The Huicheng basin is a well-preserved basin in the West Qinling orogenic belt. The Tianjiaba Formation, Zhoujiawan Formation and Jishan Formation in the Early Cretaceous Huicheng basin are glutenite sedimentary successions. Paleocurrent and conglomerate composition indicate sediments are proximal developed from southern and northern margin. Heavy mineral analysis result suggests source rock of Early Cretaceous sandstones are predominant magmatic rocks, minor metamorphic rocks and sedimentary rocks. Chemical classification of Early Cretaceous sandtones indicates that the analysed sediments are unstable wackes and arkose/litharenite. The REE patterns are characterized by LREE enrichment, flat HREE, and poor negative Eu -anomalies. Various diagrams for sedimentary provenance using major and trace elements show all the sediments studied were derived predominantly from felsic volcanic rocks source. Geochemical data for these rocks suggest a continental island arc setting and continental active margin. Together with regional geological evidence, the sediments were deposited in a pull-apart basin.%徽成盆地是西秦岭造山带内一个具有代表性的盆地,保留较完整的地层记录.早白垩世田家坝组、周家湾组和鸡山组为一套砂砾岩沉积组合序列.本文通过对早白垩世砂岩的古水流恢复、砾石成分与含量、重矿物和地球化学分析,对沉积岩物源区特征和原型盆地进行探讨.古水流恢复和砾石成分统计表明,沉积物主要是近源堆积,主要来自于盆地南缘和北部.重矿物研究结果表明,早白垩世砂岩母岩以岩浆岩为主,并有少量变质岩/沉积岩.地球化学分析表明,早白垩世砂岩为成熟度较低的硬砂岩和长石/岩屑砂屑岩.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负异常特征.砂岩物源区组成判别图研究表明,早白垩世砂岩的物源区主要出露长英质火山岩.砂岩源区构造环境判别图解及特征指数分析表明,早白垩世砂岩源区主要形成于大陆岛弧和活动大陆边缘.结合区域资料和前人研究,表明早白垩世徽成地区发育走滑拉分盆地.
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