广西二叠纪生物礁的特征和分布规律

FEATURES OF PERMIAN REEF IN GUANGXI AND ITS DISTRIBUTING REGULATION

广西二叠纪生物礁（丘）非常发育，自栖霞期至长兴期均有分布，以茅口期最繁盛。生物礁主要发育于具陡斜坡的孤立浅水台地边缘，包括堤礁、马蹄形礁、环礁、链状礁和块状礁。逅礁生物以钙质海绵为主，另有水熄、管壳石、苔藓虫及红藻等。包覆粘结生物以古石孔藻、层纹状蓝绿藻为主，附礁生物为底栖生物和藻类。礁岩类型以复合型为主，包括包覆骨架岩、粘结骨架岩、包覆障积粘结岩、包覆粘结岩等。生物丘则主要产在碳酸盐缓坡、孤立台地缓斜坡及台凹环境，包括珊瑚丘、海绵丘、荷叶藻丘、生物屑藻灰泥丘和藻泥丘，常与陆棚相深灰色泥岩、生物屑粒泥岩、泥粒岩及风暴岩构成旋回组合。生物礁、丘的分布受古特提斯海的扩张和同沉积断裂所控制。

The Permianh（biogical reef （knoll）in Guangxi was much developed and lasted fromXixa Stage to Changxing Stage，among which Maokou Stage was the most prosperous。The reef occurs mainly in the margin of isolated shallow platform with steep slope。It is di-vided in shape into five types ：dam reef， horse-shoe reef，ring reef，chain-like reef andmassive reef． Reef-building organism is made up of by calcareous sponge，in part by hydra， Tubiphytes，polyzoa， red algae，etc。Bundling一binding organism is dominated byArchaeolithoporella， laminated cyanophyta， Reef-attaching organism consists of benthosand algae。The type of reef rock is dominated by composite rock，including bundle skele-ton rock，binding skeleton rock，bundle barrier bindstone，bundle bindstone，etc。The bi-ological knoll lies mainly in gentle carbonite slope，the slope of isolated platform and thedepression of platform， and occurs as coral knoll，sponge knoll， Lotus-phylloid algalknoll， bioclastic marl knoll and algal mud knoll，and constitutes cycle association with thedark mudstone， bioclastic mudstone， mudstone and stormstone in shell facies。The distri-bution of biological reef and knoll are controlled by the expansion and synsedimentary faultof Palaeotethvs Sea.