Differences in channel and hillslope geometry record a migrating uplift wave at the Mendocino triple junction, California, USA
Differences in channel and hillslope geometry record a migrating uplift wave at the Mendocino triple junction, California, USA
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DOI：
10.1130/g46939.1
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发表时间：
2019-10
期刊：
影响因子：
5.8
通讯作者：
F. Clubb;S. Mudd;M. Hurst;S. Grieve
中科院分区：
文献类型：
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作者：
F. Clubb;S. Mudd;M. Hurst;S. Grieve
构造板块的运动，以及由此产生的陆地表面高程的变化，已被证明对景观形态有着根本性的影响。上升速率的变化可以驱动河流通道的响应，然后驱动山坡的变化。由于山坡的反应在不同的时间尺度上比河流的渠道，调查几何形状的渠道和山坡一致提供了新的机会，研究如何隆起率可能随着时间的推移而变化。在这里，我们执行耦合地形分析的渠道和山坡几何形状跨越一系列的集水区在门多西诺三重结（MTJ）在北方加州，美国。这些集水区的特点是从北到南的抬升速率有数量级的差异。我们发现，无量纲的山坡起伏密切配合整个地区的隆起信号，并与通道陡度呈正相关。此外，山坡起伏的不确定性范围低于通道陡度，这表明它可能是一个更可靠的记录在MTJ地区的隆起。我们发现，山顶曲率滞后于救济在其响应隆起，这反过来又滞后于通道响应。这些综合指标显示了MTJ的北移和相应的隆起场，仅从地形数据。
Tectonic plate motion, and the resulting change in land surface elevation, has been shown to have a fundamental impact on landscape morphology. Changes to uplift rates can drive a response in fluvial channels, which then drives changes to hillslopes. Because hillslopes respond on different time scales than fluvial channels, investigating the geometry of channels and hillslopes in concert provides novel opportunities to examine how uplift rates may have changed through time. Here we perform coupled topographic analysis of channel and hillslope geometry across a series of catchments at the Mendocino triple junction (MTJ) in northern California, USA. These catchments are characterized by an order-of-magnitude difference in uplift rate from north to south. We find that dimensionless hillslope relief closely matches the uplift signal across the area and is positively correlated with channel steepness. Furthermore, the range of uncertainty in hillslope relief is lower than that of channel steepness, suggesting that it may be a more reliable recorder of uplift in the MTJ region. We find that hilltop curvature lags behind relief in its response to uplift, which in turn lags behind channel response. These combined metrics show the northward migration of the MTJ and the corresponding uplift field from topographic data alone.