Collaborative Research: Evaluating the role of terrane accretion on the evolution of indenter corner fault systems, an example from the eastern Himalaya

合作研究：评估地体增生对压头角断层系统演化的作用，以喜马拉雅东部为例

• 批准号: 2319476
• 负责人: Karl Lang
• 金额: $ 23万
• 依托单位: Georgia Tech Research Corporation
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-08-01 至 2026-07-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2319476&HistoricalAwards=false
• 关键词: Collaborative; Research; Evaluating; role; terrane

The collision of continental tectonic plates produces some of the highest topography, deepest sedimentary basins, and highest potential for large earthquakes on Earth. To explain how these unique plate boundaries evolve, geologists commonly simulate a collision between a rigid tectonic plate that collides with and indents a weaker tectonic plate. Recent observations from the eastern Himalaya and Alaska instead suggest that indenting plates in nature are not entirely rigid, particularly when they contain pieces of crustal blocks accreted from prior collisions in the geologic past. This implies that active fault systems may also deform (and generate earthquakes) within the indenting plate as well as the indented plate, changing the way geoscientists understand plate boundary faults within continental collision zones. This project will study the complex tectonic setting of the eastern Himalaya, a natural laboratory for testing the hypothesis that prior accreted terranes fundamentally change the active fault systems at the margins of a collision zone. This research will address three Grand Challenges outlined in a 2018 NSF Community Vision Document for Tectonics research and will strengthen international ties between US scientists and researchers at multiple Indian universities and research centers, as well as a local non-governmental organization promoting public scientific literacy. This project will further facilitate knowledge transfer between US and international partners by conducting a formal interlaboratory comparison of analytical methods, co-organizing two workshops for US and Indian undergraduate students, and developing K-12 educational outreach. This project will also support two early career faculty and promote the full participation of two graduate and two undergraduate students who will be recruited through programs designed to broaden participation of traditionally underrepresented groups in the geosciences.Orogenic syntaxes are regions of high crustal strain that accommodate the transition from convergence to strike-slip motion at the margins of an indenting plate collision. For several decades, Tectonics research has focused on strain partitioning within the indented plate of a collision zone, this focus has neglected the important influence of strain partitioning within the indenting plate, and in particular, the role of sliver terrane accretion on the evolution of indenter corner fault intersections. Observations from both the eastern Himalayan and Alaskan orogens suggest that the accretion of sliver terranes along transform faults flanking collision zones can lead to a ‘double collision’ where a once-stable fault intersection changes into an unstable triple junction, altering the kinematics of indenter corner fault systems and the pattern of upper plate deformation. To evaluate the broader influence of terrane accretion on collisional orogenesis, this 3-year project will reconstruct the kinematic history of a triple junction in the eastern Himalayan indenter corner. This project focuses on the kinematic history of the Noa Dihing Fault, a key structure at the center of the eastern Himalaya indenter corner that juxtaposes the Indian-Eurasian collision zone with the subduction zone between Indian and the Burma Terrane, as well as the Burma-Eurasia transform zone. This project will constrain the late Cenozoic kinematic history of the Noa Dihing Fault through a combination of field mapping, zircon U-Pb geochronology, fault kinematic analysis, and thermo-kinematic modeling of apatite fission-track, zircon fission track and 40Ar/40Ar thermochronology in the Noa Dihing Fault hanging wall. Testing this hypothesis that sliver terranes concentrate strain within continental indenter corners will help to explain differences in structural style between indenter corners in the same tectonic setting (e.g. differences in the curvature between the eastern and western Himalayan indenter corners) and also relate similarities between indenter corners in different tectonic settings (e.g. southern Alaska and the eastern Himalaya). This is a new way of thinking about indenter tectonics and could provide a complementary perspective that builds further helps to link research in Alaskan and Himalayan orogens.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.

连续的构造板的碰撞产生了一些最高的地形，最深的沉积低音和地球大地震的最高潜力。为了解释这些独特的板块边界如何发展，地质学家通常会模拟与较弱的构造板碰撞并凹陷的刚性构造板之间的碰撞。相反，来自喜马拉雅东部和阿拉斯加东部的最新观察表明，自然界中的缩进板并非完全僵化，尤其是当它们包含从地质过去碰撞中接受的地壳块时。这意味着主动断层系统还可能在缩进板和凹陷板中变形（并生成地震），从而改变地球科学家了解连续碰撞区域内的板边界断层的方式。该项目将研究喜马拉雅东部的复杂构造环境，这是一个自然实验室，用于检验以下假设，即先前招募的地形从根本上改变了碰撞区域边缘的主动断层系统。这项研究将解决2018年NSF社区愿景文档的三个宏伟挑战，并将加强印度大学和研究中心的美国科学家与研究人员之间的国际联系，以及促进公共科学素养的当地非政府组织。该项目将通过对分析方法进行正式的实验室进行比较，为美国和印度本科生共同组织，并开发K-12教育外展，进一步支持美国与国际合作伙伴之间的知识转移。该项目还将支持两位早期职业教师，并促进两位研究生和两个本科生的全面参与，这些学生将通过旨在扩大传统上代表性不足的群体的计划来招募，而构成语法是高地壳菌株的区域，这些区域是高层菌株，这些区域接受从融合到撞击板的转换运动的过渡到拼凑而成的型号的菌株。数十年来，构造研究一直集中在碰撞区域内的压缩板上的应变分配，该重点忽略了缩进板中应变分配的重要影响，尤其是sliver地层积聚对凹痕角断层交叉口进化的作用。来自东部喜马拉雅山脉和阿拉斯加牛根的观察表明，沿侧面碰撞区域的断层沿变换的底层吸收会导致“双重碰撞”，在这种情况下，曾经稳定的断层交点会变成不稳定的三重连接，从而改变了凹痕拐角断层系统和上层板置型的动力学。为了评估地形积聚对碰撞的更广泛影响，这个为期三年的项目将重建在喜马拉雅东部契约角三连接的运动学历史。该项目着重于Noa Dihing断层的运动学历史，这是位于喜马拉雅东部契约角中心的关键结构，将印度 - 欧拉西亚碰撞区与印度和缅甸地形之间的俯冲区以及缅甸 - 欧拉西亚变换区并列。 This project will constrain the late Cenozoic kinematic history of the Noa Dihing Fault through a combination of field mapping, zircon U-Pb geochronology, fault kinematic analysis, and thermo-kinematic modeling of apatite fission-track, zircon fission track and 40Ar/40Ar thermochronology in the Noa Dihing Fault hanging wall.测试这一假设，即连续的纵向弯曲弯道内的滑块地形浓度应变将有助于解释同一构造环境中的斜角之间的结构风格差异（例如，东喜马拉雅山脉不可分割的近距离界面之间的曲率差异），以及在不同的tectoronic setertings和Southers Alaska和Southers Alaska的Indventur Corners之间的相关性相似（也是如此）。这是一种思考Indventur Tectonics的新方法，可以提供一个完整的观点，可以进一步建立，有助于将阿拉斯加和喜马拉雅绿色的研究联系起来。该奖项反映了NSF的法定任务，并被认为是值得通过基金会的知识分子优点和更广泛影响的审查标准来通过评估来获得支持的。