Neogene to Quaternary tectono-geomorphic evolution and paleo-hydrology of the South Central Andes, NW Argentina

阿根廷中南部安第斯山脉是研究活跃的俯冲造山带构造和气候演化的理想地点。作为安第斯山脉不可分割的一部分，位于普纳高原造山带边缘的山间盆地沉积地层记录了东扩造山带的构造和气候时空特征。了解地形屏障抬高造成的水文和生态变化对于重建这种过程至关重要。利用山间盆地和前陆沉积物中氧(O)和氢(H)的稳定同位素浓度，我们提出了一种多代理同位素研究，该研究需要研究海拔变化、古气候和沉积特征。这将对理解非碰撞造山至关重要，并将提高我们对侧向造山高原发育及其对环境参数的影响的理解。我们将通过：a)从溪水和雨水、土壤和植物中获得现代稳定同位素数据；b)通过从盆地记录中提取的脂类生物标志物的氢同位素特征来破译水文和气候变化；c)利用火山玻璃碎片的同位素特征来评估海拔变化及其对地形降水的影响；以及d)结合我们的结果来理解前陆分段期间的侧向造山生长模式以及随后的气候和沉积系统的变化。

The South Central Andes of Argentina are ideal to study the tectonic and climatic evolution of an actively growing subduction orogen. As an integral part of the Andes, sedimentary strata in intermontane basins straddling the margin of the intraorogenic Puna Plateau record valuable information on spatiotemporal characteristics of tectonism and climate of the eastward propagating orogen. Understanding the hydrologic and ecological changes caused by the uplift of orographic barriers is crucial for reconstructing such processes. We propose a multiproxy isotope study that entails the study of elevation changes, paleoclimate, and sedimentation characteristics, by utilizing stable isotope concentrations of oxygen (O) and hydrogen (H) from sediments in the intermontane basins and the foreland. This will be of paramount importance to understanding non-collisional mountain building and will improve our understanding of lateral orogenic plateau development and its influence on environmental parameters. We will gain insights into these complex issues by: a) obtaining modern stable isotope data from stream- and rainwater, soils, and plants; b) deciphering hydrologic and climatic changes through the H-isotope signature of lipid biomarkers extracted from the basin record; c) evaluating elevation changes and their effects on orographic precipitation using the isotopic signature of volcanic glass shards; and d) combining our results to understand the patterns of lateral orogenic growth during foreland segmentation and ensuing changes in the climate and depositional systems.