中文摘要：

本文对中国南海西沙群岛琛科2井中新世以来的珊瑚藻组成进行了初步研究，共识别出3科4亚科11属，包括石叶藻亚科石叶藻属（Lithophyllum）和蟹手藻属（Amphiroa）；宽珊藻亚科似绵藻属（Spongites）、新角石藻属（Neogoniomhon）和石孔藻属（Lithoporella）；珊瑚藻亚科让氏藻属（Jania）和珊瑚藻属（Corallina），无节珊瑚藻亚科中叶藻属（Mesophyllum）、奇石藻属（Aethesolithon）和石枝藻属（Lithothamnion）；孢石藻亚科孢石藻属（Sporolithon）。并得出以下认识：（1）珊瑚藻类群，指示浅水环境；无节珊瑚藻类群，指示深水环境；宽珊藻类群，指示最浅水环境；石叶藻类群，指示浅水环境。（2）琛科2井自下而上分为7个组合：让氏藻属-珊瑚藻属-石孔藻属组合；奇石藻属组合；中叶藻属-石枝藻属组合；似绵藻属组合；石枝藻属组合；中叶藻属-石叶藻属组合；石孔藻属-石叶藻属组合。（3）878．21m的珊瑚礁碳酸盐岩心，以309．00—312．00m为界，分为两个大沉积旋回。第一个沉积旋回珊瑚藻组合经历了具关节的珊瑚藻属-让氏藻属-石孔藻属组合，奇石藻属组合，石枝藻属-中叶藻属组合，似绵藻属组合的变化，反映了水体由浅加深，到最后又变浅的过程；第二个沉积旋回珊瑚藻组合出现了似绵藻藻属组合，石枝藻组合，中叶藻属-石叶藻属-石孔藻属组合，石叶藻属组合的变化，反映了水体由浅加深再变浅的珊瑚藻组合的相应变化。

英文摘要：

The coralline algae recognized in well Chenke-2, Xisha Islands since the Miocene include 11 genus in 3 families, 4 subfamilies. They are Lithophylloideae Lithophyllum Amphiroa; Mastophoroideae Spongites, Neogoniolithon and Lithoporella ; Corallinoideae Jania and Corallina, Melobesiodideae Mesoph yllum, Aethesolithon and Lithothamnion ~ and Sporolithaceae Sporolithon. The algae categories were considered to be linked to different water depth. Corallinoid indicates a shallow water environment; Melobesioid indicates a deep water environment; Mastophoroid indicates a most shallow water environment; and Lithophylloid indicates a shallow water environment. There are 7 coralline algae assemblages identified from bottom to top. They are Jania-Corallina Lithopoerlla assemblage, Aethesolithon assemblage, Mesophyllurn：Lithoth- amnium assemblage, S[ongites assemblage, Lithotharnnium assemblage, Mesojhyllurn-Lithotharnniurn assemblage and Lithopoerlla-Lithophyllum assemblage. The 878. 2Ira-thick coral reef carbonate sequence can be divided into two large sedi mentary cycles with aboundary at 309--312. In the lower sedimentary cycle, coralline algae bottom-up experienced Jania- Corallina-Lithopoerlla assemblage, Aethesolithon assemblage, MesophyZlurn：Lithothamniurn assemblage and S[ongites as- semblage （Corallinoid-Melobesiodid-Mastophoroid）, reflecting the process of water depth of shallow-deep-shallow. In the upper sedimentary cycle, Lithothamnium assemblage, MesophyllurnLithotharnniurn assemblage, Lithopoerlla-LithoDhyl- lurn assemblage （Melobesiodid-Lithophylloid） were occured from bottom to top, reflects another the process of water depth of shallow-deep-shallow.