Testing a New Model of the Tertiary Evolution of the Colorado Plateau Based on Constraints from Magmatic Patterns, Xenoliths, Geologic, and Geophysical Data

基于岩浆模式、捕虏体、地质和地球物理数据的约束，测试科罗拉多高原第三次演化的新模型

• 批准号: 0538022
• 负责人: Mousumi Roy
• 金额: $ 10万
• 依托单位: University of New Mexico
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-01-01 至 2008-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0538022&HistoricalAwards=false
• 关键词: Testing; New; Model; Tertiary; Evolution

This project integrates available data on the tectonic and physiographic evolution of the Colorado Plateau to test a geodynamic model for the Tertiary history of this region. The centerpiece of this model is the idea that the Colorado Plateau is underlain by compositionally distinct mantle lithosphere that is depleted in basaltic components. In this scenario, intrinsic chemical buoyancy of the lithosphere may explain the enigmatic tectonic coherence and stability of the Colorado Plateau. The geodynamic implications of this idea are being explored by comparing numerical model results constraints derived from many diverse datasets, including: Tertiary magmatic patterns, heat flow, seismic velocity variations, xenoliths, rock exhumation, and rock and surface uplift. This research includes explicit consideration of possibly differing tectonic histories of the edges vs. the middle of the Colorado Plateau. The primary goal of this project is to shed light on two of the most puzzling aspects of the Tertiary evolution of the Colorado Plateau - the timing and mechanism of its rock and surface uplift and its relative tectonic stability during a time when vigorous magmatism and active deformation affected the rest of the western United States. The mechanism and timing of the uplift of the Colorado Plateau is a long-standing puzzle that has challenged some of the best geologists, including J.W. Powell, C. Dutton, and G.K. Gilbert. This project develops a new idea for the history of the region, namely that the uplift of the Colorado Plateau is intimately related to the chemical structure of the North American plate and is governed by intense heating and igneous activity that affected the plate since removal of the subducted Farallon plate beneath it. This idea will be tested using physics-based models and comparing results with observations from a range of disciplines. If this new idea is consistent with a wide variety of data, then the geologic community may have a robust and viable solution to the long-standing problem of the uplift of the Colorado Plateau. The project is providing important training for a graduate student in building quantitative models of the Earth and is broadening participation of underrepresented groups in the earth sciences. The computer models and programs developed in this research will be available to the wider geologic community.

该项目整合了科罗拉多高原构造和地貌演化的现有数据，以测试该地区第三纪历史的地球动力学模型。 该模型的核心思想是，科罗拉多高原下面是成分独特的地幔岩石圈，玄武岩成分已耗尽。在这种情况下，岩石圈固有的化学浮力可以解释科罗拉多高原神秘的构造一致性和稳定性。通过比较来自许多不同数据集的数值模型结果约束，可以探索这一想法的地球动力学含义，这些数据集包括：第三纪岩浆模式、热流、地震速度变化、捕虏体、岩石折返以及岩石和地表隆起。这项研究包括明确考虑科罗拉多高原边缘与中部可能不同的构造历史。该项目的主要目标是阐明科罗拉多高原第三纪演化中两个最令人费解的方面——岩石和地表隆起的时间和机制，以及在强烈的岩浆活动和活跃变形时期的相对构造稳定性。影响了美国西部的其他地区。科罗拉多高原隆起的机制和时间是一个长期存在的谜题，对一些最优秀的地质学家提出了挑战，其中包括 J.W.鲍威尔、C.达顿和 G.K.吉尔伯特.该项目为该地区的历史提出了一个新的想法，即科罗拉多高原的隆起与北美板块的化学结构密切相关，并受到自北美板块移除以来影响该板块的强烈加热和火成岩活动的控制。法拉隆板块俯冲到其下方。这个想法将使用基于物理的模型进行测试，并将结果与​​一系列学科的观察结果进行比较。如果这个新想法与各种数据一致，那么地质学界可能会对科罗拉多高原隆起这一长期存在的问题有一个强有力且可行的解决方案。该项目为研究生提供建立地球定量模型的重要培训，并扩大地球科学领域代表性不足群体的参与。本研究开发的计算机模型和程序将可供更广泛的地质界使用。