Figure 4
Analyses of samples with globules. (a–c) ‘Ro-2.2’ (‘Sideroxylon salicites’). (a) Overview photo of the brown leaf embedded in white mineral. (b) Compositional contrast (BSE) SEM image showing organic leaf material dark, background mineral (left part) bright, and ghost mineral inclusions in the leaf area (bright). The fractured globules (e.g., Spot 3) appear dark, indicating organic material. (c) EDX spectra show the composition of background sediment (Spot 1; mainly Si and O), the leaf area ‘Spot 2’ (Si, C, O, and traces of S and Al), and globules (Spot 3; mainly C with little O and S). (d–f) ‘Ro-110.6’ (‘Magnoliopsida’). (d,e) Overview photos showing the leaf embedded in coal. (f) Combined SEM topographic contrast and element-mapping image showing Ca in green and Si in red; organic structures are in grey scales. The EDX spectrum in the box shows the co-localization of Ca, S, and O as calcium sulphate (CaSO4). Globules are organic (C and little O). Many cavities contain a shell of CaSO4 which had surrounded the globules which have been torn out of the coal matrix. Calcium sulphate occurred also on other parts of the sample in form of gypsum deposits (e). Scale bars: (a,e) = 5 mm; (b,f) = 100 µm; (d) = 20 mm.
