Roe,G.H., Whipple,K.X. and Fletcher,J.K.(2008): Feedbacks among climate, erosion, and tectonics in a critical wedge orogen. American Journal of Science, 308, 815-842.

『臨界ウェッジ造山作用における気候と浸食と構造運動間のフィードバック』


Abstract
 The interactions among climate, erosion, and tectonics have long been of interest to geologists, but have not yet been united into a single theoretical framework. In this study, representations of orographic precipitation and fluvial erosion are combined with the concept of a critical wedge orogen. The idealized framework captures the basic system dynamics. It also allows for a formal analysis of the precipitation and tectonic interactions in terms of feedback factors and gains, and so permits a quantitative comparison of their relative strengths. The constraint of self-similar growth in a critical wedge orogen acts as a tectonic governor, whereby changes in orogen size are strongly damped. We determine that this negative tectonic feedback is stronger than the precipitation feedback, which may be negative or positive depending on whether precipitation increases or decreases with orogen size. For an extreme positive feedback unconstrained runaway growth is possible, ultimately leading to plateau formation. When orographic precipitation leads to a significant rain shadow, there is a strong partitioning of rock uplift rates that favors the wet, windward flank of the orogen. This flank also dominates the response of the whole orogen to changes in climate or tectonic forcing, except in the case where a large fraction of the eroded material is recycled into the wedge. Finally, it is demonstrated that the response time of the orogen depends on the feedbacks, and is proportional to the gain of the system.』

1. Introduction
2. Feedback basics
 2.1. A precipitation feedback
 2.2. Definitions of grains and feedback factors
3. Orographic precipitation
 3.1. Precipitation as a function of orogen size
 3.2. Discussion of precipitation model
4. The case of a one-sided critical wedge orogen
 4.1. Results of coupling one-sided critical wedge orogen to orographic precipitation model
 4.2. Runaway growth
5. Response of rock uplift rates to the precipitation feedback
6. The case of a two-sided critical wedge orogen
 6.1. Partitioning of rock uplift rates
 6.2. Response of two-sided orogen to a climate feedback
 6.3. The effect of sediment recycling
7. The relative strength of the tectonic and precipitation feedbacks
8. The connection between feedback strength and the orogen response time
9. Summary
10. Discussion
Acknowledgments
Appendix A Feedback analysis for two-sided critical wedge
References


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