Recent deformation across the Basin and Range: from kinematics to mechanics

我请求拨款调查内华达州盆地山脉省的山脉生长情况。在这个省的孤立地点，有证据表明，在过去的300万至400万年里，推动这些山脉隆起的断层活动有所增加，但目前还不清楚这种断层活动的增加是广泛的还是局部的。了解这种活动的性质将揭示推动这种活动增加的过程。我计划使用两种类型的数据来研究这些过程。首先，我将使用一种“自上而下”的方法，根据地形特征的景观，以确定断层活动发生变化时，在个别山脉。这种方法背后的原理是，当断层活动增加时，河流变陡并被切断，这种切割可以使用数字高程模型来测量。其次，我将联合收割机这些观察与“自下而上”的方法，基于地球化学方法，告诉我们岩石的热历史，因为他们通过侵蚀接近地球表面。当岩石由于侵蚀而接近地球表面时，它们会冷却，这种冷却被保存在放射性衰变产生的氦原子的浓度中。在高温下，氦通过扩散损失，但随着温度降低，扩散速率也降低，氦被保留下来。我们可以测量磷灰石单晶中氦的含量和分布，并以此推断岩石接近表面时的冷却历史。通过结合“自下而上”的方法和“自上而下”的方法，它可以估计断层活动的准确性增加，但也获得了深入了解侵蚀的过程。此外，丰富的数字高程数据使我们能够同时处理多个范围，从而测量断层活动增加的程度。最后，通过使用侵蚀和构造过程如何相互作用的数值模型综合这些数据集和观测结果，我们可以了解驱动断层活动的力量，并可能预测未来的断层活动。

I request funds to investigate the growth of mountain ranges across the Basin and Range Province, Nevada. At isolated locations across this province there is evidence that activity on faults driving the uplift of these mountain ranges has increased within the last 3-4 million years, however it is unclear if this increased fault activity is widespread or localised. Understanding the nature of this activity will reveal the processes that are driving this increased activity. I plan to use two types of data to investigate these processes. First, I will use a "top-down" approach, based on topographic signatures of the landscape to identify when fault activity changed at individual mountain ranges. The principle behind this approach is that when fault activity increases, rivers steepen and cut down, and this incision can be measured using digital elevation models. Second, I will combine these observations with a "bottom-up" approach, based on geochemical methods that tell us about the thermal history of rocks as they approach Earth's surface through erosion. As rocks approach the Earth's surface due to erosion, they cool and this cooling is preserved in the concentration of helium atoms that are produced by radioactive decay. At high temperatures, helium is lost through diffusion, but as temperatures decrease, the rate of diffusion also decreases and helium is retained. We can measure the amount, and distribution of helium, within a single crystal of apatite and use this to infer the cooling history of a rock as it approaches the surface. By combining the "bottom-up" approach and "top-down" approach it is possible to estimate fault activity with increased accuracy, but also gain an insight into the processes of erosion. Furthermore, the abundance of digital elevation data allows us to tackle many ranges at the same time and therefore, measure the extent of increased fault activity. Finally, by synthesizing these datasets and observations using numerical models of how erosion and tectonic processes interact, we can understand the forces driving fault activity, and potentially predict fault activity in the future.