松辽盆地白垩系泉头组碎屑沉积岩岩石地球化学特征及其地质意义

松辽盆地庆安地区白垩系泉头组碎屑沉积岩主要由砂岩、泥岩和粉砂岩类组成。通过对白垩系泉头组碎屑沉积岩岩石样品的岩石化学分析表明 :主元素化学分类结果主要为长石砂岩、页岩 ,少量岩屑砂岩和硬砂岩 ;稀土元素分布模式显示其明显富集轻稀土及Eu负异常 ,并与NASC和PAAS稀土分布模式相似 ;碎屑沉积岩与上地壳的微量元素含量比值曲线显示为平坦型 ,这说明沉积岩是在活动性较弱的构造背景下缓慢沉积 ,具有被动大陆边缘和活动大陆边缘沉积物的特点。松辽盆地庆安地区白垩系泉头组碎屑沉积岩物质来源于张广才岭海西期花岗岩 ,后者的物源来自于上地壳。

Petrological-geochemical characteristics of coarse-grained clastic sedimentary rocks of Quantou Formation, Cretaceous in Songliao basin and their geological significance

Clastic sedimentary rocks of Quantou Formation,Cretaceous in Qing-an area,Songliao basin are mainly composed of sandstone,mudstone and siltstone.The petrological-chemical analysis of clastic sedimentary rocks from Quantou Formation,Cretaceous indicates that their lithology mainly consists of arkose,shale and minor rock debris sandstone and greywacke by chemical classification of bulk elements.REE distribution pattern displays the apparent enrichment of LREE and negative anomaly of Eu and is similar to that of NASC and PAAS.The ratio of trace-element in sedimentary rocks to that of upper crust shows gentle character.All the above features indicate that these sedimentary rocks were slowly deposited under weakly active tectonic setting.They are sediments typical for passive continental margin and active continental margin.It is suggested that material source of clastic sediments of Quantou Formation,Cretaceous in Qing-an area,Songliao basin was originated from Hercynian granite of Zhangguangchai Mountain,and the granite was originated from upper crust.