Collaborative Research: The Pleistocene Erosion History of Glaciated Alpine Valleys Interrogated by Apatite 4He/3He Thermochronometry

这项研究将重建详细的历史侵蚀和救济代内的两个伟大的沿海中纬度山脉，海岸山脉的不列颠哥伦比亚省和新西兰的南阿尔卑斯山（峡湾地区）的位置。 深而宽的高山峡谷是第四纪冰川最壮观的遗产之一。 然而，关于这些山谷的侵蚀和地貌发展的总规模和时空格局的具体资料很少。 然而，这些山谷的侵蚀和地貌发育是侵蚀、气候和构造耦合系统演变的核心，这些系统塑造了主要山脉。 获取定量信息，这种山谷的发展超过几百万年的时间尺度和剥露厚度小于2公里，将是一个重大贡献，解决晚新生代过渡到冰川气候是否伴随着增加山谷切口率和增加救济代的问题。这项研究将是一个非常有前途的新的地球化学工具，磷灰石4He/3He热年代学的第一个系统应用。 这种技术是从根本上不同于传统的热年代学方法，在其独特的低温敏感性和它的能力，从单一的矿物颗粒获得冷却的历史。 将检查结果与全球气候变化历史的联系，以及沿着山谷网络纵轴的特征变化模式。 这项研究将确立一种新的地球化学技术的实用性，这种技术有可能广泛应用于地表过程研究和构造学。 该项目将构成初级PI研究计划的重要组成部分，并将成为他新的惰性气体热计时实验室设施的首批科学应用之一。 拟议的工作将构成一个研究生的博士研究和培训的重要组成部分，并将被用作本科班的案例研究。

This research will reconstruct detailed histories of erosion and relief generation at locations within two great coastal mid-latitude mountain ranges, the Coast Mountains of British Columbia and the Southern Alps (Fiordlands region) of New Zealand. Deep and broadly scoured alpine valleys are one of the most spectacular legacies of Quaternary glaciation. However, very little specific information is available about the total magnitudes and the temporal and spatial patterns of erosion and relief development in these valleys. Yet erosion and relief development of these valleys is central to the evolution of the coupled system of erosion, climate, and tectonics that shapes major mountain ranges. Acquiring quantitative information about such valley development over timescales of a few million years and exhumation thicknesses of less than 2 km will be a major contribution toward resolving the question of whether the late Cenozoic transition to glacial climate was accompanied by increased valley incision rates and increased relief generation. This research will be the first systematic application of a very promising new geochemical tool, apatite 4He/3He thermochronometry. This technique is fundamentally different from conventional thermochronometric methods in its sensitivity to uniquely low temperatures and its ability to derive cooling histories from single mineral grains. Results will be examined for connections to the history of global climate change and for characteristic patterns of variation along the longitudinal axes of valley networks. The research will establish the usefulness of a new geochemical technique that has the potential for widespread applications in surface process studies and tectonics. The project will constitute an important part of the research program for a junior PI, and will be one of the first scientific applications of his new noble gas thermochronometry laboratory facility. The proposed work will constitute an important part of a graduate student's doctoral research and training, and will be used as a case study in undergraduate classes.