摘要
为了分析库车坳陷古近系库姆格列木群白云岩的成因,利用薄片染色、微量元素和稳定同位素测试等方法为手段,系统分析该套白云岩地球化学特征,并讨论其成因。研究表明,该套白云岩主要分为膏质云岩和泥(粉)晶白云岩两种类型。白云岩的微量元素和同位素特征表明其形成于较高盐度、高Mg/Ca比、强还原的海陆过渡环境。古近纪早期库车坳陷西部地区间断性海侵和强烈蒸发环境使得水体盐度较高,并为准同生期白云岩的形成提供了镁离子来源。结合沉积、岩相特征认为该套白云岩有蒸发白云石化及回流渗透白云石化两种成因类型,蒸发白云石化形成的膏质云岩主要分布在低能的潮上环境,回流渗透白云石化形成的膏质泥(粉)晶白云岩或膏质砂屑白云岩分布于中低能的潮下—泻湖环境。
In order to analyze the dolomite origin of Paleogene dolomite（Kumugeliemu group）in Kuqa depression,this article take the thin slice to dye,trace element and stable isotope test as method,and system atically analyzed this set of dolomite geochemistry characteristic and their origin.The research indicated that the dolomite mainly divide into the creaming dolomite and micrite（powder crystal） dolomite.The trace element and the isotope characteristic of dolomite indicated that it forms in high-salinity,high Mg/Ca ratio,and the strong reducing water environment.The discontinuity ingression in Kuqa depression western area in early stage of Tertiary Period and the intense evaporation environment causes the water body salinity to be high,and the water has provided the magnesium ion for dolomite＇s formation in penecontemporaneous time.Combine the deposition and lithic facies characteristic of dolomite,we think the dolomite have two kinds of genetic types： the evaporation dolomitization and reflux dolomitization,creaming dolomite that stem from the evaporation dolomitization mainly distributes in supratidal flat（that is low-energy environment）,creaming micrite（powder crystal） dolomite or creaming dolarenite that stem from the reflux dolomitization distributes in subtidal-the lagoon（that is moderate-low energy environment）.
出处
《沉积学报》
CAS
CSCD
北大核心
2010年第3期518-524,共7页
Acta Sedimentologica Sinica
基金
国家油气重大专项(编号:2008ZX05004-002)资助
