Orogen parallel flow in convergent systems

汇聚系统中的造山带平行流

• 批准号: RGPIN-2021-02501
• 负责人: Larson, Kyle
• 金额: $ 4.44万
• 依托单位: University of British Columbia
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=761702
• 关键词: Orogen; parallel; flow; convergent; systems

Mountain belts typically mark zones where tectonic plates convergence. Most of the deformation associated with mountain building (or orogenesis) is taken up along faults that facilitate horizontal shortening and vertical thickening of the crust, which drives mountain building. Most studies that examine mountain systems (orogens) focus on characterizing changes in structure, metamorphism, and geochronology perpendicular to the structural grain of the orogen. This has been broadly successful in elucidating many of the processes that govern how a mountain system develops. Yet, there remain fundamental questions that have not been solved using this traditional approach, such as reconciling discrepancies in the total convergence across a mountain belt and total the shortening recognized in the geological record. Recent studies within the Himalayan system, the result of collision and convergence between the Indian and Asian plates, have reported local areas of orogen-parallel flow, perpendicular to the expected convergence-parallel direction. Quantifying this out-of-plane movement of material may help solve some of the outstanding issues in understanding orogens such as that mentioned above. Researchers in the Himalaya have offered a variety of different interpretations for the driving mechanisms of orogen-parallel flow, none of which explain all observations in a self-consistent model. The localities in which orogen-parallel flow has been recognized in the Himalaya directly overlie topographic highs in the Indian plate that is being thrust under Asia. This relationship leads to the hypothesis that enhanced compression above such highs forces lateral escape of material to adjacent areas through orogen-parallel flow. Similar geological relationships occur in the Proterozoic Ungava orogen of Nunavik and the Cretaceous fossil subduction zone exposed in the U.A.E. The nature of orogen-parallel flow in the Himalaya, Nunavik and U.A.E. will serve as the focus of multiple HQP-led investigations. In order to understand the details of the conditions, symmetry, characteristics and rates of deformation, the projects will be multi-disciplinary and provide HQP hands-on experience with a variety of highly valuable analytical, project management and data assessment techniques that are directly transferrable to any employment sector. The research proposed herein will contribute to my long-term research program goal of understanding the geological processes that govern how mountain belts develop. Critically, this new research will help quantify the 3D nature of flow in convergent systems, which, at present, is under-investigated, yet fundamental to developing representative thermo-mechanical or analogue models of orogenesis. Such models can be used to inform interpretations of subduction systems, and associated seismic hazards, and ore body distribution in complexly deformed regions.

山脉带通常标志着构造板块汇聚的区域。与造山(或造山)相关的大部分变形是沿着断层进行的，这些断层促进了地壳的水平缩短和垂直增厚，从而推动了造山。大多数研究山系(造山带)的研究集中于描述与造山带结构颗粒垂直的构造、变质作用和年代学的变化。这在阐明管理山地系统如何发展的许多过程方面取得了广泛的成功。然而，仍然有一些根本问题没有用这一传统方法解决，例如调和跨山脉带的总汇聚和地质记录中确认的总缩短之间的差异。最近在喜马拉雅系统内的研究，印度和亚洲板块碰撞和会聚的结果，报告了造山带平行流动的局部地区，垂直于预期的会聚-平行方向。对这种物质的平面外运动进行量化，可能有助于解决上述造山带方面的一些悬而未决的问题。喜马拉雅山脉的研究人员对造山带平行流的驱动机制提出了各种不同的解释，但没有一种解释能用自洽的模型解释所有的观测结果。喜马拉雅地区已发现造山带平行流动的地区直接位于印度板块的地形高地之上，印度板块正被推向亚洲下方。这种关系导致了这样一个假设，即在这样的高度之上加强压缩，迫使物质通过造山带平行流动横向逃逸到邻近地区。在努纳维克的元古界昂加瓦造山带和阿联酋发现的白垩纪化石俯冲带中也存在类似的地质关系。喜马拉雅、努纳维克和阿联酋造山带平行流动的性质将成为HQP领导的多项调查的重点。为了了解条件、对称性、特征和变形速率的细节，这些项目将是多学科的，并为HQP提供实践经验和各种非常有价值的分析、项目管理和数据评估技术，这些技术可以直接转移到任何就业部门。这里提出的研究将有助于我的长期研究计划目标，即了解支配山脉地带发展的地质过程。关键的是，这项新的研究将有助于量化会聚系统中流动的3D性质，目前这方面的研究还不够深入，但对于开发具有代表性的造山作用的热力学模型或模拟模型来说是至关重要的。这种模型可以用来解释俯冲系统和相关的地震灾害，以及复杂变形地区的矿体分布。