摘要:松辽盆地钱家店地区姚家组砂岩矿物、地球化学成分与源区岩石性质和沉积构造环境密切相关。岩相学观察和矿物化学分析表明，所研究的岩石主要碎屑矿物由石英、岩屑和长石组成，含少量的黄铁矿、炭屑和重矿物等矿物。地球化学特征上，这些岩石普遍具有高SiO2含量（68.4%～79.61%）、相对高的K2O/Na2O比值（1.83～2.03）和较低的Fe2O3T+MgO含量（1.48%～4.22%），稀土元素标准化配分曲线呈现轻稀土富集，重稀土平坦和弱Eu、Ce负异常特征。较低的CIA （57～63）和PIA （60～71）指数、A-CN-K以及AK-C-N分布模式还说明源区经历了相对较弱的风化作用。Zr/Sc和Th/Sc比值共同表明姚家组的碎屑组成不具备沉积再旋回的特征，说明其为近源沉积，具有较差的分选性。砂岩物源区组成判别图研究表明，姚家组砂岩的物源区主要出露长英质岩浆岩。砂岩形成构造环境判别图解及特征指数分析表明，姚家组主要形成于被动大陆边缘沉积环境。
关键词: 姚家组/
地球化学/
物源区/
构造环境/
松辽盆地
Abstract:The mineralogical and geochemical compositions of the Yaojia Formation sandstones in Qianjiadian area, Songliao Basin are intimately related to their provenance and depositional tectonic setting. Petrographical observation assorting with mineral chemical analysis indicates that the studied rocks have a major clastic mineral association of quartz+cuttings+feldspar with minor pyrite+charcoal shavings+heavy minerals and other transparent minerals. These rocks are also characterized generally by high content of SiO2 （68.4%～79.61%）, relatively high ratio of K2O/Na2O （1.83～2.03） and low concentration of Fe2O3T+MgO （1.48%～4.22%）. The REE patterns are characterized by LREE enrichment, flat HREE, and poor negative Eu and Ce anomalies. The pre-metasomatized CIA （57～63） and PIA （60～71） values, respectively, in connection with the A-CN-K and the AK-C-N modeling commonly suggest that these sediments were derived from source rocks with low-moderate weathering. And Zr/Sc and Th/Sc ratios illustrate that all sediments have undergone moderate degree of weathering and no significant sediment recycling, which indicates proximal provenances and poor sorting. Various diagrams for sedimentary provenance using major and trace elements show all the sediments studied were derived predominantly from felsic magmatic rocks source. Geochemical data for these rocks suggest a passive continental margin tectonic setting.
Key words:Yaojia Formation/
Provenance analysis/
Tectonic setting/
Songliao Basin/
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