鸡西盆地白垩纪碎屑岩地球化学特征及其对物源的制约  

Geochemical characteristics of Cretaceous detrital rocks and their constraint on provenance in Jixi Basin

作　　者：王杰[1] 和钟铧[1] 刘招君[1] 杜江峰[1] 王伟涛[1] 

机构地区：[1]吉林大学地球科学学院,吉林长春130026

出　　处：《世界地质》2006年第4期341-348,共8页World Geology

基　　金：国家油气专项项目(XQ200407)

摘　　要：鸡西盆地白垩系包括下白垩统滴道组、城子河组、穆棱组、东山组、猴石沟组及上白垩统海浪组等。白垩纪碎屑岩主量元素地球化学特征具有高SiO2、低Fe2O3、FeO、MgO的特点,说明白垩纪碎屑岩的源岩主要为长英质岩石。岩石的稀土元素具轻稀土元素富集,重稀土相对亏损,具弱的负Eu异常,其特征类似于上地壳特征。白垩纪碎屑岩微量元素的含量与上地壳微量元素的含量基本一致。综合分析砂岩的常量元素、微量元素和稀土元素的地球化学特征和构造判别图解,可以认为,城子河组砂岩主要反映被动大陆边缘的源区构造背景,穆棱组砂岩反映活动大陆边缘源区背景,猴石沟组砂岩反映的源区为大陆岛弧源区构造背景。结合古水流方向和岩屑所反映的源区岩性特点,认为小兴安岭—张广才岭造山带构造杂岩是鸡西盆地白垩纪沉积碎屑岩的主要物源。但随着物源区剥蚀深度的增加,基底古老变质岩也占有相当的比重。The Cretaceous Strata in Jixi Basin comprises Didao-, Chengzihe-, Muleng-, Dongshan and Houshigou formations （Lower Cretaceous）, and the Hailang Formation （Upper Cretaceous）. The geochemistry of major elements of Cretaceous detrital rocks shows high content in SlOe and low content in Fe2O3, FeO, MgO, which proves that the source rocks of Cretaceous detrital rocks are mainly composed of felsic. The ∑ REE patterns display ∑LREE-rich but ∑HREE-depletion, with Eu weak negative anomaly, which show the types of the upper crust. Their trace element compositions are identical to those of the upper crust. The comprehensive study on the major elements, REE, trace elements and discriminant diagrams of the geochemical composition for the tectonic setting reveal that the provenance of the detrital rocks in the Chengzihe Formation attributes to the passive continental margin, and in the Muleng Formation show that the provenance belong to the active continental margin, while the detrital rocks in Houshigou Formation show the provenance may be at continental island arc. Connected with the paleocurrent and the characters of the debris, the tectonic complex in Xiaoxing＇ anling-Zhangguancailing orogen is regarded as the main provenance of the Cretaceous detrital rocks in the Jixi Basin. However, varying with the denuding depths in source area, the metamorphic rocks from the base are richer.

关 键 词：地球化学 白垩纪碎屑岩 物源 鸡西盆地 

分 类 号：P534.53[天文地球—古生物学与地层学] P588.21[天文地球—地质学]