中文摘要：

沉积物中重矿物的分布受物源区、构造抬升与剥蚀作用、古地貌以及古气候、古环境等多种因素影响,因此可将重矿物的研究应用于物源、沉积环境的分析。通过对川东南-湘西地区下志留统小河坝组砂岩重矿物的相关分析,提出川东南与湘西地区小河坝组砂岩的物源方向不同,川东南小河坝组砂岩的物源方向为由南东到北西,即来源于雪峰山隆起的南西段;湘西小河坝组砂岩的物源方向为由东北到西南,即来自雪峰山隆起的北东段。重矿物组合表明川东南地区的物源主要由古老的沉积岩再旋回沉积物、基性-超基性侵入岩体和中基性喷出岩构成;湘西地区的物源主要为更老的沉积岩及其所夹少量中基性喷出岩,总体形成于稳定物源的构造沉积环境。砂岩中的指相重矿物黄铁矿和赤（褐）铁矿特征及其分布反映了小河坝组砂岩沉积期靠近黔中隆起和雪峰山隆起为水体较浅的氧化环境,而在川东南存在南川和秀山-沿河2个深坳区,为深水还原环境。

英文摘要：

The distribution of heavy minerals in deposits is subjected to the provenance,tectonic uplifting,palaeogeomorphology,paleoclimate and paleoenvironment,etc..So pepole can make the most of the research of heavy minerals in order to analyze the provenance and sedimentary environment.By the relative analysis of heavy minerals,this article illustrates that the provenance direction of the sandstones of the Lower Silurian Xiaoheba Formation in Southeast Sichuan is from southeast to northwest,that is to say,the provenance comes from the southwest section of the Xuefengshan uplift,and the provenance direction of the sandstone of the Lower Silurian Xiaoheba Formation in West Hunan is from northeast to southwest,that is to say,the provenance comes from northeast section of the Xuefengshan uplift.The heavy mineral assemblages indicate that the provenance mainly consists of multi-cycle sedimentary rocks,basic rocks,ultrabasic rocks,and basic-intermediate effusive rocks in Southeast Sichuan,the provenance mainly consists of order sedimentary rocks and a few intermediate effusive rocks formed in the stable tectonic-sedimentary environment.The characteristics and distribution of the pyrite and brown hematite in the Xiaoheba stage indicate that the Xuefengshan uplift and Qianzhong uplift are oxidized environment,while the Nanchuan and Xiushan-Yanhe are two depressions in a reducing environment.