Collaborative Research: CMG --Quantifying Tectonic and Geomorphic Interpretations of Thermochronometer Data with Inverse Problem Theory

合作研究：CMG——用反问题理论量化测温仪数据的构造和地貌解释

• 批准号: 0724457
• 负责人: Kenneth Farley
• 金额: $ 18.91万
• 依托单位: California Institute of Technology
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-09-01 至 2011-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0724457&HistoricalAwards=false
• 关键词: Collaborative; Research; CMG; Quantifying; Tectonic

The grandeur of mountain topography has for millennia captured the attention of poets, artists, and scientists. How plate tectonic processes of mountain building and mountain erosion by surface processes interact to produce topography over millions of years is now at the forefront of Earth science research. A fundamental question that arises when studying the evolution of mountains is: what did the past topography of mountain ranges look like? This question has proven very difficult to answer. Recent developments in both computer modeling of mountain building and erosional processes, and developments in geochemistry have made progress in reconstructing paleotopography. Advances in new geochemical techniques and mathematics (inverse problem theory) now allow a means of testing computer model predictions with geochemical (thermochronometer) data from rocks exposed at the Earth's surface today. These data record the cooling history of rocks as they are exhumed to the surface by erosion and faulting. This interdisciplinary project is addressing questions and hypotheses that are fundamental to quantifying the evolution of mountain topography including: (1) How can geologically meaningful interpretations of tectonic and geomorphic processes influencing mountain topography be improved from an integration of thermochronometer data, computer modeling, and mathematics? (2) How sensitive are thermochronometer data to different mountain building and erosional processes and how can sampling strategies be optimized to improve interpretations? and (3) What is the magnitude and rate of topographic change that can be resolved from mathematical inversion of thermochronometer data? To address these questions, this project investigates the forward and inverse problems of mountain topographic evolution with a comprehensive model. Coupled 3D thermal, hydrologic, and kinematic computer models are under development in addition to a surface process model accounting for glacial, fluvial, and hillslope erosional processes. The coupled model is used to explore the sensitivity of thermochronometer data to different processes and mathematically invert a dense network of new and existing thermochronometer samples from the southern Coast Mountains, B.C., for the regional paleotopography. Field work is in progress for the collection of additional data. Several novel mathematical techniques are also under development. In particular, a low pass filter technique and a regularized iterative method are being used to solve the notoriously ill-posed backward parabolic equation and large scale, nonlinear inverse heat transport equation. These problems are by nature interdisciplinary and in the forefront of predicting and interpreting thermochronometer data and mountain topography.

几千年来，壮丽的山地地貌吸引了诗人、艺术家和科学家的注意。 板块构造过程中的造山作用和地表过程造成的山体侵蚀如何在数百万年的时间里相互作用，形成地形，现在是地球科学研究的前沿。研究山脉演化时出现的一个基本问题是：过去山脉的地形是什么样的？事实证明，这个问题很难回答。造山运动和侵蚀过程的计算机模拟以及地球化学的发展使古地形的重建取得了进展。新的地球化学技术和数学（反问题理论）的进步，现在允许一种手段来测试计算机模型的预测与地球化学（热时计）数据暴露在地球表面的岩石今天。这些数据记录了岩石因侵蚀和断层作用而被挖掘到地表时的冷却历史。这个跨学科的项目是解决的问题和假设，是根本的定量山地地形的演变，包括：（1）如何可以地质意义上的解释构造和地貌过程影响山地地形改善热时计数据，计算机建模和数学的整合？(2)热时计数据对不同的造山和侵蚀过程有多敏感，如何优化取样策略以改进解释？（3）从热时计数据的数学反演可以解决的地形变化的幅度和速率是多少？ 为了解决这些问题，本项目研究了山地地形演化的正问题和反问题的综合模型。耦合的三维热，水文和运动学的计算机模型正在开发中，除了一个表面过程模型占冰川，河流和山坡侵蚀过程。耦合模型用于探索热时计数据对不同过程的敏感性，并在数学上反演来自不列颠哥伦比亚省南部海岸山脉的新的和现有的热时计样本的密集网络，区域性古地形。正在进行实地工作，以收集更多数据。一些新的数学技术也正在开发中。特别是，低通滤波器技术和正则化迭代方法被用来解决臭名昭著的不适定的向后抛物方程和大规模的，非线性的热输运逆方程。 这些问题本质上是跨学科的，处于预测和解释热时计数据和山区地形的最前沿。