Preliminary report of small shelly fossils from the uppermost Houjiashan Formation (Cambrian Series 2) in Xuzhou, Jiangsu Province
Article
Figures
Metrics
Preview PDF
Reference
Related
Cited by
Materials
Abstract:
The abundant small shelly fossils (SSFs) from the Cambrian Series 2 recovered from the North China Paltform (NCP) represent an important resource for SSF taxonomy, transcontinental stratigraphic correlations, and palaeogeographic reconstructions (specifically, reconstructing the relative palaeogeographic positions of the NCP). In recent years, many new species of SSFs from the Cambrian Series 2 have been reported from the NCP; however, one stratigraphic unit that has received little attention in this region is the uppermost Houjiashan Formation, one of the oldest Cambrian formations on the NCP. This study provides an extensive investigation of the SSF assemblage from the uppermost Houjiashan Formation. A total of 12 species belonging to 12 genera are identified; all are obtained through acid etching of materials from the Zhanglou section in northern Jiangsu Province. This assemblage includes four species of hyoliths (Cupitheca decollatea, Paratriplicatella sp., Neogloborilus spinatus, and Triplicatella xinjia), three species of brachiopods (Eoobolus sp., Schizopholis sp., and Hadrotreta sp.), two species of chancelloriids (Chancelloria cf. eros and Archiasterellateraspina), two species of bradoriids (Alutella cf. datongensis and Mongolitubulusaspermachaera), a hyolithelminth species (Hyolithellus cf. micans) along with unidentifiable sponge spicules, echinoderm sclerites, etc. The SSF assemblage from the uppermost Houjiashan Formation at the Zhanglou section in northern Jiangsu Province belongs to the trilobite Redlichia chinensis Zone. Consisting of hyoliths, brachiopods, and chancelloriids, this assemblage basically resembles the SSF assemblage of the Xinji Formation, but they differ in their mollusc compositions. Further analysis suggests that the difference is highly likely influenced by the Sinsk event. These new data indicate that the uppermost Houjiashan Formation belongs to the middle of the Cambrian Stage 4 (Longwangmiao Formation; Toyonian). This new discovery adds great material to and extends the biostratigraphical range of the SSFs from the Cambrian Stage 4 on the southern margin of the NCP. Palaeogeographical distribution of SSFs in similar strata of the neighbouring regions will be further studied to better understand the impact of the Sinsk event on the NCP.
