近日，美国华盛顿大学Joel Gombiner和加拿大温哥华岛大学Jerome-Etienne Lesemann，合作报道了美国奥卡诺根叶形隧道河道和冰下洪水流入摩西深谷。相关论文于2024年3月26日发表在《地质学》杂志上。

来自密苏拉冰川湖的突发性洪水在很大程度上解释了，美国西部华盛顿地区度发育的玄武质河道系统——槽型的火山地带的侵蚀。然而，由于密苏拉的地形与洪水路线的地形隔离，研究人员很难解释密苏拉洪水进入摩西深谷的路径。

为了阐明洪水进入进入摩西深谷的路径，研究人员绘制了准确标出连接摩西深谷的放射状网状网络通道。河道主要由在玄武岩中侵蚀的类似深谷状地貌组成。河道爬上逆坡并跨越分水岭，河道网络被蛇丘和退潮的冰碛所覆盖。这些河道的几何形状和冰川地貌组合暗示了这是一个隧道河道网络。大的河道尺寸和网络吻合暗示了冰下洪水的形成。这个网络与摩西深谷相连，有足够的横截面积来输送特大洪水。研究结果强调，除了可能分流的密苏拉洪水，冰下洪水可能是摩西深谷融水的重要来源。

附：英文原文

Title: Okanogan lobe tunnel channels and subglacial floods into Moses Coulee, Channeled Scabland, northwestern United States

Author: Joel Gombiner, Jerome-Etienne Lesemann

Issue&Volume: 2024-03-26

Abstract: Outburst floods from glacial Lake Missoula largely explain erosion of the Channeled Scabland, a system of overfit, basaltic channels in Washington, northwestern United States. However, it is challenging to explain Missoula flood routing into Moses Coulee due to its topographic isolation from flood routes. To clarify flood pathways into Moses Coulee, we mapped channels that delineate a radial-anastomosing network connecting to Moses Coulee. Channels consist of coulee-like features eroded mainly in basalt. Channels climb adverse slopes and cross divides, and the network is draped with eskers and recessional moraines. These channel geometries and glacial landform associations suggest a tunnel channel network. Large channel dimensions and network anastomosis indicate formation in subglacial floods. The network connects to Moses Coulee with sufficient cross-sectional area to convey megafloods, hinting that subglacial floods may have been a significant source of Moses Coulee meltwater, in addition to possible diverted Missoula floods.

DOI: 10.1130/G52005.1

Source: https://pubs.geoscienceworld.org/gsa/geology/article-abstract/doi/10.1130/G52005.1/637038/Okanogan-lobe-tunnel-channels-and-subglacialredirectedFrom=fulltext