Collaborative Research: Late Cretaceous-Tertiary Foreland Basin Evolution in the Eastern Cordillera of Southern Bolivia

[9804680]一般认为，沿南美洲西海岸的弧-陆相互作用涉及到主要的地壳缩短，这种缩短既使地壳增厚，又使陆地表面的高程在增厚的地壳上升高，并在前陆位置形成盆地。然而，玻利维亚至少有两个时期的地壳增厚，只有较年轻的一个得到了记录。更早时期（晚白垩世至中第三纪）的逆冲和前陆盆地演化几乎没有记录，但需要评估总的缩短，并了解当前地形和同造山矿床的起源。这个项目将研究这些沉积物，以检验关于它们起源的两种假设。研究结果有望在这些假设之间进行检验，并允许对安第斯山脉和其他弧后褶皱冲断带（如北美科迪勒拉）进行严格的比较。

9804680 DeCelles It is generally acknowledged that the arc-continental interactions along the western coast of South America has involved major crustal shortening that has both thickened the crust and raised the elevation of the land surface over the thickened crust and formed basins in the foreland position. However, there are at least two periods of crustal thickening in Bolivia, and only the younger one has received documentation. The older (late Cretaceous to mid tertiary) episode of thrusting and foreland basin evolution remains virtually undocumented, yet is required to assess total shortening and to understand the origin of the present topography and syn orogenic deposits. This project will study these sediments in order to test two hypotheses for their origin. The results are expected to test between these hypotheses and also allow for a rigorous comparison between the Andes and other retroarc fold-thrust belts, such as the North American Cordillera.