Science in China Series D: Earth Sciences © 2008 SCIENCE IN CHINA PRESS Springer Sci China Ser D-Earth Sci | Nov. 2008 | vol. 51 | no. 11 | 1646-1657 www.scichina.com earth.scichina.com www.springerlink.com Anachronistic facies in the Lower Triassic of South China and their implications to the ecosystems during the recovery time ZHAO XiaoMing 1,2 , TONG JinNan 1† , YAO HuaZhou 2 , ZHANG KeXin 1 & ZQ CHEN 3 1 Key Laboratory of Biogeology and Envionmental Geology of Ministry of Education, State Key Laboratory of Geological Process and Mineral Resources, China University of Geosciences, Wuhan 430074, China; 2 Yichang Institute of Geology and Mineral Resources, Yichang 443003, China; 3 School of Earth and Geographical Sciences, the University of Western Australia, Crawley, WA6009, Australia The end-Permian mass extinction not only severely distressed the Paleozoic ecosystems but also dramatically changed the sedimentary systems, resulting in a peculiar Early Triassic ecosystem and submarine environment during the recovery time following the mass extinction. The Lower Triassic is characteristic of the wide occurrence of various distinctive sediments and related sedimentary struc- tures, such as flat-pebble conglomerates, vermicular limestone, subtidal wrinkle structures, microbial- ite, carbonate seafloor fans, thin-bedded limestone and zebra limestone-mudstone. These sediments were common in the Precambrian to Early Ordovician marine settings, and then they occurred only in some extreme and unusual environments with the expansion of metazoan faunas. However, the Early Triassic witnessed an “anachronistic” reappearance of some distinctive sedimentary records in normal shallow marine settings. The study of these anachronistic facies should be of great importance for the understanding of the unique ecosystem and marine environment through the great Paleozoic-Mesozoic transition. The anachronistic facies characterized by vermicular limestone have been documented in many localities in South China and occur at various horizons of the Lower Triassic. Most types of re- ported distinctive sediments over the world have been observed in the Lower Triassic of South China. This provides an excellent opportunity for understanding the Early Triassic environment and its co- evolution with the biotic recovery. Among the anachronistic facies the vermicular limestone is the most characteristic and common distinctive sediments in the Lower Triassic of South China but has received relatively few investigations. Taking it as a case study, we will detail the variation of vermicular lime- stone and its stratigraphic distribution in the Three Gorges area, Hubei Province. The investigation on the vermicular limestone and other distinctive sediments from the Lower Triassic of South China fur- ther indicates that the appearance of anachronistic facies immediately following the mass extinction and the elimination from normal shallow marine facies with the radiation of Mesozoic marine faunas imply the natural response of the sedimentary systems and ecosystems to the great Paleo- zoic-Mesozoic transitional events and their induced harsh environments. Therefore, the ups and downs of the anachronistic facies may act as a proxy for the evolution of ecosystems independent of fossil analyses. Early Triassic, anachronistic facies, biotic recovery, ecosystem, Three Gorges area, South China Received June 16, 2008; accepted August 28, 2008 doi: 10.1007/s11430-008-0128-y † Corresponding author (email: jntong@cug.edu.cn) Supported by NSFC Innovation Research Group Program (Grant No. 40621002), MOE Innovative Research Team Program (Grant No. IRT0546), China Geological Survey Project (Grant No. 1212010610709), and “111” Project (Grant No. B08030)