Analysis of the Significance of Erosional Denudation on the Geometrical and Stratigraphic Evolution of Foreland Basins and on Strain Partitioning in their Orogens

9614286近年来，人们对约旦前陆盆地进行了广泛的研究，以探讨造山带地壳增厚与邻近前陆盆地的地层和几何响应之间的关系。由于前陆盆地总挠度的60%可能是由泥沙负荷引起的，因此由于腹地侵蚀剥蚀速率和模式的变化而引起的泥沙通量的时空变化有可能显著影响前陆盆地的几何和地层演化。此外，根据临界锥楔模型，造山带内不同的侵蚀剥蚀速率可能控制应变分配，进而影响前陆盆地的几何演化。我们建议探讨侵蚀剥蚀速率的时空变化对Molasse和Bermejo盆地几何和地层演化以及阿尔卑斯山（瑞士）和普雷科迪勒拉（阿根廷）的应变分配的影响。这些系统非常适合我们的目标，因为有广泛的可用数据，因为它们代表了剥蚀/分散端元。侵蚀剥蚀率将从阿尔卑斯山的冷却和变质年龄的密集数据集中编制，并通过将内部排水的Bermejo盆地中保存的沉积物体积恢复到其特定的来源地形。这些数据将与前陆盆地的沉降史进行比较，这将使我们认识到沉积物通量对Molasse盆地和Bermejo盆地演化的重要性。同样，仔细的三维沉降分析将使我们能够比较内部排水的Bermejo盆地和开放的Molasse盆地的沉降模式。比较和对比沉降历史、沉积物通量和相的进退速率将使我们能够批判性地评估开放盆地是否比封闭盆地更容易形成不整合面。此外，我们建议探讨盆地地层学对构造事件的敏感性是否取决于主要沉积物源区的位置。利用Strata2.11进行地层模拟，对盆地的相、几何演化进行可视化。使用该软件，我们将能够测试沉积物通量而不是构造沉降和/或海平面上升变化导致了Molasse盆地的回归和海侵。此外，将2.11地层应用于Molasse和Bermejo盆地，可以探讨不同泥沙通量对河流体系不整合形成的意义。将侵蚀剥蚀率的时空变化与造山带的应变分配进行比较，将使我们能够批判性地评估侵蚀是否像临界锥楔模型预测的那样，显著地控制了冲断运动的顺序。我们建议通过对比两个剥蚀端段来分析气候和岩石可蚀性对造山带逆冲年代学的影响。

9614286 Jordan Foreland basins have been studied extensively I the last years to explore the relationships between crustal thickening in the orogen and the stratigraphic and geometrical response of the adjacent foreland basin. Since 60% of the total deflection of foreland basins may be due to the sediment load, temporal and spatial variations in sediment flux due to changing erosional denudation rates and patterns in the hinterland have a great potential to significantly affect the geometrical and stratigraphic evolution of foreland basins. Furthermore, as revealed by critical taper wedge models, variable erosional denudation rates in the orogen are likely to control strain partitioning, which in turn affects the geometrical evolution of foreland basins. We propose to explore the influence of temporal and spatial variations of erosional denudation rates on the geometrical and stratigraphic evolution of the Molasse and Bermejo Basins and on strain partitioning in the Alps (Switzerland) and the Precordillera (Argentina). These systems are ideally suited to our objectives because of the extensive data available and because they represent denudation/dispersion end members. The erosional denudation rates will be compiled from the dense data set of cooling and metamorphic ages in the Alps, and by restoring the volumes of sediment preserved in the internally drained Bermejo Basin to their specific source terrains. These data will be compared with the subsidence histories of the foreland basins determined by backstripping, which will allow us to recognize the importance of sediment flux on the evolution of the Molasse and the Bermejo Basins. Similarly, a careful three dimensional subsidence analysis will allow us to compare the subsidence patterns of the internally drained Bermejo Basin and the open Molasse Basin. Comparing and contrasting the subsidence histories, the sediment flux, and progradation/retreat rates of facies will allow us to critically evaluate whether unconformities are mo re likely to form in open than in closed basins. In addition, we propose to explore whether the sensitivity of the basin stratigraphy to tectonic episodes depends on the location of the principle sediment source area. The evolution of facies and geometries of the basins will be visualized by stratigraphic simulation with Strata2.11. Using this software, we will be able to test whether sediment flux rather than tectonic subsidence and/or eustatic sea level changes caused the regressions and transgressions in the Molasse Basin. Furthurmore, applying Strata2.11 to the Molasse and Bermejo Basins, we can explore the significance of varying sediment flux on the generation of unconformities in fluvial systems. Comparing the temporal and spatial variations of erosional denudation rates with strain partitioning in the orogens will enable us to critically evaluate whether erosion significantly controlled the sequence of thrust motions as predicted by critical taper wedge models. We propose to analyze how climate and erodibility of rocks affect the chronology of thrusting in orogens by contrasting the two denudation end members.