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

RUI：合作研究：基岩河流系统对构造强迫的动态响应

• 批准号: 9725348
• 负责人: Dorothy Merritts
• 金额: $ 7.73万
• 依托单位: Franklin and Marshall College
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-01-01 至 2001-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9725348&HistoricalAwards=false
• 关键词: RUI; COLLABORATIVE; RESEARCH; Dynamic; Response

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.

9725348 Merritts 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山脉的高度、岩性单元的露头模式，或许还影响地壳变形的速率和类型。 分析构造和地表过程的相互作用需要定量了解基岩河道系统的动力学。 也就是说，在构造活跃的河流景观中，基岩河道控制着侵蚀卸载的速率和模式，因为它们为实现陆地表面剥蚀的山坡过程设定了下边界条件。 不幸的是，人们对河流切入基岩过程的许多方面知之甚少，这限制了我们模拟基岩河道系统演化的能力。 特别是，需要现场数据来约束：（基岩切割速率，（对构造强迫的瞬态响应模式，（河道响应时间尺度），（对基岩河道宽度的控制，以及（河道过程转变的形态后果（例如，河流）为了提高我们模拟构造和地表过程之间相互作用的能力，我们建议检查三个现场地点的基岩河道系统：金山脉的沿海排水系统。加利福尼亚州北部、纽约手指湖地区的冰川后沟壑和阿拉斯加万烟谷的刀溪我们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，每个地点的隆起和气候历史都是不同的。相对良好的约束，并且每个都包含指示切口（例如，地层阶地）和构造扰动（例如，过度陡峭的河流段）的地形提供了一种评估切割率和对构造强迫的瞬态响应模式的方法。 我们将使用从比较分析中获得的数据，通过一系列正向和逆向建模练习（2 维剖面和 3 维景观演化模型）对基岩河道演化的现有数学模型进行定量约束。 研究结果将为基岩水道系统的过程提供更全面的理解，并为分析景观演化以及构造、气候和地表过程的相互作用提供改进的数学框架。