Collaborative Research: Exploring the tempo of exhumation and relief development to investigate mantle-to-surface connections around the Yellowstone hotspot

合作研究：探索折返和地貌发育的节奏，以调查黄石热点周围地幔与地表的联系

• 批准号: 2126373
• 负责人: Marissa Tremblay
• 金额: $ 5.41万
• 依托单位: Purdue University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-01-01 至 2024-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2126373&HistoricalAwards=false
• 关键词: Collaborative; Research; Exploring; tempo; exhumation

This award is funded in whole or in part under the American Rescue Plan Act of 2021 (Public Law 117-2).Yellowstone is an area where a mantle hotspot upwells beneath the continent causing volcanism and the region’s iconic geothermal features. In addition, the passage of the Yellowstone hotspot beneath the area is suggested to have caused larger scale landscape change by uplifting the regional topography. This project will test that theory by quantifying the erosion history of the Gallatin River, southwest Montana, over the last 6+ million years. The nature and strength of connections between mantle dynamics and Earth’s surface remains a broad question within the field of tectonics, and Yellowstone is an ideal location to study these interactions. The Gallatin River drains off the Yellowstone Plateau and records how the landscape has uplifted, eroded, and changed in response to the arrival of the Yellowstone hotspot in the region. Quantitative estimates of the erosion history on the timescales of tens of thousands to millions of years will be used to test hypotheses about which geodynamic processes contributing to topographic uplift. Results from the project will advance our understanding of the formation of the landscape in the Yellowstone region, an area that receives millions of visitors each year. In addition, the project supports a geoscience internship for underserved high school students from Idaho aimed at increasing the number of students who attend college and pursue technical degrees. The project also supports the training of graduate and undergraduate students at three institutions and helps to advance the careers of two early-career women faculty members. The overall goal of this project is to track the rates and evolution of incision, exhumation, and topographic relief in the Gallatin River drainage basin in southwest Montana during the approach and arrival of the Yellowstone hotspot in the region. The mountainous upper portion of the drainage is actively exhuming, whereas the lower portion contains a Miocene to Pleistocene sedimentary record of this exhumation, which is recently being incised. Bedrock low temperature thermochronology will be combined with detrital thermochronology from the basin and luminescence dating of river terraces to create a complete record of the tempo of incision and exhumation across timescales. These and other geologic observations will be integrated into a landscape evolution model to test hypotheses for patterns and drivers of surface uplift in the region. Research components include: 1) Apatite (U-Th)/He and 4He/3He thermochronology on valley to ridge transects of Cretaceous and Eocene intrusive rocks in the upper Gallatin drainage and integration with geologic constraints to quantify Cenozoic exhumation and relief evolution; 2) Mapping and luminescence dating of terraces along the transect of the Gallatin River to constrain Quaternary incision and deformation; 3) Detrital apatite fission track, U-Pb, and luminescence dating from Miocene and Quaternary sediments in the Gallatin valley to quantify exhumation rates over that timespan; and 4) Integration of geologic and chronologic data into a numerical landscape evolution model to test hypotheses and quantify magnitudes of surface uplift using an inversion scheme. Students ranging from high school to graduate level will be directly involved in this research, including through a summer internship program where underprivileged high school students will participate in research at the University of Idaho.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.

该奖项全部或部分由《2021年美国救援计划法案》（公法117-2）资助。黄石是一个地幔热点在大陆下方上涌的地区，导致火山活动和该地区标志性的地热特征。此外，该地区下方的黄石热点通道被认为通过抬升区域地形而引起了更大规模的景观变化。这个项目将通过量化蒙大拿州西南部加勒廷河在过去600多万年的侵蚀历史来检验这一理论。地幔动力学和地球表面之间联系的性质和强度在构造学领域仍然是一个广泛的问题，而黄石公园是研究这些相互作用的理想地点。加拉廷河从黄石高原流出，记录了该地区的景观如何随着黄石热点的到来而上升、侵蚀和变化。在数万年至数百万年的时间尺度上对侵蚀历史的定量估计将用于检验关于哪些地球动力学过程有助于地形隆起的假设。该项目的结果将促进我们对黄石地区景观形成的理解，该地区每年接待数百万游客。此外，该项目还为爱达荷州服务不足的高中生提供地球科学实习，旨在增加上大学并攻读技术学位的学生人数。该项目还支持三所大学的研究生和本科生的培训，并帮助两名早期职业女性教员的职业发展。该项目的总体目标是跟踪蒙大拿州西南部加拉廷河流域在该地区黄石热点接近和到达期间的切割、挖掘和地形起伏的速率和演变。该流域的山地上部正在进行积极的挖掘，而下部则包含了此次挖掘的中新世至更新世的沉积记录，最近正在进行切割。基岩低温热年代学将与盆地碎屑热年代学和河流阶地的发光定年相结合，形成跨时间尺度的切口和挖掘速度的完整记录。这些和其他地质观测结果将被整合到一个景观演化模型中，以检验该地区地表隆起的模式和驱动因素的假设。研究内容包括：1)对上加勒廷流域白垩系和始新统侵入岩的谷岭样带进行磷灰石(U-Th)/He和4He/3He热年代学研究，并结合地质约束，量化新生代发掘和地形演化；2)加勒廷河样带阶地填图与发光测年，约束第四纪切割与变形；3)利用Gallatin谷中新世和第四纪沉积物的碎屑磷灰石裂变径迹、U-Pb和发光定年，量化该时期的出土率；4)将地质和年代学数据整合到景观演化数值模型中，利用反演方案检验假设并量化地表抬升幅度。从高中到研究生水平的学生将直接参与这项研究，包括通过暑期实习计划，贫困的高中学生将参加爱达荷大学的研究。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。