湖南新屋场二叠纪海绵-藻礁

Permian sponge-alga reef in Xingwuchang of Hunan

湖南新屋场二叠纪海绵 -藻礁沿滨浅海台地相带和盆地相带的界线分布 ,生长在台地的边缘 它们是由海绵和藻类为主形成的障积 -骨架礁 在礁的不同部位可认别出 4个生物群落 Cyclocyclicus群落以丰富的海百合为特征 Squamularia以各种腕足类为特征 Peronidella -Amblysiphonella群落和Peronidella -Sollasia群落主要由海绵组成 礁只发育在因断裂作用而抬升的部分海底上 礁生长于一个缓慢的海侵期间 ,结束于一个大的海退 图 8,参

Permian sponge-alga reefs in Xingwuchang of Hunan are distributed along the boundary between the sublittoral flat facies zone and basin facies zone and therefore grew on a shelf edge. They are baffle-frame reefs, built mainly by sponges and algae. Four communities are recognized in the different parts of the reefs. The Cyclocyclicus community was characterized by the abundance of crinoids. The Squamularia community was characterized by various brachiopods. The Peronidella-Amblysiphonella community and Peronidella-Sollasia community were composed mainly of sponges. The reefs only developed on parts of the seafloor elevated by faulting. Reef growth occurred during a gentle transgression and was ended by a large regression.8figs.,5refs.