The interval from the middle Cambrian to the Early Ordovician is a crucial transition connecting two major evolutionary events, the "Cambrian Explosion" and the "Great Ordovician Biodiversification Event", making it key to deciphering their intrinsic relationship. The Yangtze Platform in South China, with its complete and well-developed stratigraphic successions from this interval, serves as an exceptional window for exploring this significant transition. During the Miaolingian-Furongian, however, thick, massive dolostone successions were widely distributed across the platform. Due to their lithological monotony and fossil scarcity, their stratigraphic subdivision, nomenclature, and regional correlation have long posed challenges. Furthermore, a lack of detailed studies on the Early Ordovician (Tremadocian-early Floian) shallow-water deposits in the Upper Yangtze region, coupled with highly variable lithofacies, has prevented the establishment of a refined stratigraphic framework and high-resolution correlation. Collectively, these issues have hindered a comprehensive, basin-scale understanding of the relationship between these two major biotic evolutionary events in South China.
In recent years, the Lower Paleozoic research team from the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS), has conducted extensive field investigations across the Miaolingian to early Floian shallow-water areas of the Yangtze Platform. Based on detailed field reconnaissance and a systematic review of published data, the team has generated new insights into stratigraphic subdivision, correlation, and spatiotemporal distribution patterns. These results have recently been published online in the Geological Journal of China Universities.
The studies clarified the spatiotemporal distribution patterns of Miaolingian–early Floian stratigraphic successions in the study region and, adhering to modern stratigraphic nomenclature codes, systematically proposed a revised framework.
For the Miaolingian-Furongian, researchers recognized three sedimentary facies belts: a marginal mixed dolomite/clastic facies belt, a shallow-water dolomite facies belt, and a deeper-water dolomite/limestone facies belt. It is proposed that the Hsihsiangchih, the Loushankuan, and the Sanyiutung groups represent the sedimentary successions of these three facies belts, respectively. Based on lithological differences, the Sanyiutung Group was further subdivided in ascending order into the Guanshannao, Xinping, Houba, and Maotian formations. Integrating existing stratigraphic data, these formations correspond to the middle-upper Drumian, Guzhangian-Paibian, Jiangshanian, and Stage 10, respectively. For the Early Ordovician (Tremadocian-early Floian), the team clarified the spatiotemporal distribution pattern of shallow-water deposits in the Upper Yangtze region by identifying three distinct sedimentary facies zones: a coarse-grained siliciclastic facies, a mixed coarse-grained siliciclastic-dolostone facies, and a dolomite facies. The Tangchih Formation, the Wanjuanshu-Lohanpo formations (the latter equivalent to the Putaojing-Dacao formations), and the "Tungtzu"-"Hunghuayuan" formations are now applied to designate the sedimentary successions of these three zones. Furthermore, by integrating existing stratigraphic data, the researchers reassessed the age assignments of these lithostratigraphic units.
This revised stratigraphy provides a refined temporal framework for a basin-scale understanding of the coevolution of environments and biotas in South China throughout the Miaolingian to early Floian.
These studies were jointly supported by the National Key Research and Development Program of China and the State Key Laboratory of Palaeobiology and Stratigraphy.
Reference: Wang, G. X., Zhan, R. B., Wei, X., Yan, G. Z. 2026. Lithostratigraphy, age and distribution of Miaolingian-Furongian (Cambrian) rocks on the Yangtze Platform, South China. Geological Journal of China Universities, https://doi.org/10.16108/j.issn1006-7493.2026057.
Wang, G. X., Zhan, R. B., Wei, X., Yan, G. Z., Cui, Y, N. 2026. Tremadocian-early Floian (Early Ordovician) shallow-water deposits on the Yangtze Platform of South China: Lithostratigraphy, age and distribution. Geological Journal of China Universities, https://doi.org/10.16108/j.issn1006-7493.2026094.
Fig.1 Spatial pattern of the Miaolingian-Furongian (Cambrian) strata on the Yangtze Platform, South China
Fig.2 Revised stratigraphic framework of the Miaolingian-Furongian (Cambrian) strata on the Yangtze Platform, and their correlation with strata of the Jiangnan Slope
Fig.3 Spatial pattern of the Tremadocian-early Floian (Early Ordovician) shallow-water deposits on the Upper Yangtze Platform, South China
Fig.4 Revised stratigraphic framework of the Tremadocian- early Floian (Early Ordovician) strata of near-shore facies on the Upper Yangtze Platform, and their correlation with coeval strata of the interior Yangtze region
Download：