中文摘要：

华南地块在冈瓦纳大陆中的位置长期以来存在较大的争议，为了探讨华南地块早古生代期间的古地理位置，本文采用U-Pb同位素测年技术对扬子地块西部云南地区下奥陶世统红石崖组沉积岩开展了碎屑锆石原位LA-ICP-MSU-Pb年代学的研究。碎屑锆石U-Pb年龄谱特征表明，所采样品U-Pb年龄数据存在5个显著的年龄峰值，分别为524Ma、590Ma、830Ma、977Ma和2480Ma。本次研究获得了大量的泛非期锆石，反映出华南与冈瓦纳大陆之间的亲缘性。研究区与印度北部特提斯喜马拉雅、羌塘、澳大利亚西部及滇缅泰马地块具有相似的碎屑锆石年龄特征，表明这些地块的碎屑物质源区极为相似，华南与这些地块可能相邻或相距并不遥远。本文研究结果与前人根据其他地质资料得出的华南在早奥陶世期间位于澳大利亚的西北部，与滇缅泰马地块相邻这一认识相吻合。

英文摘要：

The configuration of Southern China within Gondwana has been of considerable controversy. In order to constrain the paleoposition of Southern China during the Early Paleozoic, this paper presents a study on in-situ U-Pb geochronology of detrital zircon from Hongshiya Formation, the Lower Ordovician in the western margin of the Yangtze Block. Results show five major age peaks, -524 Ma, -590 Ma, -830 Ma, -977 Ma and -2 480 Ma. The presence of Pan-African age populations suggests that Southern China had a strong affinity with Gondwana during the Early Ordovician. The age distribution of detrital zircons was obviously similar with that of Southern China, Tethyan Himalaya, Qiangtang, Western Australia, and Sihumasu, revealing that they might share a common source provenance and have adjacent relationships. Our results are consistent with the conclusion based on other geological data that South China had occupied a position on the Western Australia and been adjacent to Sibumasu during the Early Ordovician.