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

该项目整合了科罗拉多高原构造和地文演化的现有数据，以测试该地区第三纪历史的地球动力学模型。 该模型的核心是认为科罗拉多高原的下面是成分不同的地幔岩石圈，其中玄武岩成分减少。在这种情况下，岩石圈的内在化学浮力可以解释神秘的构造连贯性和稳定性的科罗拉多高原。地球动力学的影响，这一想法正在探讨通过比较数值模型的结果来自许多不同的数据集，包括：第三纪岩浆模式，热流，地震速度的变化，捕虏体，岩石折返，岩石和地表隆起的约束。这项研究包括明确考虑可能不同的构造历史的边缘与中部的科罗拉多高原。该项目的主要目标是阐明科罗拉多高原第三纪演化中最令人困惑的两个方面--其岩石和地表隆起的时间和机制，以及在剧烈的岩浆活动和活跃的变形影响美国西部其他地区的时期其相对构造稳定性。科罗拉多高原隆起的机制和时间是一个长期存在的谜团，它挑战了一些最优秀的地质学家，包括J. W.鲍威尔角达顿和G. K.吉尔伯特。该项目为该地区的历史发展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，并受到强烈的加热和火成岩活动的控制，这些活动影响了该板块，因为俯冲的法拉隆板块被移走了。如果这个新想法与各种各样的数据相一致，那么地质学界可能会对科罗拉多高原隆起的长期问题提出一个可靠而可行的解决方案。该项目正在为一名研究生提供建立地球定量模型的重要培训，并正在扩大代表性不足的群体对地球科学的参与。在这项研究中开发的计算机模型和程序将提供给更广泛的地质界。

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.