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（或造山作用）相关的大部分变形是沿着断层发生的，这些断层促进地壳水平缩短和垂直增厚，从而驱动造山。大多数研究山地系统（造山带）的研究重点是表征垂直于造山带结构纹理的结构、变质作用和地质年代学的变化。这在阐明控制山区系统发展的许多过程方面取得了广泛的成功。然而，使用这种传统方法仍然存在尚未解决的基本问题，例如调和整个山带的总收敛与地质记录中识别的总缩短之间的差异。喜马拉雅体系是印度板块和亚洲板块碰撞和汇聚的结果，最近的研究报告了局部地区的造山带平行流，垂直于预期的汇聚平行方向。量化物质的这种平面外运动可能有助于解决理解造山带方面的一些突出问题，例如上面提到的问题。喜马拉雅山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，但没有一个解释能够解释自洽模型中的所有观测结果。喜马拉雅山中已发现造山带平行流的地点直接位于印度板块的地形高点之上，而印度板块正被推向亚洲之下。这种关系导致了这样的假设：高于如此高点的增强压缩迫使物质通过造山带平行流横向逃逸到邻近区域。类似的地质关系也出现在努纳维克的元古代昂加瓦造山带和阿联酋暴露的白垩纪化石俯冲带中。喜马拉雅山、努纳维克山和阿联酋造山带平行流的性质将成为总部领导的多项调查的焦点。为了了解变形的条件、对称性、特征和速率的细节，这些项目将是多学科的，并为总部提供实践经验以及各种可直接转移的非常有价值的分析、项目管理和数据评估技术任何就业部门。本文提出的研究将有助于我的长期研究计划目标，即了解控制山脉发展的地质过程。至关重要的是，这项新研究将有助于量化会聚系统中流动的 3D 性质，目前该问题尚未得到充分研究，但对于开发造山作用的代表性热机械或模拟模型至关重要。这些模型可用于解释俯冲系统、相关地震灾害以及复杂变形区域的矿体分布。