Abstract: The heavy mineral assemblages and detrital rutile geochemistry of Cenozoic sandstone at Kekeya profile near the western Kunlun Orogenic belt were analyzed. Two mineral sections were identified based on the contents and features of the heavy mineral assemblages: stable and unstable heavy mineral segment, which were divided by the bottom of Atushi group (N2a). These implied a rapid uplift in the western Kunlun in the Pliocene. The content of detrital rutile derived from metapelitic decreased, while that derived from metamafic increased with rising of the profile. This result suggests that basement rocks were denudated and deposited due to rapid uplift and erosion. The metamorphic stages of detrital rutile were mainly amphibolite/elogite and granulite facies, which may result from a differential uplifting of the Western Kunlun. Since Oligocene, the west part is higher than the eastern part and becomes the main provenance area.

Key words: heavy mineral, rutile, geochemistry, provenance, Western Kunlun

摘要： 对西昆仑造山带山前叶城地区柯克亚剖面新生代砂岩样品中重矿物及碎屑金红石的微量元素进行分析, 结果表明重矿物含量及其组合特征具有明显分段性, 上新世阿图什组(N2a)底部以下为较稳定重矿物阶段, 以上为不稳定重矿物阶段, 反映西昆仑在上新世经历过一期快速隆升过程。碎屑金红石微量元素特征表明, 剖面从下至上, 源岩为泥质变质岩的比例逐渐降低, 基性变质岩的比例逐渐增高, 反映西昆仑快速隆升导致基底被抬升剥蚀, 基底岩石对物源的贡献增大。金红石母岩类型主要为角闪岩/榴辉岩相和麻粒岩相变质岩, 可能由于西昆仑西部快速隆升, 形成西高东低的地貌格局, 西昆仑西部成为该区的优势物源区。

关键词: 重矿物, 金红石, 地球化学, 物源, 西昆仑