Collaborative Research: How and when did the Mongolian Altai (de-)form? Implications for intracontinental deformation

合作研究：蒙古阿尔泰山是如何以及何时形成的？

• 批准号: 2111939
• 负责人: Ryan Leary
• 金额: $ 67.69万
• 依托单位: New Mexico Institute of Mining and Technology
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-08-01 至 2024-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2111939&HistoricalAwards=false
• 关键词: Collaborative; Research; How; when; did

The Mongolian Altai are an approximately 2000 km-long mountain range in western Mongolia that are part of a vast mountainous region in central Asia referred to as the Central Asian Orogenic Belt. Understanding how a mountain system that is located 1000 km from a modern tectonic plate boundary originally formed is important as the Altai play an important role in regulating Asian climate and biodiversity and in controlling the distribution and reorganization of Earth materials through erosion and sediment transport. This study will test how the Earth’s crust deforms into mountains in the middle of tectonic plates rather than at the edges. The PIs will use thermochronology (the study of mineral cooling histories) to measure the timing of mountain development and conduct field-based studies of sedimentary rocks to study changes in erosion and deposition patterns caused by mountain uplift. These results will be compared to numerical models testing different ways to form mountains in the middle of tectonic plates. This research will provide important societal outcomes by 1) supporting the training of graduate and undergraduate students in STEM fields including minority and underrepresented students at a Hispanic Serving Institution, 2) increasing participation of women in STEM as both Principal Investigators and graduate students within this project, 3) increasing public scientific literacy through undergraduate education and education outreach, 4) developing partnerships between American and Mongolian scientists, and 5) the development of online interactive field tours for undergraduate education. Recent large-scale, interdisciplinary projects have led to major advances in our understanding of the rates, relative timing, and periodicity of tectonic plate margin processes that define orographic landscapes. However, our understanding of plate interior orogenesis is less evolved, as intracontinental orogens defy models of orogenesis as a plate-boundary driven process. The Mongolian Altai are part of one of the largest intracontinental orogenic systems–the Central Asian Orogenic Belt, and yet limited data exist to explain the origin of this mountain system. This project will test specific models of intracontinental orogenesis in the Mongolia Altai, each of which predict a different timing, rate, and style of uplift. This research will integrate bedrock and detrital thermochronology, sedimentology and basin analysis, and geomechanical modeling to document the timing of onset of intracontinental orogenesis in the Mongolian Altai; understand fundamental (rheological, geodynamic, inherited) controls on the formation of an orographic landscape in this region; and to understand the possible conditions that produce intracontinental deformation from plate boundary forces and the timescales on which this deformation occurs. These outcomes will allow testing of whether the Mongolian Altai are relict topography from a Mesozoic suture zone, are a geodynamic feature of isostatic or dynamic processes, or formed due to localized deformation from Cenozoic plate boundary stresses. Field and analytical data will provide direct observations to test these hypotheses that can be further constrained by numerical models that interrogate the geomechanical plausibility of these processes. This study will not only provide the first basement thermochronologic dataset from a ~800 km along strike zone within the Mongolian Altai and the first detrital thermochronologic dataset from the entire Altai system (2000 km strike length), but will integrate this dataset with work in contemporaneous sedimentary basins and geomechanical modeling to put these data in a well-constrained geologic context. The proposed research will also improve our understanding of what processes drive formation of intracontinental orogens globally, a major outstanding question in the field of tectonics.This project is jointly funded by the Tectonics program in the division of Earth Sciences and the Established Program to Stimulate Competitive Research (EPSCoR).This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

蒙古阿尔泰山是蒙古西部一条长约 2000 公里的山脉，是中亚广阔山区（称为中亚造山带）的一部分。了解距现代板块 1000 公里的山脉系统。最初形成的边界非常重要，因为阿尔泰山脉在调节亚洲气候和生物多样性以及通过侵蚀和沉积物运输控制地球物质的分布和重组方面发挥着重要作用。在构造板块的中部而不是边缘变形为山脉 PI 将使用热年代学（矿物冷却历史的研究）来测量山脉发展的时间，并对沉积岩进行实地研究，以研究侵蚀和侵蚀的变化。这些结果将与测试构造板块中部形成山脉的不同方式的数值模型进行比较，这项研究将通过以下方式提供重要的社会成果：1）支持研究生和本科生在 STEM 领域的培训，包括。少数民族和西班牙裔服务机构中学生比例不足，2）增加女性作为该项目首席研究员和研究生参与 STEM，3）通过本科教育和教育推广提高公众科学素养，4）美国和蒙古科学家之间发展伙伴关系， 5）本科教育在线互动实地考察的发展使我们对定义地形地貌的构造板块边缘过程的速率、相对时间和周期性的理解取得了重大进展。然而，我们对板块内部造山作用的理解还不够成熟，因为陆内造山带不符合板块边界驱动过程的造山作用模型，蒙古阿尔泰山是最大的陆内造山系统之一——中亚造山带的一部分，但仍然有限。该项目将测试蒙古阿尔泰地区陆内造山作用的具体模型，每个模型都预测不同的时间、速率和类型。这项研究将整合基岩和碎屑热年代学、沉积学和盆地分析以及地质力学建模，以记录蒙古阿尔泰地区陆内造山作用发生的时间；了解对地形景观形成的基本（流变、地球动力学、继承）控制。在该区域；并了解板块边界力产生陆内变形的可能条件以及发生这种变形的时间尺度。蒙古阿尔泰山是中生代缝合带的遗迹地形，是均衡或动态过程的地球动力学特征，或者是由于新生代板块边界应力的局部变形而形成的。现场和分析数据将为检验这些可以进一步约束的假设提供直接观察。通过质疑这些过程的地质力学合理性的数值模型，这项研究不仅将提供蒙古走向带约 800 公里的第一个基底热年代学数据集。阿尔泰和整个阿尔泰系统（走向长度 2000 公里）的第一个碎屑热年代学数据集，但还将将该数据集与同期沉积盆地和地质力学建模工作相结合，以将这些数据置于严格约束的地质背景中。提高我们对全球陆内造山带形成过程的理解，这是构造学领域的一个重大悬而未决的问题。该项目由构造学计划联合资助该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。