Collaborative Research: Punctuated versus gradual topographic evolution of Cordilleran-style orogenic belts

合作研究：科迪勒拉式造山带的间断与渐进地形演化

• 批准号: 1650313
• 负责人: Mark Brandon
• 金额: $ 18.19万
• 依托单位: Yale University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-02-01 至 2023-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1650313&HistoricalAwards=false
• 关键词: Collaborative; Research; Punctuated; versus; gradual

Researchers have long debated how large Cordilleran orogens such as the Sierra Nevada, Cascades and Patagonian Andes develop through time. In particular, two dominant theories have emerged that explain how mountain belts evolve in response to subduction of oceanic crust beneath continental crust. These theories argue for either protracted mountain building, or an episodic model in which topography repeatedly rises and falls due to crustal shortening and removal of lithosphere beneath a subducting arc. The southern Patagonian Andes provides a natural laboratory for evaluating the drivers of long-term topographic change in a classic Cordilleran Orogen. This study aims to quantify the elevation history of the Southern Patagonia Andes for the last 100 million years to test these competing theories for Cordilleran mountain building. Results will improve understanding about how subduction processes shape the Earth's surface and will have broad implications for understanding current and past seismic activity, hazards, and resources. In addition, insight into changes in the ancient environment will shed light on how evolution of large mountain belts influences plants and animals over millions of years. A new Augmented Reality exhibit at the Yale University Peabody Museum will enable countless visitors to virtually explore how mountains influence precipitation and illustrate important concepts in atmospheric processes and geomorphology. Other important societal outcomes include providing support for an early career faculty researcher and broadening participation in an important STEM discipline through graduate and undergraduate recruiting.There has been a long debate about punctuated versus steady orogeny. In particular, two opposing ideas argue for either protracted orogenesis or an episodic "Cordilleran cycle" in which topography repeatedly rises and falls due to crustal shortening and convective removal of sub-arc lithosphere. The large Cordilleran orogens (e.g. Sierra Nevada, Cascades, Southern Andes) all host massive granitic batholiths that formed from the partial melting of the sub-arc mantle and the migration of silicic melts through the upper crust. This project explores the idea that emplacement of granitic batholiths was the primary driver of topography in the Patagonian Andes and other Cordilleran orogens. The proposed work will reconstruct the Cretaceous to recent stable isotopic composition of paleoprecipitation on the windward and leeward side of the Patagonian Andes to test competing hypotheses for the formation of Cordilleran-style orogens. Volcanic glasses, soil carbonates and sedimentary leaf waxes from several well-dated Cretaceous to recent sedimentary basins will be sampled to reconstruct precipitation deltaD and delta18O. Isotope data will be coupled with a numerical atmospheric physics model with high-resolution water isotope fields to constrain the timing and spatial heterogeneity of topographic change in the Patagonian Andes. The isotope-enabled numerical model deals with observed complexities in the behavior of airflow and produces realistic representation of modern distribution of precipitation isotopes on the scale of an orogen. This approach enables separation of climatic and topographic effects on precipitation isotopes and more accurate reconstructions of topographic change.

长期以来，研究人员一直在争论内华达州山脉、喀斯喀特山脉和巴塔哥尼亚安第斯山脉等大型科迪勒拉造山带是如何随着时间的推移而发展的。特别是，出现了两种占主导地位的理论，解释了山脉带如何演变，以应对大陆地壳下的洋壳俯冲。这些理论认为，要么是长期的造山运动，要么是一个幕式的模型，其中地形反复上升和福尔斯下降，由于地壳缩短和岩石圈下的俯冲弧。巴塔哥尼亚南部的安第斯山脉提供了一个天然的实验室，以评估在一个典型的科迪勒拉造山带长期地形变化的驱动因素。这项研究的目的是量化南巴塔哥尼亚安第斯山脉在过去1亿年的海拔历史，以测试这些相互竞争的理论，为科迪尔山脉建设。研究结果将提高对俯冲过程如何塑造地球表面的理解，并将对理解当前和过去的地震活动、灾害和资源产生广泛的影响。此外，对古代环境变化的深入了解将揭示大型山脉带的演变如何影响数百万年来的植物和动物。耶鲁大学皮博迪博物馆的一个新的增强现实展览将使无数游客能够虚拟地探索山脉如何影响降水，并说明大气过程和地貌学中的重要概念。其他重要的社会成果包括为早期职业教师研究人员提供支持，并通过研究生和本科生招聘扩大对重要STEM学科的参与。特别是，两个对立的观点认为，无论是长期的造山作用或幕式的“科迪勒拉旋回”，地形反复上升和福尔斯下降，由于地壳缩短和对流去除弧下岩石圈。大型的科迪勒拉造山带（如内华达州山脉、喀斯喀特山脉、南安第斯山脉）都有块状花岗岩岩基，这些岩基是由弧下地幔的部分熔融和地幔熔融物通过上地壳的迁移形成的。该项目探讨了花岗岩岩基的侵位是巴塔哥尼亚安第斯山脉和其他科迪尔山脉地形的主要驱动力的想法。拟议的工作将重建白垩纪到最近的稳定同位素组成的古沉淀物的迎风和背风侧的巴塔哥尼亚安第斯山脉，以测试竞争的假设形成的科迪勒拉式造山带。从几个白垩纪到现代沉积盆地的火山玻璃、土壤碳酸盐和沉积叶蜡将被取样，以重建降水三角洲D和三角洲18 O。同位素数据将与具有高分辨率水同位素场的数值大气物理模型相结合，以限制巴塔哥尼亚安第斯山脉地形变化的时间和空间异质性。同位素启用的数值模型处理所观察到的复杂性的行为的气流，并产生现实的代表性的现代分布的降水同位素的规模的造山带。这种方法可以分离气候和地形对降水同位素的影响，并更准确地重建地形变化。

项目成果

Transient glacial incision in the Patagonian Andes from ~6 Ma to present

巴塔哥尼亚安第斯山脉从约 6 Ma 到现在的短暂冰川切割

• DOI: 10.1126/sciadv.aay1641
• 发表时间: 2020
• 期刊: Science Advances
• 影响因子: 13.6
• 作者: Willett, C. D.;Ma, K. F.;Brandon, M. T.;Hourigan, J. K.;Christeleit, E. C.;Shuster, D. L.
• 通讯作者: Shuster, D. L.

Growth and steady state of the Patagonian Andes

巴塔哥尼亚安第斯山脉的生长和稳定状态

• DOI: 10.2475/06.2019.01
• 发表时间: 2019
• 期刊: American Journal of Science
• 影响因子: 2.9
• 作者: Colwyn, David Auerbach;Brandon, Mark T.;Hren, Michael T.;Hourigan, Jeremy;Pacini, Astrid;Cosgrove, Martha G.;Midzik, Maya;Garreaud, René D.;Metzger, Christine
• 通讯作者: Metzger, Christine

On backflow associated with oceanic and continental subduction

与海洋和大陆俯冲相关的回流

• DOI: 10.1093/gji/ggab246
• 发表时间: 2021
• 期刊: Geophysical Journal International
• 影响因子: 2.8
• 作者: Moulas, Evangelos;Brandon, Mark T;Vaughan Hammon, Joshua D;Schmalholz, Stefan M
• 通讯作者: Schmalholz, Stefan M