南盘江上游河网纵剖面图像及其构造指示意义

THE DRAINAGE NETWORK AND LONGITUDINAL PROFILE IMAGE （DNLPI） OF NANPANGJIANG RIVER UPSTREAM CATCHMENT AND ITS TECTONIC IMPLICATION

由红河断裂带和小江断裂带（鲜水河-小江断裂带）围限的川滇块体是亚洲大陆晚新生代被挤出的众多块体之一。南盘江上游流域跨越了川滇块体以及前人推测的由红河断裂带活动形成的滇东“压缩”变形区。本文选择南盘江上游流域作为研究区，试图通过河流地貌的方法研究川滇块体的挤出活动对剧边地区的影响以及识别滇东“压缩”变形区足否存在。使用DLR（德国宇航中心）数字高程数据制作了该流域的河网纵剖面图像，并通过图像预分析（分析岩性、人类工程以及灾害事件的影响）和野外凋查后进行构造解译。解译的结果显示：1）流域内存存4个构造掀斜区（W区为华溪河流域、S区为泸江流域、E1区为甸溪河中部和E2区为中和营河流域）和1个局部整体抬升区（M区为本研究区中部），其中IS区和M区与现今地壳垂直肜变速率图像有相似的活动表现，s区保持自南西向北东倾斜特征，M区保持整体抬升特征；2）流域的东南部存在一条北东向的佝造差异抬升分界线（LI）；3）E1区仔在一个差速活动（非同步活动）的左行左阶断裂系。研究结果表明，断层差速活动（非同步活动）是青藏高原东南缘构造变形中的一种重要调节机制；滇东“压缩”变形区是存在的，且与小江断裂带关系密切，但其范围没有前人推测的那么大；S区的掀斜抬升活动与红河断裂带的活动相关，并具有某些继承性特征。

The Chuandian block which bounds by the Red River fault zone and the Xiaojiang fault zone （Xianshuihe- Xiaojiang fault zone） is one of the Asian crust blocks that extruded in Late Cenozoic. The Nanpanjiang River upstream catchment spans the Chuandian block and the suspected ＂compression＂ deformation zone by the formers where relates to the activities of the Red River fault zone. In this paper, the Nanpanjiang River upstream catchment is chosen as the study area. We try to use the fluvial geomorphological method to study how the surrounding areas are influenced by the Chuandian block extrusion, and to distinguish whether the ＂compression＂ deformation zone exists or not. The DLR （Deutsches Zentrum far Luft-und Raumfahrt） digital elevation data is used to make the drainage network and longitudinal profile image （DNLPI） of the catchment. The image is interpreted after pre- analysis （analyzed the influence from lithology, human engineering and hazard event） and field investigation. The results are as follows ： （1） Four tectonic tilting areas （W area in Huaxi River catchment, S area in Lujiang River catchment, E1 area in the middle of Dianxihe River catchment and E2 area in Zhongheyinghe River catchment） and one local integral uplift area （M area, in middle of study area） are in the catchment, and the S area and M area keep the similar activities in the recent vertical crustal deformation where the S area is tilting from southwest to northeast and the M area remains integral uplift. （2） A NE trending different uplift boundary （L1） exists in the southeastern catchment. （3） A differential activity （asynchronous activity） left-lateral step fault system is existed in E1 area. After discussion, we consider that the fault differential activity （asynchronous activity） is an important regulation mechanism of tectonic deformation in the southeast margin of the Tibetan Plateau. The ＂compression＂ deformation zone in east Yunnan is existed and has closed correspondence to Xiaojiang fault zone, but the range may be smaller than the precious speculation. The tilting of the S area are closely related to the activities of the Red River fault zone, and also with some inherited characteristics.