Riverine measurements of sediment and solute transport give empirical basin-scale estimates of bed-load, suspended-sediment, and silicate-solute fluxes for 100,000 km2 of northwestern California and western Oregon. This spatially explicit sediment budget shows the multifaceted control of geology and physiography on the rates and processes of fluvial denudation. Bed-load transport is greatest for steep basins, particularly in areas underlain by the accreted Klamath terrane. Bed-load flux commonly decreases downstream as clasts convert to suspended load by breakage and attrition, particularly for softer rock types. Suspended load correlates strongly with lithology, basin slope, precipitation, and wildfire disturbance. It is highest in steep regions of soft rocks, and our estimates suggest that much of the suspended load is derived from bed-load comminution. Dissolution, measured by basin-scale silicate-solute yield, constitutes a third of regional landscape denudation. Solute yield correlates with precipitation and is proportionally greatest in low-gradient and wet basins and for high parts of the Cascade Range, where undissected Quaternary volcanic rocks soak in 2–3 m of annual precipitation. Combined, these estimates provide basin-scale erosion rates ranging from ∼50 t · km−2 · yr−1 (approximately equivalent to 0.02 mm · yr−1) for low-gradient basins such as the Willamette River to ~500 t · km−2 · yr−1 (∼0.2 mm · yr−1) for steep coastal drainages. The denudation rates determined here from modern measurements are less than those estimated by longer-term geologic assessments, suggesting episodic disturbances such as fire, flood, seismic shaking, and climate change significantly add to long-term landscape denudation.

中文翻译：

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侵蚀卡斯卡迪亚——俄勒冈州西部和加利福尼亚州西北部的沉积物和溶质迁移和景观剥蚀

对沉积物和溶质迁移的河流测量给出了对加利福尼亚西北部和俄勒冈州西部 100,000 平方公里的床载、悬浮沉积物和硅酸盐-溶质通量的经验性盆地尺度估计。这种空间明确的沉积物收支显示了地质和地理学对河流剥蚀速率和过程的多方面控制。陡峭盆地的床载运输最大，特别是在克拉马斯地体下面的地区。随着碎屑通过破碎和磨损转变为悬浮载荷，床载通量通常会降低下游，特别是对于较软的岩石类型。悬浮荷载与岩性、盆地坡度、降水和野火扰动密切相关。它在软岩陡峭地区最高，我们的估计表明，大部分悬浮负载来自床负载粉碎。以盆地尺度硅酸盐-溶质产量衡量的溶解作用构成了区域景观剥蚀的三分之一。溶质产量与降水量相关，并且在低梯度和潮湿盆地以及喀斯喀特山脉的高处比例最大，在那里未解剖的第四纪火山岩吸收了 2-3 m 的年降水量。综合起来，这些估计提供的流域尺度侵蚀速率范围从约 50 t · km−2 · yr−1（约等于 0.02 mm · yr−1）（如威拉米特河）到约 500 t · km 的低梯度流域-2 · yr−1 (∼0.2 mm · yr−1) 对于陡峭的沿海排水系统。这里根据现代测量确定的剥蚀率低于长期地质评估估计的剥蚀率，