RUI: Fluvial Terraces: A Tool for Integrating Geomorphic Processes, Climatic and Tectonic Events, and Landscape Development

RUI：河流阶地：整合地貌过程、气候和构造事件以及景观开发的工具

• 批准号: 8917116
• 负责人: Dorothy Merritts
• 金额: $ 10.07万
• 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: 1990
• 资助国家: 美国
• 起止时间: 1990-02-15 至 1992-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=8917116&HistoricalAwards=false
• 关键词: RUI; Fluvial; Terraces; Tool; Integrating

This is a geomorphic investigation of fluvial processes in an area in which tectonic activity varies between river basins, and climate varies with time among the basins. Tectonic controls will dominate terrace formation in high uplift rate regions, and climatic controls will gain increasing importance as uplift rate declines. We propose to test this hypothesis on the basis of differences and similarities in the terrace sequences of three moderate size rivers developed in argillaceous sandstone in coastal northern California. Present climatic controls on amount and intensity of precipitation and temperature are very similar for each drainage basin, although these parameters have varied with late Cenozoic climatic perturbations that ultimately drove the rise and fall of eustatic sea level. Base-level processes related to relative rise of the land mass vary by an order of magnitude from the southernmost to the northernmost rivers. Fieldwork in each watershed will consist of continuous surveying and mapping of the longitudinal profiles of erosional terraces, depositional terraces, and the modern channel and floodplain. Seismic refraction studies will quantify depth of fill where not observable. The chronology of terrace formation will be constrained by radiometric dating of organic material from alluvial sediments either resting upon erosional terraces, or within deposits that comprise depositional terraces. This work will allow quantification of the nature and rates of propagation of channel incision and valley in-filling in response to changing climate and long-term tectonism. Comparison of the results for the three rivers, and thus separation of tectonic and climatic controls, should allow: 1) better understanding of the nature of fluvial response to change, 2) interpreting the environmental significance of strath versus fill terraces, and of preserved flights of terraces in general, and 3) integrating an understanding of geomorphic processes with models of landscape evolution.

这是对河流盆地构造活动变化的区域中河流过程的地貌研究，气候随着盆地的时间而变化。 构造控制将占主导地位的高升高率区域的露台形成，随着升高率下降，气候控制将提高重要性。 我们建议根据加利福尼亚沿海地区的Argilaceous砂岩开发的三个中等大小河流的露台序列的差异和相似性来检验这一假设。 对于每个排水盆地，目前对降水量和温度强度的气候控制非常相似，尽管这些参数随着新生代的气候扰动而变化，最终驱动了Eustatic Sea水平的上升和下降。 与土地质量相对上升有关的基础级别的过程因最南端到最北端的数量级而异。 每个流域中的实地调查将包括对侵蚀露台，沉积露台以及现代渠道和洪泛区的纵向概况的连续测量和映射。 地震折射研究将在无法观察到的情况下量化填充深度。 露台形成的年代学将受到来自侵蚀露台上的冲积沉积物或包含沉积露台的沉积物内的有机材料的辐射测定。 这项工作将允许量化通道切口和山谷的传播性质和速率，以应对气候变化和长期构造的响应。 比较三条河流的结果，从而将构造和气候控制的分离允许：1）更好地理解河流反应对变化的性质，2）解释Strath与填充露台的环境意义，以及一般而言的露台飞行，以及一般而言的3），将对地球形态的理解与地质进化的模型整合在一起。