Kinematic Response of the Argentine Precordillera Fold-and-thrust Belt to Erosion

最近，科学家们提出，板块构造过程可能受到侵蚀的强烈影响。这意味着作用于地球表面的过程可能与作用于地球内部的过程相耦合。该项目将使用模拟模型来研究侵蚀可能对阿根廷中部Precordillera褶皱和冲断带的运动发育产生的影响。在这里，大量的野外数据限制了褶皱冲断带的运动学，在科迪勒拉主断层、科迪勒拉前缘断层和前科迪勒拉断层更南的工作表明，侵蚀可能对褶皱冲断带的几何形状演化起着重要的控制作用。本项目使用解析公式和比例沙盒模拟模型来了解不同侵蚀条件下褶皱冲断带的运动学演化。将使用造山带尺度侵蚀规则，将侵蚀速率与内在因素（如岩石可蚀性的岩性差异）和外在因素（如气候变化）联系起来。这些结果将与观察到的褶皱冲断带运动学进行比较，以推断侵蚀在山带发育中所起的作用。此外，将执行一系列正演模拟模型，这些模型考虑了与具有不同侵蚀阻力的岩石类型暴露和长期气候变化相关的侵蚀条件的时间变化。这种多层次的方法将首先提供对可能受到侵蚀强烈影响的前科迪勒拉褶皱冲断带运动学方面的见解，然后将这些具体结果扩展到一系列变化的侵蚀条件，这些条件可能与褶皱冲断带中不同岩石类型的暴露和全球气候变化有关。深层地球过程可能与浅层地球过程有关的发现，也许是最近对板块构造理论最重要的贡献之一。如果这是真的，这一概念将缓和对过去和现在山带活动的解释，并可能引导地球科学家以新的方式重新解释地质记录的许多方面。目前，大多数寻求建立这种新范式的研究都集中在将一般数值模型结果与实地观测结果进行定性比较上。这项研究将首次将特定的模型预测与经过充分研究的山带进行比较，以确定地表过程是否对解释其发展是必要的。这项研究的结果将有助于建立深层地球和地表过程之间的联系，并了解这些联系在不同的构造和侵蚀环境中可能有多强。这项研究包括一个由来自美国、委内瑞拉和加拿大的科学家组成的国际团队，并将通过外展项目促进代表性不足的高中生的教育。

Recently, scientists have proposed that plate tectonic processes may be strongly influenced by erosion. This implies that processes acting over the surface of the Earth may be coupled to those acting within its interior. This project will use analogue models to study the influence that erosion may have played on the kinematic development of the Precordillera fold-and-thrust belt of central Argentina. Here, extensive field data constrain the kinematics of the fold-and-thrust belt, and work farther south in the Cordillera Principal, Cordillera Frontal, and Precordillera indicates that erosion may exert an important control on the evolving geometry of the fold-and-thrust. This project uses analytical formulations and scaled sandbox analogue models to understand how the kinematics of the fold-and-thrust belt evolve under different erosional conditions. An orogen-scale erosion rule that relates erosion rates to intrinsic factors, such as lithologic differences in rock erodibility, and extrinsic factors, such as climate changes will be used. These results will be compared to the observed kinematics of the fold-and-thrust belt to deduce the role that erosion played in the mountain belt''s development. In addition, a series of forward analogue models that consider temporal changes in erosional conditions associated with the exposure of rock types with varying resistance to erosion and long-time-period changes in climate will be performed. This multi-tiered approach will first provide insight into those aspects of the kinematics of the Precordillera fold-and-thrust belt that may be strongly influenced by erosion, and then will expand these specific results to a range of changing erosional conditions that might be related to exposure of different rock types in fold-and-thrust belts and global climate changes.The discovery that deep earth processes may be linked to those of the shallow earth is perhaps one of the most important recent contributions to the theory of plate tectonics. If true, this concept will temper interpretations of the past and current operation of mountain belts, and may lead geoscientists to reinterpret many aspects of the geologic record in new ways. Currently, most studies that seek to establish this new paradigm have concentrated their efforts on qualitative comparisons of general numerical model results with scare field observations. This study will be the first to compare specific model predictions to a well-studied mountain belt to determine if surface processes are necessary to explain its development. Results of this research will help to establish this linkage between deep earth and surface processes, and to understand how strong these links may be in different tectonic and erosional environments. The study includes an international team of scientists from the United States, Venezuela, and Canada, and will promote the education of under-represented high school students through outreach programs.