Cretaceous Paleocene Foraminiferal Communities from the Western Tarim Basin and Their Environmental Significance
塔里木盆地面西部白垩纪—古新世有孔虫群落的划分及其环境意义

Foraminifera is one of the most important fossil faunas of the marine Cretaceous and Paleocene inthe Western Tarim Basin. Several factors considered in this papor for recognizing and classifying com-munities are as follows:1. Easily distinguishable composition and structure of community;2.The internal uniformity of community-the difference among the members within one com- munity is less distinct than that between the members of it and other communities;the differencesamong the distribution areas of the same community less distinct than those among the distribution ar-eas of different communities:3.Easily recognizable boundaries between communities;4.Definite continuity and rcappearance of geographical distribution;5.The role of endemic genera and species.According to fhe above criteria,the Cretaceous-paleocene foraminifera in the Western TarimBasin can be de divided into 9 communities. The communities are named after characteristic genera(Table1). This paper deals mainly with the changes of Paleoceanographical environments in which theforaminiferal communities existed,especially with the changes in temperature and salinity revealed byanalyses of test composition and trace elements in the test,and by statistic studies of species density,richness,diversity, equitability and dominance.