Landscape response to hydroclimate variability shown by the post-Bonneville Flood (ca. 18 ka) fluvial-geomorphic history of the middle Snake River, Idaho, USA
Landscape response to hydroclimate variability shown by the post-Bonneville Flood (ca. 18 ka) fluvial-geomorphic history of the middle Snake River, Idaho, USA
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DOI：
10.1017/qua.2022.60
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发表时间：
2022-12
影响因子：
2.3
通讯作者：
S. Bacon;T. F. Bullard;Vaughn R. Kimball;C. Neudorf;S. Baker
中科院分区：
文献类型：
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作者：
S. Bacon;T. F. Bullard;Vaughn R. Kimball;C. Neudorf;S. Baker
摘要爱达荷州班克罗夫特斯普林斯蛇河中游的河流地貌和地层，为自约1950年邦纳维尔洪水以来蛇河的多次加积和下切提供了证据。18 ka。一套七阶地，范围从20-1米以上的现代岸高记录多个切割和填充周期在最近的更新世和全新世响应当地基准面控制，沉积物供应的变化，和水文气候变化。放射性碳和发光测年表明，河流加积的年龄通常与新仙女木时期（约1000年）开始时沉积物供应增加和水文气候可能更加湿润相一致。13.2 ka），冰川消退和新仙女木stadial（ca. 11.3 ka），早全新世冷却（ca. 8.8 ka），and Neoglacial（ca. 4.5，2.9，1.1 ka）。六个干预期的切口和通道的稳定性也可能反映了减少沉积物供应，干燥的水文气候，或两者兼而有之。阶地年表可以与各种地方和区域的古气候代理记录，以及对应的大陆和全球尺度的快速气候变化在全新世时期。河流记录显示了大型河流系统对水文气候变化的地貌响应和敏感性，这对推断该地区的古环境条件具有重要意义。
Abstract The fluvial geomorphology and stratigraphy on the middle Snake River at Bancroft Springs, Idaho, provide evidence for numerous episodes of Snake River aggradation and incision since the Bonneville Flood at ca. 18 ka. A suite of seven terraces ranging from 20–1 m above modern bankfull elevation records multiple cut-and-fill cycles during the latest Pleistocene and Holocene in response to local base-level controls, variations in sediment supply, and hydroclimate change. Radiocarbon and luminescence dating show that the ages of fluvial aggradation generally coincide with increased sediment supply and likely wetter hydroclimate during onset of the Younger Dryas stadial (ca. 13.2 ka), deglaciation and termination of the Younger Dryas stadial (ca. 11.3 ka), Early Holocene cooling (ca. 8.8 ka), and Neoglacial (ca. 4.5, 2.9, 1.1 ka). Six intervening periods of incision and channel stability may also reflect either reduced sediment supply, drier hydroclimate, or both. The terrace chronology can be correlated to a variety of local and regional paleoclimate proxy records and corresponds well with periods of continental- and global-scale rapid climate change during the Holocene. The fluvial record demonstrates the geomorphic response and sensitivity of large river systems to changes in hydroclimate variability, which has important implications for inferring paleoenvironmental conditions in the region.