库车盆地西北缘下第三系碳、氧同位素特征及成岩环境  

Relationships between carbon and oxygen isotopic compositions and diagenetic environments of Lower Tertiary carbonate on the northwestern margin of Kuqa Basin, Xinjiang

作　　者：傅启龙[1] 

机构地区：[1]中国科学院南京地质古生物研究所

出　　处：《地层学杂志》1996年第4期280-284,共5页Journal of Stratigraphy

基　　金：中科院院长基金

摘　　要：库车盆地西北缘及柯坪地区下第三系碳酸盐岩稳定同位素分析结果显示氧同位素组成在相对较小的范围内变化，而碳同位素组成变化很大。沉积学研究表明塔拉克组和小库孜拜组海相地层主要为潮坪、萨布哈和渴湖相沉积，在成岩过程中或成岩期后，沉积物不同程度地受到了淡水作用的影响。所分析的样品大部分形成于大气淡水成岩环境，富集１２Ｃ，δ１３Ｃ为正值的样品一般形成于海水成岩环境。稳定同位素分析是研究成岩作用的有效手段之一。Analyses of carbonate samples from the Early Tertiary marine strata on the northwestern margin of the Kuqa Basin, show a wide variability in carbon compositions and a relatively narrow variability in oxygen compositions. Sedimentological studies suggest that the Xiaokuzhibai and Talake Formations are mainly tidal flat of sabkha and lagoon facies. During the diagenesis, parts of carbonates were altered by freshwater. Samples containing petrologic evidence of meteoric diagenetic environment are marked by 12C-richment. Positive δ13C values of samples reflect their marine diagenesis. Carbon and oxygen isotope may be useful for identifying diagenetic environments of carbonate rocks.

关 键 词：库车盆地 碳同位素 氧同位素 成岩环境 下第三纪 

分 类 号：P597[天文地球—地球化学] P581[天文地球—地质学]