贵州中三叠世生物礁

贵州中三叠世生物礁,早在六十年代中期,殷鸿福、杨遵仪就已提出线索。作者在六十年代初研究贵州三叠纪地层时,已对三叠系相变带的特征和规模,以及板庚碳酸盐岩体有了初步认识。七十年代初,作者又到花江进行调查,发现一套壮观的藻礁灰岩。

THE MIDDLE TRIASSIC REEF IN GUIZHOU PROVINCE

This paper deals with two kinds of reef: Barrier-feef and atoll. Our research indicates that most of the organism are Solenoporacae belonging to red algae and that the growth base is composed of algal fragments and algal nodules, which are in the form of thick growth and layer upon layer superimposing on the older algal beds.The barrier reef found in linear distribution in the studied region runs in hundreds of kilometers to form a chain of reef steeply dipping seaward. Therefore, the narrow jogsaw-like edge of fore-reef facies together with the slip slope and talus give a distinct picture of zigzag reef margin, which gradually developed as an algal flat with an extensively distributed blue-algal sheet towards the back-reef. The thickness of the flat is usually doubled as compared with that of its flank. Moreover, the Anisian and Ladinian reefs occurred more or less along an identical line and exhibited a clear inherency that is probably related with the ancient basement faults.Owing to its close relation with the ancient structures, the atoll chiefly situated at the intersection of the N-S and E-W tectonic belts. The reef bodies are formed on the base of a raising carbonate buildup associated with the Upper Permian reef of Wujia-ping formation.The authors devided the reef into the following seven facies zone: (1) semiabyssal basin, (2) basin margin, (3) carbonate platform (high energy zone), (4) carbonate platform edge (reef ridge), (5) algal flat, (6) restricted marine carbonate platform, (7) eidal flat of carbonate platform.