Collaborative Research: Lithospheric Structure andEvolution of the Rocky Mountain Transect of the Western U.S.: An Integrated Geological and Geophysical Investigation

合作研究：美国西部落基山脉横断面的岩石圈结构和演化：综合地质和地球物理调查

• 批准号: 9614208
• 负责人: Roy Johnson
• 金额: $ 10.93万
• 依托单位: University of Arizona
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-12-15 至 2000-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9614208&HistoricalAwards=false
• 关键词: Collaborative; Research; Lithospheric; Structure; andEvolution

9614208 Johnson This collaborative study is aimed at understanding the evolution of the lithosphere of the Rocky Mountain transect in the North American southwest. This transect is located at the juncture of two globally-unique tectonic regimes, each of fundamental importance for understanding continental tectonics and together representing an outstanding field laboratory for studies of continental lithosphere. First, a 1000 km wide juvenile Proterozoic orogenic belt records rapid accretion of continental materials from mantle sources and their assembly to southern Laurentia along NE-trending boundaries between 1.8 and 1.6 Ga. Second, the present high elevation of the SW in general and the Rocky Mountains in particular is the manifestation of Laramide, Tertiary, and still ongoing modification of Proterozoic Lithosphere that has resulted in a wide NW-trending mantle boundary zone between old, cold, high velocity mantle in the continental interior and hotter, lower velocity mantle in the western U.S. By examining the present-day lithospheric structure across ancient boundaries, the P.I.s hope to better understand the interplay between "active" and "passive" processes during lithospheric evolution. Their principal hypothesis is that lithospheric structures produced during assembly of the southwestern U.S. have profoundly influenced physical and chemical modification of the continental lithosphere during all subsequent magmatic and tectonic events, including those related to the ongoing reorganization of small-scale asthenospheric convection and replacement of lithosphere by asthenosphere. To test this hypothesis, they propose an integrated set of multi-scale experiments using state of the art geophysical, geological and geochemical techniques that, together, are designed to decipher lithosphere structure and evolution, and processes of lithosphere formation and deformation. ***

9614208约翰逊 这项合作研究的目的是了解北美西南部落基山脉样带岩石圈的演变。 该断面位于两个全球独特的构造体系的交界处，每个体系对于理解大陆构造都具有根本的重要性，并且共同代表了大陆岩石圈研究的杰出现场实验室。 首先，1000 km宽的幼年元古代造山带记录了1.8 - 1.6 Ga期间来自地幔源的大陆物质的快速增生，并沿沿着NE向边界向南劳伦提斯聚集。 第二，目前西南部的高海拔，特别是落基山脉，是Laramide，第三纪和仍在进行的元古代岩石圈改造的表现，这导致了大陆内部古老，寒冷，高速地幔和较热，通过研究跨越古代边界的现今岩石圈结构，PI希望更好地理解岩石圈演化过程中“主动”和“被动”过程之间的相互作用。 他们的主要假设是，在美国西南部的组装过程中产生的岩石圈结构深刻地影响了所有随后的岩浆和构造事件中大陆岩石圈的物理和化学修改，包括那些与小规模软流圈对流和软流圈替换岩石圈有关的正在进行的重组。 为了验证这一假设，他们提出了一套综合的多尺度实验，使用最先进的地球物理，地质和地球化学技术，旨在破译岩石圈结构和演化，以及岩石圈形成和变形的过程。 ***