 showing a large and irregular organic grain intermingled with phyllosilicates and other minerals.