Outburst flood origin of the Central Kalamazoo River Valley, Michigan, USA
Outburst flood origin of the Central Kalamazoo River Valley, Michigan, USA
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美国密歇根州卡拉马祖河谷中部爆发洪水的根源
DOI：
10.1016/j.quascirev.2005.03.016
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发表时间：
2005
影响因子：
4
通讯作者：
B. Bird
中科院分区：
文献类型：
--
作者：
A. Kozlowski;A. Kehew;B. Bird
地貌证据和钻孔中的地层信息表明，密歇根州西南部超大的中央卡拉马祖河谷(CKRV)是由劳伦蒂德冰盖萨吉诺小叶下的冰下渠道爆发的灾难性洪水造成的。CKRV位于一个由密歇根湖、萨吉诺和休伦-伊利湾形成的凹陷中，是一条超过2公里宽、超过50米深的深深切割的海沟。CKRV的路线沿着一条不规则的流动路线，将密歇根湖的卡拉马祖冰河一分为二。海峡入海口附近的侵蚀阶地表明，在向西的萨吉诺暴发之前，密歇根湖瓣融水向东排干。在山谷形成之前，密歇根湖已经向西后退，至少退到了莫雷恩湖的边界。由于没有密歇根湖小叶来阻碍水流，CKRV的排水继续向西南方向流动，直到排入密歇根州圣约瑟夫附近的冰川湖芝加哥。这次暴发源于萨吉诺隧道渠道系统，该系统显示了凸起的流动轮廓，并包含ESKER。融水排水从冰下到冰缘和冰期环境过渡。在爆发所代表的间隔期间，萨吉诺叶似乎处于相对静止的位置。
Geomorphic evidence and stratigraphic information from boreholes suggest that the oversized Central Kalamazoo River Valley (CKRV) in southwest Michigan resulted from a catastrophic outburst flood emanating from subglacial channels under the Saginaw lobe of the Laurentide Ice Sheet. The CKRV occurs as a deeply incised trench over 2km wide and in excess of 50m deep situated in a reentrant formed by the Lake Michigan, Saginaw and Huron-Erie lobes. The course of the CKRV follows an irregular flow path that bisects the Kalamazoo Moraine of the Lake Michigan lobe. Erosional terraces near the mouth of the channel indicate that Lake Michigan lobe meltwater drained eastward prior to the westward Saginaw outburst. Prior to valley formation the Lake Michigan lobe had retreated westward to at least the Lake Border Moraine. With the Lake Michigan lobe absent to impede flow, drainage from the CKRV proceeded southwesterly until draining into glacial Lake Chicago near St. Joseph, Michigan. The outburst originated from a system of Saginaw tunnel channels that display convex-up flow profiles and contain eskers. Meltwater drainage transitioned from subglacial-to-ice marginal and proglacial environments. During the interval represented by the outburst, the Saginaw Lobe appears to have been in a relatively stationary position.