COLLABORATIVE RESEARCH: Dynamic Response of Bedrock Fluvial Systems to Tectonic Forcing

9725723惠普尔剥蚀卸荷是造山过程中的一种重要力量；剥蚀的速度和模式影响着山带的高度、岩性单元的露头模式，甚至可能影响地壳变形的速度和样式。要分析构造和地表过程的相互作用，需要对基岩水道系统的动力学进行定量的了解。也就是说，在构造活跃的河流地貌中，基岩渠道控制着侵蚀卸荷的速度和模式，因为它们为完成陆面剥蚀的山坡过程设定了下限条件。不幸的是，对河流切入基岩过程的许多方面的定量了解很少，这限制了我们模拟基岩河道系统演变的能力。特别是，需要现场数据来约束：(基岩切割速率，(对构造强迫的瞬时响应模式)，(河道响应时间尺度，(对基岩河道宽度的控制，以及(河道过程(例如，河流到泥石流)过渡的形态后果)。为了努力提高我们模拟构造和地表过程之间相互作用的能力，我们提议在三个野外地点研究基岩渠道系统：加利福尼亚州北部国王山脉的沿海排水系统，纽约指湖地区的冰川后沟壑，以及阿拉斯加万烟谷的刀溪。我们之所以选择这些地点，是因为每个地点的气候和岩性在空间上是不变的，每个地点的隆起和气候历史都相对受到很好的约束，并且每个地点都包含指示切割(例如，层阶地)和构造扰动(例如，过陡的溪段)的地貌，这为评估切割速度和对构造强迫的瞬时响应模式提供了一种手段。我们将利用从对比分析中获得的数据，通过一系列的正演和反演(包括二维剖面和三维地貌演变模型)，对L现有的基岩河道演变数学模型施加定量约束。研究结果将对基岩河道系统的演化过程有一个更全面的了解，并为分析地貌演变以及构造、气候和地表过程的相互作用提供了一个改进的数学框架。

9725723 Whipple Erosional unloading is an important force in orogenic processes; the rates and patterns of erosion influence the heights of mountain belts, outcrop patterns of lithologic units, and, perhaps, the rates and styles of crustal deformation. Analysis of the interactions of tectonic and surficial processes requires quantitative understanding of the dynamics of bedrock channel systems. That is, in tectonically active fluvial landscapes bedrock channels control the rates and patterns of erosional unloading because they set the lower boundary condition for hillslope processes that accomplish land surface denudation. Unfortunately, little is known quantitatively about many aspects of the process of river incision into bedrock, and this limits our ability to model the evolution of bedrock channel systems. In particular, field data are needed to constrain: ( rates of bedrock incision, ( Patterns of transient response to tectonic forcing, ( Channel response timescales, ( Controls on bedrock channel width, and ( Morphological consequences of transitions in channel processes (e.g., fluvial to debris flow). In an effort to improve our capabilities to model interactions between tectonic and surface processes, we propose to examine bedrock channel systems at three field sites: coastal drainage's of the King Range of northern California, post-glacial gullies in the Finger Lakes region of New York, and Knife Creek in the Valley of Ten Thousand Smokes in Alaska. We chose these sites because climate and lithology are spatially invariant in each, uplift and climatic histories of each are relatively well-constrained, and each contains landforms indicative of incision (e.g., strath terraces) and tectonic disturbance (e.g., oversteepened stream segments) that provide a means of assessing incision rates and patterns of transient response to tectonic forcing. We will use data obtained from this comparative analysis to place quantitative constraints on an existing mathematical mode l of bedrock channel evolution through a series of forward and inverse modeling exercises (both 2-D profile and 3-D landscape evolution models). The results will provide a more complete understanding of processes in bedrock channel systems and an improved mathematical framework for the analysis of landscape evolution and the interaction of tectonic, climatic and surficial processes.