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

[9725348]侵蚀卸荷是造山过程中的重要力量；侵蚀的速率和模式影响着山带的高度、岩性单元的露头模式，也许还影响着地壳变形的速率和样式。对构造和地表过程相互作用的分析需要对基岩河道系统动力学的定量理解。也就是说，在构造活跃的河流景观中，基岩通道控制着侵蚀卸荷的速率和模式，因为它们为完成地表剥蚀的山坡过程设定了下边界条件。不幸的是，我们对河流切入基岩过程的许多方面所知甚少，这限制了我们模拟基岩河道系统演化的能力。特别是，需要实地数据来约束：（基岩切割速率）、（构造强迫的瞬态响应模式）、（河道响应时间尺度）、（基岩河道宽度的控制）和(河道过程转换的形态学后果（例如，河流到泥石流）。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，我们建议在三个实地地点检查基岩水道系统：加利福尼亚北部国王山脉的沿海排水，纽约芬格湖区的冰川后沟渠，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都是不变的，每个地点的隆升和气候历史都受到相对较好的约束，每个地点都包含指示切口（例如，河床梯田）和构造扰动（例如，过陡的溪流段）的地形，这些地形提供了评估切口速率和构造强迫瞬态响应模式的手段。我们将利用从对比分析中获得的数据，通过一系列正演和反演建模练习（包括二维剖面和三维景观演化模型），对现有的基岩河道演化数学模型施加定量约束。这些结果将为基岩河道系统的过程提供更完整的理解，并为景观演化和构造、气候和地表过程相互作用的分析提供一个改进的数学框架。

9725348 Merritts 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 mod el 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.