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.

美国西部的科罗拉多高原融合了壮观的自然景观，例如大峡谷，锡安和拱门国家公园。该地区位于1亿年前的海平面，现在处于海拔约2公里的海拔。但是，该地区表面升高的原因尚不清楚。该项目将调查在过去几十年中引起了考虑辩论的几种提议机制之一的可行性。具体而言，这项研究将解决来自太平洋板块俯冲碎片的水的水合是否会降低其密度并导致地面上升。这是基于相同的原理，这些原则控制着高度高的木材将在水中漂浮的高度。这项研究的结果可能具有深远的影响，因为在较宽的岩石山区和高平原上高海拔的偶然机制（包括丹佛，包括“英里高城市”）可能是由于过程也影响了安第斯山脉等其他山区地区。该项目的所有活动中的常见教育主题包括研究生和本科教育和培训，与法国研究人员的国际合作以及地球科学中代表性不足的少数族裔学生的增强。该项目将调查过度变化改变了矿物质上的矿物质构成和相关的层次层面的矿物质和相关密度，并构成了贡献的效果。这项研究将整合来自大约2500万历史的纳瓦霍火山场的一套地壳异岩的新岩石学，地质和稳定的同位素研究。将开发出科罗拉多州中央高原地壳的水合后（当今）模型，该模型将结合了异种石的新观察结果，并确保与现代地震和其他地球物理数据的兼容性。这将与基于详细的异种石分析的地壳的杂技学模型一起评估。计算出的液压前和后密度差异将用于限制对改变的潜在等静力响应。该项目由构造计划和地球科学系的岩石学和地球化学计划共同资助。该奖项反映了NSF的法定任务，并通过使用基金会的知识分子和更广泛的影响评估审查标准来评估，被认为是珍贵的支持。