Abstract Analysis of several morphotectonic tools (longitudinal river profiles, knickpoints, swath profiles, and geomorphic indices) together with geomorphological, lithological, and structural data provided objective and quantifiable elements to improve the knowledge of the Quaternary tectonic activity in a region. In this study, we analyzed and compared two large intermountain basins located in the Precordillera of the Central Andes of Argentina. Local distortions in longitudinal river profiles and river patterns may reflect resistant lithology, an increase in shear stress, or differential surface uplift. Both basins have similar shapes, although one mirrors the other producing a large-scale broom-shaped drainage pattern. The values of the Asymmetry Factor and Transverse Topographic Symmetry Factor show opposite signs and almost identical values, suggesting that both basins have mirror symmetry independently of order and scale. The asymmetry in both basins would be a result of the progressive migration of the Andean orogenic front towards the east. Knickpoints were mainly associated with resistant rocks, faults with the scarp facing upstream, or both. In the reaches where the rivers flow across areas with presumed higher rates of uplift, we observed a reduction in the width of the active channel belt by lateral confinement and river pattern changes. The results presented in this paper constitute one of the first attempts to apply geomorphic indices to large drainage basins in the Precordillera fold-and-thrust belt.

中文翻译：

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阿根廷中部安第斯山脉前科迪勒拉褶皱冲断带控制的圣胡安河两个轴向支流盆地的形态构造分析

摘要 对几种形态构造工具（纵向河流剖面、断点、条带剖面和地貌指数）以及地貌、岩性和构造数据的分析提供了客观和可量化的元素，以提高对一个地区第四纪构造活动的了解。在这项研究中，我们分析和比较了位于阿根廷中部安第斯山脉 Precordillera 的两个大型山间盆地。纵向河流剖面和河流格局的局部扭曲可能反映了抗性岩性、剪切应力的增加或不同的表面隆起。两个盆地具有相似的形状，尽管一个反射另一个产生大规模的扫帚状排水模式。不对称因子和横向地形对称因子的值显示相反的符号和几乎相同的值，这表明两个盆地都具有独立于秩序和规模的镜像对称。两个盆地的不对称性是安第斯造山带向东逐渐迁移的结果。断点主要与抗性岩石、陡崖面向上游的断层有关，或两者兼而有之。在河流流经推定较高抬升率区域的河段，我们观察到活动河道带的宽度因侧向限制和河流格局变化而减少。本文提出的结果是将地貌指数应用于 Precordillera 褶皱冲断带大型流域盆地的首批尝试之一。两个盆地的不对称性是安第斯造山带向东逐渐迁移的结果。断点主要与抗性岩石、陡崖面向上游的断层有关，或两者兼而有之。在河流流经推定较高抬升率区域的河段，我们观察到活动河道带的宽度因侧向限制和河流格局变化而减少。本文提出的结果是将地貌指数应用于 Precordillera 褶皱冲断带大型流域盆地的首批尝试之一。两个盆地的不对称性是安第斯造山带向东逐渐迁移的结果。断点主要与抗性岩石、陡崖面向上游的断层有关，或两者兼而有之。在河流流经推定较高抬升率区域的河段，我们观察到活动河道带的宽度因侧向限制和河流格局变化而减少。本文提出的结果是将地貌指数应用于 Precordillera 褶皱冲断带大型流域盆地的首批尝试之一。我们观察到横向限制和河流格局变化导致活动河道带的宽度减少。本文提出的结果是将地貌指数应用于 Precordillera 褶皱冲断带大型流域盆地的首批尝试之一。我们观察到横向限制和河流格局变化导致活动河道带的宽度减少。本文提出的结果是将地貌指数应用于 Precordillera 褶皱冲断带大型流域盆地的首批尝试之一。