滇西地区夷平面变形及其反映的第四纪构造运动

滇西地区广泛发育一级上新世夷平面。夷平面普遍受到两种变形,一种是大面积的掀斜变形,夷平面高度由西北向东南方向递减;另一种为断裂变形,夷平面呈地堑式下降或地垒式上升。 如果以夷平面为第四纪构造运动标志,那么,自上新世末朗以来,滇西地区垂直上升幅度为3500～400m;滇西几条活断层的垂直位移幅度分别是,剑川断裂1650～500m,怒江断裂1850m,腾冲 梁河盆地南北向、北东向断裂分别为850m和1300m。

DEFORMATION OF PLANATION SURFACE IN WEST YUNNAN AND ITS SIGNIFICANCE IN QUATERNARY TECTONIC MOVEMENT

In west Yunnan there develops widely the lst order planation surface of the pliocene which is characterized mainly by its smooth reliefjthe ancient residual landform and the development of terra rossa residuum and alluvium on it. The planation surface in west Yunnan was universally deformed, and the deformation is generally belonging to two types; one is the large area tilting deformation.,the height of planation surface decreases from northwest to southeast, the original elevation of the planation surface in 1000m, the amplitude of uplifting decreased since the late Pliocene from northwest to southeast, i.e. from 3500 m to 400m; the another one is the faulting deformation with the disintegration of the pfenation surface as its main expression and this was principally shown as graben type subsidence and horst type uplifting, so both fault block mountains and graben basins were formed (or it might lead to the further development of the Pliocene fault basin), and there in the periphery of basin the 1st to 3rd order step-formed fault terrace were formed. By using the planation surface as a mark, then the vertical displacement of active faults since the late Pliocene may be calculated, the Jianchuan fault was 1650~500 m from south to north; the Nujiang fault in Daojie basin was 1850m; the S ?Nward and the NEward faults in Tengchong ?Lianghe basin was 850 m and 1300 m respectively.