Collaborative Research: Testing Hypotheses for Neotectonic Mantle-Driven Surface Uplift of the Colorado Plateau Region

本项目将研究大峡谷地区如何对上地幔对流驱动的地表隆起作出反应。这项研究的目标是利用大陆尺度的科罗拉多河系统作为一个暴露良好的现场实验室和敏感的衡量复杂的相互作用之间的断层，火山活动，隆起，河流动力学和气候过程，共同塑造这个经典地区的景观。将使用的方法和途径包括各种测年技术（玄武岩流Ar-Ar测年、钙钛矿胶结物U系测年、砾石宇宙成因年龄、年轻阶地的光释光测年），这些技术将用于确定阶地砾石年龄。这些沉积物保留了过去的景观位置，因此可以用来衡量隆起，切割率和不断变化的景观。目的是测试的想法，地幔流和浮力修改驱动表面隆起和长波长的表面变形的科罗拉多高原，通过确定是否有空间模式的切口率模仿mantle anomalies.This研究将测试的想法，崎岖的地形大峡谷和美国西部正在重新塑造今天的上地幔对流。这种物质和流体的运动发生在地表以下数百公里处，涉及由流动岩石、部分熔体和流体组成的热浮力软流层的上涌区域，以及寒冷致密的北美岩石圈的下涌区域。这种隆起似乎是造成科罗拉多高原地区在过去1000万年间发生的400-1000米的地表隆起的原因。这相当于该地区目前平均海拔的25-50%。这一提升仍在继续。该研究计划涉及教学与研究的整合，以及对众多研究生和本科生的指导，包括来自美国西南部的西班牙裔和美洲原住民学生。该项目将导致改进的书面和网络材料科罗拉多高原隆起和峡谷雕刻，将链接到地球科学解释高原公园通过国家公园管理局网页和新开放的时间之路地球科学教育展览在大峡谷国家公园。

This project will study how the Grand Canyon region is responding to surface uplift driven by upper mantle convection. The goal of the research is to use the continental-scale Colorado River system as a well exposed field laboratory and sensitive gauge of the complex interplay between the processes of faulting, volcanism, uplift, river dynamics, and climatic processes that, collectively, are shaping the landscape of this classic region. The methods and approaches to be used include a variety of dating techniques (Ar-Ar dating of basalt flows, U-series dating of travertine cements, cosmogenic ages of gravels, OSL dates on young terraces) that will be used to determine terrace gravel ages. These deposits preserve past landscape positions and hence can be used to gauge uplift, incision rates, and changing landscapes. The aim is to test the idea that mantle flow and buoyancy modification are driving surface uplift and long wavelength surface deformation of the Colorado Plateau by determining whether or not there are spatial patterns in incision rate that mimic mantle anomalies.This research will test the idea that the rugged topography of the Grand Canyon and western United States are being re-shaped today by upper mantle convection. This movement of mass and fluid is taking place hundreds of kilometers below the surface and involves upwelling domains of hot buoyant asthenosphere that consists of flowing rock, partial melt, and fluid, as well as downwelling domains of cold dense North American lithosphere. The upwellings appear to be responsible for 400-1000 meters of surface uplift that has taken place in the Colorado Plateau region in the last 10 million years. This amounts to 25-50% of the present average elevation of the region. This uplift is still ongoing. The research plan involves integration of teaching with research and mentorship of numerous graduate and undergraduate students, including Hispanic and Native American students from the southwestern U.S.. The project will lead to improved written and web materials on Colorado Plateau uplift and canyon carving that will be linked to geoscience interpretation for Plateau Parks via the National Park Service web pages and the newly opened Trail of Time Geoscience Education Exhibition at Grand Canyon National Park.