ORDOVICIAN ORGANIC REEFS IN THE LUNNAN AREA IN NORTHERN TARIM

Ordovician organic reefs were first discovered in the Lunnan area,northern Tarim.The reef types comprise the Calathium baffling buildup Palaeoporella baffling buildup Algal binding lime mud buildup Algal binding calcisiltic buildup Calcisponge-Cyanophyte baffling binding buildup.Four reef building communities are distinguished.The development of reefs was obviously constrained by the eco environment.