Collaborative Research: Lithospheric Structure and Evolution of the Rocky Mountains - beginning Phase 2 Geodynamic Processes

合作研究：落基山脉的岩石圈结构和演化——第二阶段地球动力学过程的开始

• 批准号: 0003577
• 负责人: Roy Johnson
• 金额: $ 4.5万
• 依托单位: University of Arizona
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-05-01 至 2002-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0003577&HistoricalAwards=false
• 关键词: Collaborative; Research; Lithospheric; Structure; Evolution

0003577JohnsonThe western U.S. is one of the best places in the world to study continental evolution because there is a preserved unique record of the growth, stabilization, maturation, rifting, and incipient dismemberment of a continent. In particular, we can see how older lithospheric structures (in this case Archean and Proterozoic) influenced younger tectonic events, including development of the huge, presently active, orogenic plateau that dominates the western U.S. and the progressive dismemberment and dispersal of continental fragments along its active western margin. Continents are the long-term record keepers of plate interactions before 200 Ma. However, accumulated modification often obscures the previous record. The western U.S. is unique in that this part of the continent was assembled in the Proterozoic around an Archean "cratonic core", then was truncated in the Phanerozoic at a high angle so as to create a new continental margin oblique to the Precambrian structures. The result was the creation of a wide region - the western U.S. - where nature "caught" all stages of structural reactivation and continental modification.The main goal of the CD-ROM (Continental Dynamics of the Rocky Mountains) Project is to understand the processes of formation and modification of continental lithosphere. Phase 1 of the CD-ROM experiment was a three year project to improve our structural and petrologic knowledge of the lithosphere and to test the hypothesis that the lithospheric structure produced during assembly of southwestern North America has profoundly influenced physical and chemical modification of the continental lithosphere during all subsequent magmatic and tectonic events, including those related to the ongoing asthenospheric flow. The principal investigators studied two Proterozoic structures with a range of seismic and geologic methods: the Cheyenne Belt and the Jemez lineament. Reflection, refraction, and teleseismic investigations are providing crustal - and lithospheric - scale images of major structures. A more complete picture of the evolution of the lithosphere has been added by geologic studies of Precambrian shear zones and Phanerozoic structures, xenolith studies, and geomorphologic and exhumation studies of present landforms. Phase 1 brought together 18 investigators from 14 institutions, including collaboration with a German-funded refraction team. With these awards, one year of funding is provided to continue to process, interpret, and integrate the diverse data sets generated in Phase 1 and to begin developing geodynamic models. The Principal Investigators will also explore new methods of data integration towards the goal of developing a "master model" for lithospheric structure.***

0003577约翰逊美国西部是世界上研究大陆演化最好的地方之一，因为那里保存着大陆生长、稳定、成熟、裂谷和早期肢解的独特记录。 特别是，我们可以看到更古老的岩石圈结构（这里指的是太古代和元古代）是如何影响更年轻的构造事件的，包括占据美国西部的巨大的、目前活跃的造山高原的发展，以及大陆碎片沿着沿着活跃的西部边缘的逐渐肢解和分散。 大陆是200 Ma以前板块相互作用的长期记录者。 然而，累积的修改往往掩盖了以前的记录。 美国西部的独特之处在于，该大陆的这一部分在元古代围绕着太古代的“寒武纪核”聚集，然后在元古界以高角度被截断，从而形成一个新的大陆边缘，倾斜于前寒武纪构造。 其结果是创造了一个广阔的地区-美国西部-自然“抓住”所有阶段的结构复活和大陆修改。光盘（落基山脉大陆动力学）项目的主要目标是了解大陆岩石圈的形成和修改的过程。 光盘实验的第一阶段是一个为期三年的项目，以提高我们的岩石圈的结构和岩石学知识，并测试的假设，即岩石圈结构在组装过程中产生的北美西南部已深刻地影响物理和化学修改大陆岩石圈在所有随后的岩浆和构造事件，包括那些有关正在进行的软流圈流。 主要研究人员用一系列地震和地质方法研究了两个元古代构造：夏延带和杰梅斯线性构造。 反射、折射和折射率的研究提供了主要结构的地壳和岩石圈尺度的图像。 通过对前寒武纪剪切带和古生代构造的地质研究、捕虏体研究以及对现今地貌的地貌学和剥露研究，增加了对岩石圈演化的更完整的认识。 第一阶段汇集了来自14个机构的18名研究人员，包括与德国资助的屈光小组合作。 通过这些奖项，提供了一年的资金，以继续处理，解释和整合第一阶段产生的各种数据集，并开始开发地球动力学模型。 主要研究人员还将探索数据整合的新方法，以实现开发岩石圈结构“主模型”的目标。