Fig. 5
From: Sedimentology of reefal buildups of the Xiannüdong Formation (Cambrian Series 2), SW China
a Field photo of R 1 shows that it is an extensive horizontal bed or low-relief mound with a large diameter. The man as scale is 1.8 m high; b The polished slab (Sample 14 in Fig. 2) of R 1 shows the frame was built by irregularly-shaped aggregations of Epiphyton thalli (darker-color parts). The frame was filled with silty/sandy micrite (lighter-color parts) but had geopetal structure (red arrow) locally; c–d Photomicrographs (PPL) of R 2 framework built by Epiphyton (Ep) thalli (Sample 14 in Fig. 2). (d) is the tracing of (c). Microspar cements (s) encrusted aggregates of Epiphyton (Ep) thalli. Microspar contains few silicate grains. The space between Epiphyton aggregations is filled with silty/sandy micrite (M); e Photomicrograph (PPL) of Epiphyton (Ep) thalli in longitude section (Sample 14 in Fig. 2). The morphology is shown as fan-shaped clusters of branching filaments. Spars (s) filled the space between Epiphyton (Ep) thalli; f Photomicrograph (PPL) shows Epiphyton (Ep) thalli in transverse section as aggregation of solid dots. Spars (s) filled the space between Epiphyton (Ep) thalli (Sample 14 in Fig. 2)