中国科学院南京地质古生物研究所机构知识库

Quarrying across a potential GSSP of the base of Cambrian Stage 5/Series 3 at the Wuliu-Zengjianyan section in south China indicates a significant change in trilobite and brachiopod faunas. The Wuliu Quarry spans approximately 4.5 m across the potential boundary, which is the FAD of Oryctocephalus indicus (Reed, 1910) in the Wuliu-Zengjiayan section of the Kaili Formation. Trilobite taxa found consist of one Pagetia, one Redlichia, one Burlingia, two Olenoides, eleven oryctocephalid, and seven ptychopariid species. Non-trilobite taxa found in the Wuliu Quarry, but not described in this publication, include tubular shells, inarticulate and articulate brachiopods, molluscs, echinoderm plates, sponges, algae, acritarchs, and trace fossils. Collected specimens display both flattening, secondary calcite preservation, and tectonic distortion. Many of the species have previously been based on length to width ratios. Given the range of morphologies demonstrated in these collections, several previously named species have been synonymized. Detailed collections from the Wuliu Quarry show that the faunas of the Ovatoryctocara cf. granulata-Bathyonotus holopygus and the O. indicus zones changed in a 20 cm, relatively barren interval. This faunal turnover does not coincide with a lithologic change and suggests that the section would be a good location for the GSSP of the base of Cambrian Stage 5/Series 3.