10Be analysis of amalgamated talus pebbles to investigate alpine erosion, Garnet Canyon, Teton Range, Wyoming
10Be analysis of amalgamated talus pebbles to investigate alpine erosion, Garnet Canyon, Teton Range, Wyoming
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10Be 分析合并的距骨卵石以调查高山侵蚀，石榴石峡谷，提顿山脉，怀俄明州
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发表时间：
2017
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通讯作者：
Meredith L. Strow
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作者：
L. Tranel;Meredith L. Strow
冰川和随后的大规模浪费事件创造了令人印象深刻的山地景观;然而，定义这些美丽景观的崎岖性也使得监测实地侵蚀具有挑战性。其结果是，高山景观的侵蚀的空间格局和速度研究不足。现场位置陡峭，偏远和山坡过程，包括落石，雪崩和山体滑坡，是随机的，难以直接测量。本研究使用岩屑扇沉积物，以加深我们对美国怀俄明州提顿山脉石榴石峡谷高山环境中单个扇沉积和集水区平均侵蚀过程的理解。我们测量了宇宙成因的10Be浓度从基岩和岩屑沉积物进行比较，以体积估计的侵蚀速率，地衣生长和岩屑表面风化。从岩屑沉积物的混合卵石含有较低的10Be浓度比任何基岩表面或流沉积物。年轻的岩屑堆表面暴露年龄均小于11 ka，反映了冰川退缩后长期持续的落石活动的重要性。只有一个岩屑扇对应于已知的地震事件。岩屑沉积物流系统的贡献; 10Be浓度低于汞齐岩屑卵石比汞齐流砂。地衣覆盖，侵蚀速率的体积估计，和10Be浓度表现出类似的空间趋势，反映了迁移的活动落石到更高的海拔和验证的适用性10Be浓度量化堆积物表面年龄。石榴石峡谷内的不同表面上的不同10 Be浓度表明，未来的工作与混合样品的堆积物可以有助于调查高山景观的景观演变。
Glaciers and subsequent mass wasting events create impressive mountain landscapes; however, the ruggedness that defines these beautiful landscapes also makes it challenging to monitor erosion in the field. The result is that spatial patterns and rates of erosion in alpine landscapes are understudied. Field locations are steep and remote and hillslope processes, including rockfalls, avalanches, and landslides, are stochastic and difficult to measure directly. This study uses talus fan sediments to deepen our understanding of individual fan deposition and catchment averaged erosion processes in the alpine setting of Garnet Canyon in the Teton Range, Wyoming, USA. We measured cosmogenic 10Be concentrations from bedrock and talus deposits to compare them to volumetric estimates of erosion rates, lichen growth, and surface weathering on talus surfaces. Amalgamated pebbles from the talus deposits contained lower 10Be concentrations than any bedrock surfaces or stream sediments. The young talus surface exposure ages are all younger than 11 ka, reflecting the importance of continued rockfall activity long after glacial retreat. Only one talus fan corresponded to known seismic events. Talus deposits contribute sediments to stream systems; 10Be concentrations were lower in amalgamated talus pebbles than in amalgamated stream sands. Lichen cover, volumetric estimates of erosion rates, and 10Be concentrations showed similar spatial trends reflecting the migration of active rockfalls to higher elevations and validating the applicability of 10Be concentrations to quantify talus surface ages. Distinct 10Be concentrations on various surfaces within Garnet Canyon indicate that future work with amalgamated samples from talus deposits can contribute to investigations about landscape evolution in alpine landscapes.