摘要：

柴达木盆地西部地区古近系和新近系湖相碳酸盐岩主要分布于下干柴沟组上段到油砂山组，其中，下干柴沟组上段和上干柴沟组的碳酸盐岩更发育。碳酸盐岩主要岩石类型有泥晶灰岩、藻灰岩和颗粒灰岩等三大类，此外，还普遍发育由石灰质、白云质和陆源碎屑等3种组分构成的混积岩。碳酸盐岩沉积相可划分为滨湖灰泥坪、滨湖藻坪、浅湖颗粒滩、浅湖藻丘以及半深湖泥灰岩相。滨湖灰泥坪的主要岩石类型有泥晶灰岩、含陆屑泥晶灰岩、陆屑泥晶灰岩以及陆屑泥灰岩等；滨湖藻坪为藻泥晶灰岩、藻纹层灰岩、含陆屑藻泥晶灰岩；浅湖颗粒滩有亮晶或泥微晶的鲕粒灰岩、生屑灰岩和内碎屑灰岩，其次为含陆屑颗粒灰岩；浅湖藻丘为藻叠层灰岩、藻团块灰岩、藻泥晶灰岩和含陆屑藻泥晶灰岩；而半深湖泥灰岩相的主要岩石类型为泥晶灰岩、泥灰岩以及含少量陆屑泥和粉砂的泥晶灰岩或泥灰岩。碳酸盐岩沉积相表现出很强的由西南向东北的迁移性。

Abstract:

Lacustrine carbonate rocks of the Paleogeneand Neogene in western Qaidam Basin are mainly distributed from the upper member of the Xiaganchaigou Formation to Youshashan Formation,and more developed in the  upper member of the Xiaganchaigou Formation and Shangganchaigou Formation There are three types of carbonate rocks,including  micrite limestones,algal limestones and grain limestones in western Qaidam BasinThe diamictites resulting from the mixing of lime,dolomite and terrigenous clastics are widely distributed Carbonate sedimentary facies include lime mud flats and algal flats in littoral lake,grain banks in shallow lake,algal mounds in shallow lake and marls in semideep lakeetc The typesof carbonate rocks of limemud flats in littoral lake mainly include micritic limestones,micrite limestones with terrigenous clastics and marls with terrestrial clasticsetc Those of algal flats in littoral lake mainly include algal micrite limestones and algal laminar limestones and algal micrite limestoneswith terrestrial clasticsThose of grain banks in shallow lake mainly include ooid limestones with spar or micrite,bioclastic limestones,intraclastic limestones and grain limestones Those of algal mounds in shallow lake mainly include algal stromatolitic limestones, algal clast limestones, algal micrite limestones and algalmicrite limestones with terrestrial clastics Those of marls facies in deep lake mainly include micrite limestones, marls, micrite limestones or marls with little mud and silt Carbonate sedimentary facies show a strong migration trend from southwest to northeast