School of Geosciences, University of Edinburgh, Drummond Street, Edinburgh EH8 9XP, UK.
Science. 2013 Aug 23;341(6148):868-71. doi: 10.1126/science.1241791.
Earth's surface archives the combined history of tectonics and erosion, which tend to roughen landscapes, and sediment transport and deposition, which smooth them. We analyzed hillslope morphology in the tectonically active Dragon's Back Pressure Ridge in California, United States, to assess whether tectonic uplift history can be reconstructed using measurable attributes of hillslope features within landscapes. Hilltop curvature and hillslope relief mirror measured rates of vertical displacement caused by tectonic forcing, and their relationships are consistent with those expected when idealizing hillslope transport as a nonlinear diffusion process. Hilltop curvature lags behind relief in its response to changing erosion rates, allowing growing landscapes to be distinguished from decaying landscapes. Numerical modeling demonstrates that hillslope morphology may be used to infer changes in tectonic rates.
地球表面记录了构造和侵蚀的综合历史,这些过程往往会使地貌变得崎岖不平,而泥沙的搬运和沉积则会使地貌变得平坦。我们分析了美国加利福尼亚州构造活跃的龙脊压力脊的山坡形态,以评估是否可以利用景观内山坡特征的可测量属性来重建构造抬升历史。山顶曲率和山坡起伏反映了构造力引起的垂直位移的测量速率,它们之间的关系与将山坡输运理想化作为非线性扩散过程时的预期一致。在响应不断变化的侵蚀速率时,山顶曲率滞后于地形起伏,从而可以区分正在生长的景观和正在衰减的景观。数值模拟表明,山坡形态可用于推断构造速率的变化。