中文摘要：

利用构造地貌学的研究方法，基于数字高程模型（DEM）数据对四川盆地东部大巴山和川东一湘鄂西弧形带的地形特征和水系样式进行深入剖析，结果表明：1）弧形构造变形机制控制了大尺度地形特征。在大巴山弧形带的逆冲推覆机制作用下形成高海拔一高起伏地形，而在川东-湘鄂西弧形带的拆离滑脱机制作用下形成高海拔一低起伏地形。2）弧形构造扩展模式控制了水系样式。大巴山弧形带“推土机”式扩展模式导致山脉前缘发育横向水系，而川东-湘鄂西弧形带则表现为“三维”构造扩展，即在垂直构造走向递进式扩展的同时，还伴随有平行构造走向从中央向两侧的扩展，此种模式导致弧形带发育由中央分水岭分隔的纵向水系。弧形构造控制的地形和水系发育规律还暗示了长江三峡的成因。长江三峡很可能是在川东一湘鄂西弧形构造变形阶段首先发育先成河，而后由于构造叠加作用伴随河流下切而形成的深切峡谷。

英文摘要：

Based on DEM（ Digital Elevation Model） ,the topography characters and drainage patterns are analyzed in two arcuate fold-thrust belts in eastern Sichuan basin, the Dabashan fold-thrust belt and the eastern Sichuan-western Hubei and Hunan fold-thrust belt. They are both formed as thin-skinned fold-thrust belts during Late Jurassic to Cretaceous,and involved the Paleozoic platform sequence and Late Triassic-Jurassic foreland sequence. Our results indicate that 1 ） the ancient structural deformation control the distribution of the large-scale topography today in the two arcuate fold-thrust belts. The high-elevation, high-relief topography in Dabashan fold-thrust belt is dominantly related to the SW oriented thrusting structures established during Late Jurassic to Early Cretaceous. In contrast,the high-elevation,low-relief topography in eastern Sichuan-western Hubei and Hunan fold-thrust belt is highly related to the NW oriented thin-skinned folding structures established during Late Cretaceous; 2）the kinematics of thrusting and folding propagation control the present-day drainage pattern in the two arcuate fold-thrust belts. The Dabashan fold-thrust belt is dominated by range-parallel rivers developed during SW oriented thrusting propagation, while the eastern Sichuan-western Hubei and Hunan fold-thrust belt is dominated by range-transverse rivers developed during lateral propagation of the fold-thrust belt. Such kinematic of lateral propagation caused the along- strike uplift first occurring on the ＂midline＂ of the eastern Sichuan-western Hubei and Hunan fold-thrust belt, leading to a ＂midline＂ drainage divide between the SW-flowing and NE-flowing range-parallel rivers. Our results also provide new clues for Yangtze River evolution in the Three Gorges regions. We interpret this segment of Yangtze River to be an antecedent range-parallel river that was formed during Early Cretaceous E-W trending deformation. The Gorges could not have been cut across until the late stage NE trending deformation occurr