EAGER: Cosmogenic Nuclide Measurement of Surface Uplift Rate and Paleoelevation

理解驱动大陆大高原和山脉带隆起的构造力取决于对这些地理域中的表面隆起的速度的测量，从而确定地表高度随时间的变化。不同的抬升模型预测了不同的速率或过去的海拔。各种方法被用来测量抬升速率和古海拔，取得了不同的成功，具有不同程度的不确定性。在这个项目中，研究小组的目标是测试一种新的、新颖的技术，这种技术有可能减少这些不确定性，这可能会更好地限制对地球内部产生这些主要特征的基本力的理解。该方法依赖于对宇宙成因核素的精确测量，这些核素是在暴露于宇宙射线的矿物中产生的。这一探索性项目依赖于宇宙成因核素产量对海拔的依赖，以确定隆起率和古海拔，对南美洲一个受限制的野外环境的样品进行了测试。该项目中一名博士后研究员的参与促进了STEM工作队伍的发展。这一探索性项目开发了一种使用陆地宇宙成因核素(TCN)测量地表隆起速率的新方法。由于该方法在规定的时间尺度上测量抬升速率，因此它还可以得出古海拔。该方法利用了TCN生产率与海拔高度的良好相关性。前提是一个稳定的表面将总是比最近被抬升到相同海拔的其他相同的表面具有更高的TCN浓度。由于大多数TCN生产发生在较低的海拔，因此生产率较低，因此隆升的表面表现出这种缺陷。赤字的大小取决于产量的提高速度和持续时间。该方法通过使用多个样品和多个同位素对，以及独立的地表年龄约束，在规定的时间间隔内同时求解侵蚀速率和地表隆起速率，以获得精度。为了评估这项技术的精度和适用性，研究小组将采样和测量阿塔卡马沙漠(智利和秘鲁)中新世至上新世点火沸石的TCN浓度(21Ne、10Be和26Al)，那里有独立确定的地表隆起数据来验证TCN结果。其目的是了解(1)该方法如何在一定的提升率范围内执行；(2)增加样本数量如何减少不确定性；以及(3)该方法是否在不同的时间尺度和使用不同的同位素对上保持内部一致。这项研究将加强博士后培训，从而有助于培养一支具有全球竞争力的STEM劳动力队伍，并与德国波茨坦的GeoForschungsCenter开展重要的国际合作。一项成功的成果将是一种新的新的古高程测量工具，它将广泛适用于大部分或地球-S表面，并将改变确定活动造山带或因动态地形或冰川均衡调整而隆起的地区的古海拔和地表隆升速率的能力。

Understanding the tectonic forces that drive uplift of large continental plateaus and mountain belts depends on measurement of how fast the surfaces in those physiographic domains have been uplifted and, consequently, how surface elevation has changed with time. Different models of uplift predict different rates or past elevations. Various methods have been used to measure uplift rates and paleoelevation to varying success and with varying degrees of uncertainty. In this project, the research team aims to test a new and novel technique that has the potential to reduce these uncertainties, which could potentially better constrain the understanding of the fundamental forces operating within the Earth that generate these major features. The method relies on precise measurement of cosmogenic nuclides, which are produced in minerals during exposure to cosmic rays. This exploratory project relies on the dependence of cosmogenic nuclide production on elevation to determine uplift rates and paleoelevation in a test on samples from a well-constrained field setting in South America. The engagement of a post-doctoral fellow in the project promotes development of the STEM workforce.This exploratory project develops of a new measure of surface uplift rate using terrestrial cosmogenic nuclides (TCN). Because the method measures uplift rate over a defined timescale, it also yields paleoelevation. The method exploits the well-established dependence of TCN production rates on elevation. The premise is that a stable surface will always have a higher TCN concentration than an otherwise identical surface that has been recently uplifted to the same elevation. Uplifting surfaces exhibit this deficit because most TCN production occurred at a lower elevation - and therefore lower production rate. The size of the deficit depends on the uplift rate and duration of production. The method solves for both erosion rate and surface uplift rate simultaneously over a defined time interval by using multiple samples and multiple isotope pairs, along with independent surface age constraints, in order to gain precision. In order to assess the precision and applicability of this technique, the research team will sample and measure TCN concentrations (21Ne, 10Be, and 26Al) for Miocene to Pliocene ignimbrites of the Atacama Desert (Chile and Peru), where independently determined surface uplift data are available to verify TCN results. The goal is to understand (1) how the method performs at a range of uplift rates; (2) how increasing the number of samples may reduce uncertainty; and (3) whether the approach is internally consistent over different timescales and using different isotope pairs. The research would enhance post-doctoral training thus contributing to the development of a globally competitive STEM workforce and involve the significant international collaboration with the GeoForschungsZentrum in Potsdam, Germany. A successful outcome will be a new novel paleoaltimetry tool that will be widely applicable over much or the Earth?s surface and will transform the ability to determine paleoelevation and surface uplift rates in active orogens or areas experiencing uplift due to dynamic topography or glacial isostatic adjustment.