Collaborative Research: Transient Landscapes, Temporally Variable Erosion Rates, and the Impact of Glaciation and Climate Change on Landscape Morphodynamics

合作研究：瞬变景观、随时间变化的侵蚀率以及冰川作用和气候变化对景观形态动力学的影响

基本信息

批准号：
1123688
负责人：
James Spotila
金额：
$ 31.89万
依托单位：
Virginia Polytechnic Institute and State University
依托单位国家：
美国
项目类别：
Continuing Grant
财政年份：
2012
资助国家：
美国
起止时间：
2012-01-01 至 2015-12-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1123688&HistoricalAwards=false
关键词：
Collaborative Research Transient Landscapes Temporally

项目摘要

Collaborative Research: Transient landscapes, temporally variable erosion rates, and the impact of glaciation and climate change on landscape morphodynamics.James Spotila, Virginia TechLewis Owen, University of CincinnatiOver the past two decades, geologists have determined that erosion and climate, processes that work at the Earth?s surface, directly influence plate tectonics and mountain building, processes linked to the dynamics of Earth?s interior (crust and upper mantle). One climatic variation that has enormous influence of the effectiveness of erosion is temperature, as represented by the vast difference between erosion by rivers (i.e. fluvial erosion) and glaciers. A profound global acceleration in erosion several million years ago has been ascribed in countless studies to the onset of global cooling and the expansion of glaciers. This has lead to the idea that glaciers are absolutely efficient agents of erosion, acting like buzz saws that can erode rock as fast as plate tectonics pushes up mountains. Yet when this is examined in detail, there are numerous observations that suggest the behavior is more complex. We have identified heavily glaciated mountain ranges in tectonically active areas that may be eroding very slowly. There are also glaciated mountain ranges that may have experienced rapid erosion, despite being dominated by frozen beds (normally linked to slow erosion) and a lack of tectonic uplift. These observations suggest that there may be complex conditions that operate as thresholds for the onset of the extremely rapid, efficient glacial erosion. To test this, we will quantify what factors act as thresholds that control the response of mountain erosion to glaciation, including the factors of rock uplift rate, precipitation, and tectonic relief. This will be accomplished by expanding the case knowledge of glacial erosion controls, by quantifying chronologies of erosion rate over a range of timescales and erosive depths in four very different mountainous regions that span a range of conditions, including the Chugach and Kenai Ranges in Alaska, northwest Scotland, and the Presidential Range of New England. In each location we will test whether erosion accelerated with the onset of a specific stage of glacial development, by measuring erosion rates using several methods of radiogenic helium thermochronology (million year timescale) and cosmogenic dating, optically stimulated luminescence, and sedimentary records (spanning ten thousand to a hundred years). By contributing to our understanding of erosion, climate, and tectonics, we will in effect help satisfy an innate human curiosity for how the landscape around us formed. We will also enable a better, more predictive understanding for how glacial and alpine landscapes respond to climate change, which is of timely, practical importance. In parallel with our research, our educational and museum outreach program will serve to connect to both students and the general public, kindling curiosity for Earth processes while conveying an experience of how geoscience problems are framed and tested through experimentation.

协作研究：瞬时景观，暂时性变化的侵蚀率以及冰川和气候变化对景观形态学的影响。地球的内部（地壳和上地幔）。侵蚀有效性具有巨大影响的一种气候变化是温度，如河流（即河流侵蚀）和冰川之间的巨大差异所示。几百万年前，全球侵蚀中的一个深刻的加速已被归因于无数研究，以开始全球冷却和冰川的扩张。这导致了这样一个想法，即冰川是绝对有效的侵蚀剂，其作用像嗡嗡声锯，可以像板块构造一样快地侵蚀岩石。然而，当对此进行详细检查时，有许多观察结果表明该行为更加复杂。我们已经确定了构造活跃地区的大量冰川山脉，这些山脉可能非常缓慢地侵蚀。尽管受到冷冻床（通常与缓慢的侵蚀有关）和缺乏构造隆起的态度，但也可能经历了冰川山脉的速度快速侵蚀。这些观察结果表明，对于极快，有效冰川侵蚀的发作，可能存在复杂的条件作为阈值。为了测试这一点，我们将量化哪些因素是控制山侵蚀对冰川的响应的阈值，包括岩石上升速率，降水和构造的因素。这将通过扩展冰川侵蚀控制的案例知识来实现，通过在四个跨越各种条件的山区区域中量化侵蚀率的时间顺序，包括跨越各种条件的山区，包括Chugach和Kenai Ranges在阿拉斯加，西北苏格兰，西北苏格兰以及新英国总统范围。在每个位置，我们将通过使用几种放射性氦热量学方法（百万年度时间表）和宇宙源性测量，光学刺激的发光和沉积记录（超过十万年至一百年）来测量冰川发育特定阶段的侵蚀是否加速侵蚀。通过为我们对侵蚀，气候和构造学的理解做出贡献，我们实际上将有助于满足人类对我们周围环境如何形成的好奇心。我们还将对冰川和高山景观如何应对气候变化的反应更好，更具预测性的理解，这是及时，实际上重要的。与我们的研究同时，我们的教育和博物馆外展计划将与学生和公众建立联系，对地球过程的好奇心，同时传达了如何通过实验进行地球科学问题的经验。