SEDIMENTARY CHARACTERISTICS OF BIOGENIC LIMESTONES IN THE UPPER DEVONIAN WANGGUANGOU FORMATION IN THE WANGJIADIAN REGION,SHANGNAN,SHAANXI

Two types of biogenetic limestones are well developed in the Upper Devonian Wang-guangou Formation in the Wangjiandian region,Shangnan,Shaanxi.They are bafflestone and bindstone,which may be subdivided,according to ecological characteristics,reef-build-ing modes and occurrences,in to bedded reefs and bioherms produced in distinctive environ-ments under different hydrodynamic conditions.Commonly,they were all formed in more turbid-and deeper-water subtidal low-energy environments.