广西南丹县六寨泥盆纪生物礁

南丹县六寨生物礁,产于中泥盆世东岗岭组中。它长4.5km、宽300m,最大厚度达158m,是广西最大的生物礁之一。该礁体属台地边缘相中的堤礁,可细分为六个亚相。岩石类型有棘屑灰岩,塌积角砾岩,生物屑灰岩,层孔虫——珊瑚灰岩、泥晶灰岩等。造礁生物有层孔虫、刺毛类,附礁生物有珊瑚、腕足类、棘皮类等。礁体生长经历了二个阶段,五个造礁时期,至东岗岭末期即告结束。

DEVONIAN BIOHERM IN LIUZHAI,NANDAN COUNTY,GUANGXI PROVINCE

The bioherm in Liuzhai,Nandan,Guangxi,occurs in the Middle Devonian Donggangling Formation on the eastern side of the Danchi fault in Guangxi.It is 4500m long and 300m wide,with a maximum thickness of 158m,and is one of the largest hioherms in Guangxi. The bioherm belongs to a barrier reef in the carbonate platform margin facies.It may be divided into the reef slope,reef core,reef base,reef crest, reef flat and reef cap.Rock types include clastic limestone,collapse breccia limestone,spheroidal stromatoporoid skeleton limestone,bioclastic sard-sized limestone,nodular stromatoporoid muddy limestone,coral limestone and micrite. Reef-building organisms are mainly spheroidal and subspheroidal stromatopoids and chaetelids,and the organisms adhering to the reef are corals,brachiopods and echinoderms.In the late Dongganglingian period the growth of the bioherm underwent two major stages and five reef-forming epochs,and by the terminal Dongganglingian time the reef-forming processes ended.