Chemical erosion is of wide interest due to its influence on topography, nutrient supply to streams and soils, sediment composition, and Earth's climate. While controls on chemical erosion rate have been studied extensively in steady‐state models, few studies have explored the controls on chemical erosion rate during transient responses to external perturbations. Here we develop a numerical model for the coevolution of soil‐mantled topography, soil thickness, and soil mineralogy, and we use it to simulate responses to step changes in rates of rock uplift, soil production, soil transport, and mineral dissolution. These simulations suggest that tectonic and climatic perturbations can generate responses in soil chemical erosion rate that differ in speed, magnitude, and spatial pattern and that climatic and tectonic perturbations may impart distinct signatures on hillslope mass fluxes, soil chemistry, and sediment composition. The response time of chemical erosion rate is dominantly controlled by hillslope length and is secondarily modulated by rates of rock uplift, soil production, transport, and mineral dissolution. This strong dependence on drainage density implies that a landscape's chemical erosion response should depend on the relative efficiencies of river incision and soil transport and thus may be mediated by climatic and biological factors. The simulations further suggest that the timescale of the hillslope response may be long relative to that of river channel profiles, implying that chemical erosion response times may be limited more by the sluggishness of the hillslopes than by the rate of signal propagation through river channel profiles.

中文翻译：

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化学侵蚀率对构造和气候变化的响应中坡度尺度的重要性

由于化学侵蚀会影响地形，影响河流和土壤的养分供应，沉积物成分以及地球气候，因此受到广泛关注。虽然在稳态模型中已经广泛研究了化学腐蚀速率的控制，但是很少有研究探索在对外部扰动的瞬态响应期间化学腐蚀速率的控制。在这里，我们建立了一个土壤覆盖地形，土壤厚度和土壤矿物学共同演化的数值模型，并用它来模拟对岩石抬升速率，土壤产量，土壤运输和矿物溶解速率阶跃变化的响应。这些模拟结果表明，构造和气候扰动可对土壤化学侵蚀速率产生不同的响应，其速度，幅度，和空间格局，以及气候和构造扰动可能在斜坡质量通量，土壤化学和沉积物组成方面赋予鲜明的特征。化学侵蚀速率的响应时间主要由山坡长度控制，其次由岩石隆起，土壤生产，运输和矿物溶解的速率调节。这种对排水密度的强烈依赖性意味着景观的化学侵蚀响应应取决于河流切口和土壤运输的相对效率，因此可能受气候和生物因素的影响。模拟进一步表明，山坡响应的时间尺度可能比河道剖面的时间尺度长，