红河断裂带中南段上新世以来构造隆升及成因

Tectonic Uplift and Its Regime in the Central Southern Segment of the Red River Fault Zone Since Pliocene

在数字高程模型（DEM）数据处理和前人磷灰石裂变径迹测年（AFT）数据的基础上,分析和识别了红河断裂带中南段（弥渡至河口段）夷平面和河流阶地的展布特征,对断裂带两盘的构造地貌进行了定量、半定量研究。研究表明,弥渡-元江段、红河-河口段南西盘夷平面高于北东盘150-840m,元江-红河段北东盘夷平面高于南西盘140-230m。红河断裂带中南段经历了7.36-11.9、3.6-4.9、1.6-2.5Ma 3个主要构造活动期次。估算了元江-红河段上新世晚期以来的隆升速率,南西盘为1.38-1.53mm/a,北东盘为1.46-1.59mm/a。红河断裂带元江-红河段北东盘处于小江断裂带和红河断裂带交汇区,其构造隆升是后二者共同作用的结果。

Based on processing of the DEM data and apatite fission track data,the authors analysed and identified the distribution characteristics of the river terraces and planation surfaces in the central southern segment of the Red River fault zone（from Midu to Hekou）,and conducted quantitative and semiquantitative studies of the morphotectonic features of two plates of the Red River fault zone.Researches show that Red River fault zone exhibits about 150-840 m vertical displacement with uplifting on its southwestern block and subsiding on the northeastern block,from Midu to Yuanjiang and Honghe to Hekou,and 140-230mvertical displacement with uplifting on its northeastern block and subsiding on the southwestern block,from Yuanjiang to Honghe.The Red River fault zone has undergone three dislocations in 1.6-2.5、3.6-4.9and 7.36-11.9 Ma.Uplift rates of Red River fault zone（from Yuanjiang to Honghe）have been estimated based on AFT data and river terraces：the uplift rates of southwestern side since the late Pliocene was 1.38-1.53mm/a and northeastern side was 1.46-1.59mm/a.The tectonic uplift at northeastern side of the Red River fault zone（from Yuanjiang to Honghe）is the result of the interaction between the Xiaojiang fault zone and the Red River fault zone.