Fig. 4

Microfabric features of modern microbial carbonates from Shark Bay of Australia (a, b) and the Bahamas (c, d, e): presence of mold holes and crusts. Diameters are marked by red dots. a Modified from the Fig. 3b of Jahnert and Collins (2011), known as colloform structure, showing laminated microfabric comprising alternating lamellae of carbonate and voids; b Enlargement of the red box in a, showing that the mold holes (H) are circular or wormlike, with diameters of 125–250 μm, and surrounded by white carbonate crusts (C) of 125 μm thick; c Modified from Fig. 49A of Patterson (2014), hand specimen, oolitic thrombolites, with white ooids and the yellowish and brownish algal filaments between the ooids; d Enlargement of the red box in c, showing two algal filaments (T) with diameters of 23 μm and 46 μm, respectively, which are enclosed by opalescent carbonate crusts (C) of 38 μm thick; e Enlargement of the blue box in c, showing many mold holes (H) and milky-colored carbonate crusts (C) between the white ooids (O), and the diameters of the mold holes are 34–43 μm