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

综合分析沉积盆地的演化，结构定时，基岩和盆地填充的地质年代学，将更好地确定历史的侵蚀剥露，逆冲断层传播，构造沉降，和结构划分的安第斯褶皱冲断带和近端前陆盆地在中西部阿根廷。 该项目的重点是划定从中部到南部安第斯山脉南纬31-35度过渡沿着三个主要区域断面的南北变化。 尽管已有证据表明新生代褶皱-逆冲变形向克拉通快速东进的时期，但时间和空间关系并没有得到很好的解决。 进一步不清楚的是，在何种程度上的结构和沉积过程已受到影响的主要南北对比的几何形状的纳斯卡板块，安第斯火山弧的岩浆历史，并继承前新生代结构的配置。 这种基于实地的调查将产生沉积，结构，和年代学数据，比较和对比安第斯山脉弧后东部地区不同前缘构造带的详细演化，以评估前陆盆地充填缩短和侵蚀再循环的进展。从中部到南部的过渡安第斯山脉包括现代平坦的最好理解的例子，板块俯冲和反转构造的一个重要例子，通过重新激活先前存在的裂谷结构。 这种活动大陆边缘提供了一个很好的机会来检查潜在的控制快速推进的地壳缩短和批发分割相邻的前陆盆地，一个过程中建议其他会聚造山系统。 详细调查盆地的发展和基岩折返在东部弧后区将使我们能够探索潜在的重要性，结构反转和岩浆脉冲的变形前，以及动态的上部岩石圈的响应和表面的表达，或缺乏，导致平板俯冲。 这将进一步了解安第斯构造，并提供有价值的见解，可以外推到当前和过去的平板俯冲在其他收敛system.The项目将支持现场和实验室调查的教师，博士后学者，研究生和本科生从得克萨斯大学奥斯汀分校。 这些努力将与来自阿根廷学术机构和碳氢化合物行业的区域专家的努力相结合。 该项目将促进新的国际学术-产业合作，并建立学术交流访问框架，以提供互惠的国际学习经验，并促进长期的研究合作。该项目还将通过德州大学奥斯汀分校杰克逊地球科学学院的现有项目，包括GEFORCE项目，支持公众宣传和教育，支持与该项目有关的国际活动的资金由NSF国际科学和工程办公室提供。

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.