Fig. 6

Microfabric of the microbial carbonate of the Cambrian Stage 3 at Sugaitblak section, Aksu, Tarim, Xinjiang, NW China: presence of mold holes and crusts. a An outcrop with microbial mounds, which are mound-like, massive, composed of dolostone, and are surrounded by thin-bedded dolostone; b Enlargement of the black box in a; c Thin section of a specimen from the outcrop in b, consisting of dark wormlike and netlike “clots” (red arrows) and the bright patches of dolomite crystals (yellow arrows) between the “clots”; d Enlargement of the black box in c, with “clots” (outlined by a red dotted circle) and bright patches (outlined by a yellow dotted circle); e Enlargement of the purple box in d, which is part of a dolomite crystal (Do) with a few filamentous mold holes (red arrows) of 1–1.5 μm in diameter; f Enlargement of the red box in d, consisting of smaller dolomite crystals, more filamentous mold holes (red arrows) and rich inter-crystalline black pores (yellow arrows)