Fig. 11

Sedimentary characteristics of the Chengkou manganese stromatolites. a Vertical view of cut slabs of columnar stromatolites, in which the micrite rhodochrosite underlies the stromatolites and the intraclastic rhodochrosite overlays; a scour surface developed, which indicated that hydrodynamic strengthening events terminated the growth of stromatolites; sample ZK02-b4; b Vertical view of cut slabs of columnar stromatolite biostrome, in which fine-grained oncolites with parallel bedding overlaid the stromatolite biostrome; a scour surface developed, which indicated a sedimentary sequence with increasing hydrodynamic force