Rapid Miocene Thrust Propagation and Wholesale Basin Partitioning along the Central and Southern Andes, Argentina

综合分析沉积盆地演化、构造年代学、基岩年代学和盆地填充物将更好地定义阿根廷中西部安第斯褶皱冲断带和近前陆盆地的侵蚀掘出史、逆冲断层扩展史、构造沉降史和构造分区史。该项目的重点是沿着南部31-35度的安第斯山脉中部过渡到南部的三个关键区域横断面的南北变化。虽然现有的证据表明，新生代褶皱-冲断变形向克拉通快速东进的时期，但时空关系尚未得到很好的解决。更不清楚的是，纳斯卡俯冲板块的南北几何形态、安第斯火山弧的岩浆历史以及继承的前新生代构造的形态，在多大程度上影响了构造和沉积过程。该野外调查将生成沉积、构造和年代学数据集，以比较和对比安第斯山脉东部弧后地区不同锋面构造带的详细演化，以评估前陆盆地充填物的缩短和侵蚀再循环的进展。从安第斯山脉中部到南部的过渡包括现代平板俯冲的最好例子，以及通过重新激活先前存在的裂谷构造的反转构造的关键例子。这种活动大陆边缘提供了一个很好的机会来研究地壳快速推进的缩短和相邻前陆盆地的大规模分割的潜在控制因素，这一过程被认为是其他会聚造山系的过程。对东部弧后带盆地发育和基岩发掘的详细研究，将有助于我们探索构造反转和岩浆脉冲在变形前沿推进中的潜在重要性，以及平板俯冲导致的上层岩石圈动态响应和地表表达。这将进一步加深对安第斯构造的理解，并提供有价值的见解，可以外推到其他汇聚系统中当前和过去的平板俯冲区域。该项目将支持一名教职员工、一名博士后学者以及德克萨斯大学奥斯汀分校的研究生和本科生进行实地和实验室调查。这些工作将与阿根廷学术机构和碳氢化合物行业的区域专家的工作相结合。此计划将促进新的国际学术与产业合作，并建立学术交流访问的框架，以提供互惠的国际学习经验和促进长期的研究合作。该项目还将通过德克萨斯大学奥斯汀分校杰克逊地球科学学院的现有项目，包括GEOFORCE项目，支持公众宣传和教育。支持与该项目相关的国际活动的资金由美国国家科学基金会国际科学与工程办公室提供。

Integrated analyses of sedimentary basin evolution, structural timing, and geochronology of bedrock and basin fill will better define the history of erosional exhumation, thrust-fault propagation, tectonic subsidence, and structural partitioning of the Andean fold-thrust belt and proximal foreland basin in west-central Argentina. The project focuses on the delineation of north-south variations among three key regional transects along the transition from the central to southern Andes at 31-35 degrees south. Although available evidence suggests periods of rapid eastward advance of Cenozoic fold-thrust deformation toward the craton, the temporal and spatial relationships are not well resolved. Further unclear is the degree to which the structural and sedimentary processes have been influenced by major north-south contrasts in the geometry of the subducted Nazca slab, the magmatic history of the Andean volcanic arc, and the configuration of inherited pre-Cenozoic structures. This field-based investigation will generate sedimentary, structural, and chronological datasets to compare and contrast the detailed evolution of the distinct frontal tectonic zones in the eastern retro-arc region of the Andes Mountains in order to evaluate the advance of shortening and erosional recycling of foreland basin fill.The transition from the central to southern Andes includes the best-understood example of modern flat-slab subduction and a key example of inversion tectonics by reactivation of preexisting rift structures. This active continental margin provides an excellent opportunity to examine the potential controls on rapid advance of crustal shortening and wholesale partitioning of adjacent foreland basins, a process suggested for other convergent orogenic systems. A detailed investigation of basin development and bedrock exhumation in the eastern retro-arc zones will allow us to explore the potential importance of structural inversion and magmatic pulses in the advance of the deformation front, as well as the dynamic upper lithospheric response and surface expression, or lack thereof, resulting from flat-slab subduction. This will further understanding of Andean tectonics and provide valuable insights that can be extrapolated to regions of current and past flat-slab subduction in other convergent systems.The project will support field and laboratory investigations by a faculty member, a postdoctoral scholar, and graduate and undergraduate students from the University of Texas at Austin. These efforts will be integrated with those of regional experts from academic institutions and the hydrocarbon industry in Argentina. This project will promote new international academic-industry collaborations and establish the framework for academic exchange visits, in order to providing reciprocal international learning experiences and facilitating longer term research collaborations. The project will also support public outreach and education through existing programs in the Jackson School of Geosciences at UT-Austin, including the GEOFORCE program.Funds to support the international activities associated with this project are being provided by the NSF Office of International Science and Engineering.