摘要
江西玉山大山脚晚奥陶世三衢山期层孔虫一珊瑚礁为三山地区孤立碳酸盐岩台地内发育形成的一个点礁,是一个在纵向上由上、下两个点礁体组成的复合型和多旋回叠置礁。礁体主要由原地堆积的床板珊瑚、层孔虫和藻类构筑而成。根据礁群落的古生态研究,可划分出造架、障积、粘结、居礁、喜礁等五个群团和六个生物群落。礁组合的岩石类型以粘结-障积岩类为主,其次为粘结-骨架岩、骨架-障积岩和障积-粘结岩。礁相沉积和其发育特征,可划分出礁基底、礁核、礁间(滩)、礁前塌积和礁盖层等五个亚相。其中礁核相还可分出三个生长阶段。同时,结合区域构造背景,探讨了礁的形成、发展演化及其控制因素。
Stromatoporoids-coral reef of Sanqushan Age (Late Ordovician) at Dashanjiao, Yushan, Jiangxi is a patch reef developed and formed from an isolated carbonate platform of Sanshan area, wich is a complex and multiple-cycle superimposed reef vertically composed by upper and lower two patch reefs. The reef is mainly built up by autochthonous. accumulation, Stromatoporoids and Algae, Eofletcheriella and so on. For tabulata, it has agetolites, heliolites, plasmoporella, fletcheriella, eofletcheriella and so on. Based on paleoecology of the reef communities, it could be divided into five guilds of the constructor, baf- fler, binder, dweller and six communities. The evolution and environment of communities are discussed in the paper. Through the study of the reef petrology, it is considered that the rock types of the reef complex are dominant bind-bafflestone composed by Tabulata, Stromatoporoids and Algae: baffle-bindstone and bind-framestone as the second. The reef facies may be divided into five subfacies of reef base, reef core, inter reef deposit, reef talus and reef cap. Three growth stages, Fletchriella-Heliolites bind-framestone stage, Solenopora bind-bafflestone stage and Agetolites-Stromatoporoids bind-framestone stage, may be shown from from bottom to top in the reef core facies.
