Collaborative Research: Quantifying crustal hydration effects in the Colorado Plateau from xenoliths

合作研究：通过捕虏体量化科罗拉多高原的地壳水合效应

基本信息

批准号：
1937343
负责人：
Kevin Mahan
金额：
$ 28.1万
依托单位：
University of Colorado at Boulder
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2020
资助国家：
美国
起止时间：
2020-07-01 至 2024-06-30
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1937343&HistoricalAwards=false
关键词：
Collaborative Research Quantifying crustal hydration

项目摘要

The Colorado Plateau in the western United States incorporates spectacular natural landscapes, such as Grand Canyon, Zion, and Arches National Parks. This region was at sea level 100 million years ago and now sits at an elevation of about 2 kilometers above sea level. However, the reasons why surface elevations in this region increased are not well understood. This project will investigate the viability of one of several proposed mechanisms that have generated considerable debate over the last several decades. Specifically, this research will address whether hydration of Earth’s crust by water derived from a subducted fragment of the Pacific oceanic plate reduced its density and caused the ground surface to rise. This is based on the same principles that govern how high blocks of wood with different densities will float in water. The results of this research could have far-reaching implications because causal mechanisms for high elevations in the broader Rocky Mountain region and High Plains (including Denver, the “Mile High City”) may be due to processes that also affect other mountainous regions such as the Andes. Common educational themes among all of the activities in this project include graduate and undergraduate education and training, international collaborations with researchers in France, and enhancement of underrepresented minority students in Earth science.This project will investigate the hypothesis that hydrous alteration changed the mineralogical makeup and associated density structure of the Colorado Plateau lower crust and contributed significantly to its 2 kilometers surface uplift via isostatic adjustment. This research will integrate new petrologic, geochronologic, and stable hydrogen isotopic studies of a suite of crustal xenoliths from the approximately 25-million-year-old Navajo Volcanic Field. A post-hydration (present-day) model of the central Colorado Plateau crust will be developed that incorporates new observations from xenoliths, and ensures compatibility with modern seismic and other geophysical data. This will be evaluated along with a pre-hydration model for the crust that is based on detailed xenolith analyses. Calculated differences in pre-and post-hydration model densities will be used to constrain the potential isostatic response to alteration.This project is jointly funded by the Tectonics program and the Petrology & Geochemistry program in the Division of Earth Sciences.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.

西方州的科罗拉多州高原融合了大自然的景观，例如大峡谷和拱门自然公园。不理解的是，讨厌的辩论是从太平洋板块密度的俯冲碎片中得出的几十年。在水中，这项研究的结果可能会在较宽的岩石山区军团和高平原上具有高海拔的远处机制。”排名的所有活动包括和本科教育和培训，与法国研究人员的国际合作，以及代表不足的学生，地球科学的学生。较低的地壳并通过等静止调节促进其2公里的表面隆起。观察om xenoliths，并确保与现代地震和其他地球物理数据的兼容性以及基于Designolith分析的地壳的预缩合模型。计划和地球化学RAM在地球科学法定任务部中，通过使用Foun dation的知识分子优点和更广泛的影响审查标准，通过评估值得支持。