Spatial and temporal variations in denudation of the Wasatch Mountains, Utah, USA
Spatial and temporal variations in denudation of the Wasatch Mountains, Utah, USA
复制标题
美国犹他州瓦萨奇山脉剥蚀的时空变化
作者：
G. Stock;K. Frankel;T. Ehlers;M. Schaller;Stephanie M. Briggs;R. Finkel
我们评估剥蚀的中北部的瓦萨奇山脉，犹他州，通过确定流域范围内的剥蚀率与10 Be浓度在冲积沉积物和比较这些速率与以前公布的数据岩石隆起和折返的范围。排干山脉前缘的集水区的剥蚀率变化相对较小（0.07-0.17毫米/年），而山脉核心地带较陡（平均山坡坡度>30°）的集水区的剥蚀率变化较大（0.17-0.79毫米/年）。我们属性的范围内的阈值梯度的山坡滑坡的核心流域范围内的剥蚀较大的空间变化，更快的剥蚀在这一地区可能意味着晚更新世冰川景观调整。所有集水区的平均剥蚀率（0.2毫米/年）一般是一致的长期折返率来自热年代计和短期垂直断层位移率，这表明中北部的Wasatch的剥蚀已经大致稳定，或略有下降，在过去的5百万年。虽然10 Be为基础的流域范围内的剥蚀率是敏感的局部地貌过程和事件，总体而言，他们似乎反映了更大的构造力量，驱动剥蚀的瓦萨奇山脉在较长的时间尺度。
We evaluate spatial and temporal variations in denudation of the north-central Wasatch Mountains, Utah, by determining catchment-wide denudation rates with 10 Be concentrations in alluvial sediment and comparing these rates with previously published data on rock uplift and exhumation of the range. Catchments draining the range front show relatively little variation in denudation rate (0.07–0.17 mm/yr), while steeper (mean hillslope gradient >30°) catchments in the core of the range show larger variation (0.17–0.79 mm/yr). We attribute the larger spatial variation in catchment-wide denudation in the core of the range to landsliding of hillslopes at threshold gradients; faster denudation in this region may signify landscape adjustment to late Pleistocene glaciations. The mean denudation rate for all catchments (0.2 mm/yr) is generally consistent with longer-term exhumation rates derived from thermochronometers and with shorter-term vertical fault displacement rates, suggesting that denudation of the north-central Wasatch has been roughly steady, or decreasing slightly, over the past 5 m.y. Although 10 Be-based catchment-wide denudation rates are sensitive to localized geomorphic processes and events, overall, they appear to refl ect the larger tectonic forces that have driven denudation of the Wasatch Mountains over longer time scales.