Collaborative Research: Effect of Contrasting Structural and Compositional Inheritances on the Development of Rifting Margins

合作研究：对比结构和成分继承对裂谷边缘发展的影响

• 批准号: 1753555
• 负责人: Luc Lavier
• 金额: $ 4.1万
• 依托单位: University of Texas at Austin
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-06-01 至 2020-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1753555&HistoricalAwards=false
• 关键词: Collaborative; Research; Effect; Contrasting; Structural

Throughout Earth's history continents have broken apart and reassembled as part of the fundamental plate tectonic evolution of the planet. How continents break apart by rifting processes is thought to be predefined by inherent structural and compositional variability of Earth's crust and mantle that make up the lithosphere and is likely inherited from previous tectonic events. Understanding the style of continental breakup provides fundamental information for the exploration for energy and mineral resources and to understanding the geologic hazards associated with these processes. Geological observations often support the fact that these inheritances are key parameters in the development of rift structures but the extent to which these inheritances play a role during the rifting process remain unclear. This project investigates how the variable composition of continental lithosphere and the presence of inherited geological structures affect rifting processes. A multi-disciplinary approach will employ geological and geophysical observations to characterize inheritances in the crust and mantle of the lithosphere. These observations will be integrated into numerical models that simulate the deformation of the lithosphere over millions of years by extension. The results of this project will fundamentally advance the understanding of lithospheric scale deformation processes and impact structural geology, computational geosciences and potentially the fossil fuel communities. Under broader impacts the project supports an early career female researcher at Texas State University, a primarily Hispanic-serving institution, and a master student will be recruited to participate directly in the research.Passive margins define about half of the Earth's coastlines and have been the focus of numerous studies in recent decades. While understanding of rifting processes has greatly improved, fundamental questions remain on the effects of inherited conditions on localization processes in extending lithosphere. Multiple studies suggest that structural, compositional and thermal inheritances are key parameters in the development of rift structures. However, the extent to which they play a role during breakup is still unclear. This project will address the hypothesis that inheritances strongly affect rifting processes and can explain: 1) the distribution of strain during the initial phase of deformation, 2) the mechanism of thinning during the rifting process, and 3) the mechanism leading to the exhumation and/or the formation of oceanic crust. To test this hypothesis numerical rifting experiments will be run with both structural and compositional inheritances. Inheritances are parameterized as oriented fabrics obtained from 2D seismic and 3D structural observations. A polymineralic composition is assigned to these heterogeneities in order to account for the natural variation in compositions observed in the continental lithosphere. In order to constrain the models, a multidisciplinary approach will be used that combines: 1) the analysis of geological and geophysical data, 2) a systematic exploration of the effects of numerical modeling experiments using a bimineralic rheology, and 3) a case study of the Northeastern Canadian margin with 2D and 3D numerical models. This approach will allow for a large amount of quantitative information on rift evolution to be acquired by independently varying the composition, distribution and orientation of inheritances. Results will help improve understanding of strain distribution, localization processes and mechanisms of deformation during continental breakup, and visualize the dynamic evolution of rifting processes depending on the type of inheritances.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.

在整个地球历史上，由于地球的基本板块构造演变的一部分而破裂并重新组装。 人们认为，如何通过裂缝过程破裂，被认为是由构成岩石圈的地壳和地幔的固有结构和组成变异所预期的，并且很可能是从以前的构造事件中遗传而来的。了解大陆分手的风格为能源和矿产资源的探索提供了基本信息，并了解与这些过程相关的地质危害。地质观察通常支持这样一个事实，即这些继承是裂谷结构发展的关键参数，但是这些继承在裂谷过程中起作用的程度尚不清楚。该项目研究了大陆岩石圈的可变组成以及遗传地质结构的存在如何影响裂谷过程。多学科的方法将采用地质和地球物理观测来表征岩石圈地壳和地幔中的遗传。这些观察结果将集成到数值模型中，这些模型将在数百万年内延长地模拟岩石圈的变形。 该项目的结果将从根本上提高对岩石圈尺度变形过程的理解，并影响结构地质，计算地球科学以及潜在的化石燃料群落。在更广泛的影响下，该项目支持德克萨斯州立大学的一名早期职业女性研究员，这是一家主要是西班牙裔服务机构，将招募一名硕士学生直接参与研究。Passive-ragive-ragive-ragive rains定义了大约一半的地球海岸线，并且是近几十年来许多研究的重点。虽然对裂谷过程的理解大大提高，但基本问题仍然是遗传条件对扩展岩石圈的定位过程的影响。多项研究表明，结构，组成和热遗传是裂谷结构发展的关键参数。但是，他们在分手期间发挥作用的程度尚不清楚。该项目将解决以下假设，即继承强烈影响裂谷过程，并可以解释：1）在变形的初始阶段，应变分布，2）在裂谷过程中变薄的机制，以及3）导致海洋壳的挖掘和/或形成的机制。为了检验该假设的数值裂谷实验，将使用结构和组成遗传进行运行。遗传被参​​数化为从2D地震和3D结构观测中获得的定向织物。为了解释大陆岩石圈中观察到的组成的自然变化，将多种矿物组成分配给这些异质性。为了限制模型，将使用一种结合的多学科方法：1）地质和地球物理数据的分析，2）对使用双层流性的数值建模实验的影响的系统探索，以及3）对2D和3D数字模型的东北加拿大范围的案例研究。这种方法将允许通过独立改变继承的组成，分布和方向来获取有关裂谷进化的大量定量信息。结果将有助于提高大陆分解过程中的应变分布，定位过程和变形机制的理解，并根据继承类型可视化裂变过程的动态演变。该奖项反映了NSF的法定任务，并认为通过基金会的知识和更广泛的影响，可以通过评估通过评估来进行支持。