Early Tertiary orogenic evolution of the southern Central Andes as reflected by the detrital record preserved in the Puna Plateau and Eastern Cordillera of NW Argentina

当今地球科学中的关键科学问题之一集中在作用于地球深层(岩石圈)的过程与作用于浅层(地壳)和地表的过程之间的关系。目前尚不清楚这些进程是否或如何共同作用，以及是否存在耦合。如果我们想要了解地球动力学，了解地球深部与地表过程之间的关系是至关重要的。山脉和相关的前陆盆地是这种复杂相互作用的结果，为研究内生和外生力量之间的关系提供了一个天然的实验室。前陆盆地系统在成因上与其邻近的山脉相联系，并提供关于地球深部过程(沉降)和地表过程(沉积物沉积和风化)的独特、长期的信息档案。前陆盆地的沉降量、沉积充填体的形状和碎屑沉积物的来源取决于地形载荷的位置和大小、沉积过程中作用的压应力模式以及源盆系统的类型、地形和气候。保存在阿根廷西北部普纳高原和东部科迪勒拉的沉积盆地提供了与安第斯山脉建造有关的最早的挤压变形记录之一。这些盆地包含4公里厚的古近纪碎屑沉积，暴露得非常好。对玻利维亚中南部(阿尔蒂普诺)现代沉积盆地的研究表明，古新世已经开始形成前陆盆地系统，即收缩变形，大量前陆岩石圈被推送到安第斯地壳下，导致造山带的形成。对阿根廷西北部时间等值盆地的多学科研究将提供新的数据，以便对这一模型进行测试和可能的验证。这反过来将使我们能够量化安第斯山脉这一部分在关键时期(即古近纪)的原始古地理、折返、地貌、气候和盆地形成机制，这对我们理解与普纳-阿尔蒂普诺高原和东科迪勒拉系统有关的早第三纪山脉建造有很大帮助。

One of the key scientific problems in Geosciences today is centred on the relationships between processes acting in the deep earth (lithosphere) versus processes acting at shallower levels (in the crust) and at the surface. It is not clear if or how such processes are acting together and whether or not a coupling exists. Understanding the relationships between deep Earth and surficial processes is of fundamental importance if we want to understand Earth dynamics. Mountain belts and related foreland basins are the result of this complex interaction and provide a natural laboratory to investigate the relationships between endogenic and exogenic forces. A foreland basin system is genetically linked to its adjacent mountain belt and provides unique, long-term archives of information about deep Earth processes (subsidence) and surficial processes (sediment deposition and weathering). The magnitude of subsidence, the shape of the sedimentary fill and the source of detrital sediments in foreland basins depends on the location and size of the topographic load, the mode of compressional stresses acting during sedimentation and on the type, relief and climate of the source-basin system. Sedimentary basins preserved within the Puna Plateau and Eastern Cordillera in NW Argentina provide one of the earliest records of compressional deformation associated with Andean mountain building. These basins contain >4 km-thick Paleogene clastic sediments that are exceptionally well exposed. Studies in contemporary sedimentary basins in southern central Bolivia (Altiplano) lead to the proposition that a foreland basin system, i.e. contractional deformation, already started in the Paleocene and that a significant amount of foreland lithosphere was thrusted underneath the Andean crust leading to the building of the orogenic belt. A multidisciplinary study of time equivalent basins in NW Argentina shall provide new data that will allow testing and potential validation of this model. This in turn will permit quantification of source paleogeography, exhumation, relief, climate and mechanisms of basin formation in this part of the Andes, in a key time that is the Paleogene, contributing greatly to our understanding of mountain building associated to the Puna-Altiplano Plateau and Eastern Cordillera system in the early Tertiary.