Collaborative Research: Internal and external drivers of orogenic episodicity in the Ecuadorian Andes

合作研究：厄瓜多尔安第斯山脉造山偶发性的内部和外部驱动因素

• 批准号: 1946662
• 负责人: James Chapman
• 金额: $ 23.67万
• 依托单位: University of Wyoming
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-05-01 至 2022-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1946662&HistoricalAwards=false
• 关键词: Collaborative; Research; Internal; external; drivers

Ecuador contains an important record of subduction-related magmatism and tectonic environments during the building of the Andes Mountains. This research will address the roles of tectonic cycles and the accretion of oceanic crust in regulating episodes of magmatism, crustal thickening, and basin subsidence along ocean-continent subduction margins. The project will integrate results from a regional traverse across several sedimentary basins with the record of magmatism across Ecuador, the narrowest segment of the Andes. A range of analytical techniques will be employed to determine the timing of major shifts in basin development, sediment sources, and past drainages, and to recognize periods of crustal thickening, changes in sources of magmatism, and the influence of accreted oceanic crust. The study will provide insights into the geologic processes and geohazards along ocean-continent subduction plate boundaries, offering information that will benefit society by improving risk assessment and infrastructure planning. The project will also catalyze new academic collaborations within the framework of international learning experiences that will facilitate longer term collaborations between US and Ecuadorian researchers, including development of shared undergraduate and graduate geoscience field-course and field-trip opportunities.Over the past decade, competing perspectives have emerged on the tectonic evolution of Cordilleran ocean-continent plate boundaries, including the geologic history of the Andes, the global archetype for Cordilleran convergent systems. Debate largely originates from contrasting emphases on different regions (forearc vs. retroarc) and different components (basins vs. magmatic arc vs. fold-thrust belt) of Cordilleran systems. This project will incorporate analytical techniques, such as sedimentary basin analysis, isotope geochemistry, petrology, and U-Pb geochronology, to identify potentially coupled episodic phases of basin evolution and arc magmatism that may be linked to internally driven orogenic processes (including underthrusting, high-flux magmatism, and buildup then foundering of crustal/lithospheric roots), or externally driven tectonic processes including fluctuating slab dynamics (cycles of subduction shallowing vs. steepening and associated rapid vs. diminished shortening and subsidence) and oceanic terrane accretion. Ecuador contains an important yet underappreciated record of tectonic quiescence or possible extension during what has been long regarded as uninterrupted Cenozoic shortening, thickening, and uplift along the entire Andean margin. Such a fluctuating pattern of mountain building may govern the structural and stratigraphic evolution of many ocean-continent convergent margins, with implications for the tectonic regimes of subduction and collisional systems.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.

厄瓜多尔拥有安第斯山脉形成过程中与俯冲相关的岩浆作用和构造环境的重要记录。 这项研究将探讨构造旋回和洋壳增生在调节岩浆活动、地壳增厚和沿洋-大陆俯冲边缘的盆地沉降中的作用。 该项目将整合跨多个沉积盆地的区域穿越结果和厄瓜多尔（安第斯山脉最狭窄部分）的岩浆活动记录。 将采用一系列分析技术来确定盆地发展、沉积物来源和过去排水系统重大变化的时间，并识别地壳增厚时期、岩浆来源的变化以及增生洋壳的影响。 该研究将深入了解海洋-大陆俯冲板块边界的地质过程和地质灾害，提供通过改进风险评估和基础设施规划造福社会的信息。 该项目还将促进国际学习经验框架内的新学术合作，从而促进美国和厄瓜多尔研究人员之间的长期合作，包括开发共享的本科生和研究生地球科学实地课程和实地考察机会。在过去的十年中，竞争关于科迪勒拉洋-大陆板块边界的构造演化的观点已经出现，包括安第斯山脉的地质历史，这是科迪勒拉聚合系统的全球原型。 争论主要源于对科迪勒拉系统不同区域（弧前与弧后）和不同组成部分（盆地、岩浆弧与褶皱逆冲带）的不同侧重点。 该项目将结合沉积盆地分析、同位素地球化学、岩石学和 U-Pb 地质年代学等分析技术，以确定盆地演化和弧岩浆作用的潜在耦合阶段，这些阶段可能与内部驱动的造山过程（包括逆冲、高-通量岩浆作用，以及地壳/岩石圈根部的堆积和沉没），或外部驱动的构造过程，包括波动板片动力学（俯冲变浅的循环）与陡峭和相关的快速与减少的缩短和沉降）和海洋地体增生。 厄瓜多尔拥有一个重要但未被充分认识的构造静止或可能的伸展记录，长期以来一直被认为是沿着整个安第斯山脉边缘不间断的新生代缩短、增厚和隆起。 这种波动的造山模式可能控制着许多海洋-大陆汇聚边缘的结构和地层演化，并对俯冲和碰撞系统的构造机制产生影响。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。

项目成果

The causes of continental arc flare ups and drivers of episodic magmatic activity in Cordilleran orogenic systems

科迪勒拉造山系统大陆弧爆发的原因和间歇性岩浆活动的驱动因素

• DOI: 10.1016/j.lithos.2021.106307
• 发表时间: 2021-10-01
• 期刊: Lithos
• 影响因子: 3.5
• 作者: J. Chapman;J. Shields;M. Ducea;S. Paterson;Snir Attia;K. Ardill
• 通讯作者: K. Ardill