A lobe of the late Wisconsin Laurentide Ice Sheet advanced from central Alberta, southeastward into Montana and southwestern Saskatchewan. It left the Cypress Hills and Boundary Plateau undisturbed. As the glacier crossed the present day Milk River valley in southern Alberta, it was split into two lobes by the Sweetgrass Hills, which became an island in the glacier. The western lobe or Shelby lobe, moved southward to the Missouri River, near Great Falls, Montana. The Havre lobe, east of the Sweetgrass Hills, moved in two directions. The Lorna sublobe, advanced over the Missouri River to north of the Highwood Mountains. The Malta sublobe expanded southeastward along the present-day Milk River, between the Boundary Plateau and the Little Rocky Mountains in the region of the Musselshell River.[2]
References
↑ Physiography and Glacial Geology of Eastern Montana and Adjacent Areas; William C. Alden; United States Government Printing Office: Washington, D.C.; 1932
1 2 Geologic Framework and Glaciation of the Central Area, 1-1-2006; Christopher L. Hill; Boise State University, Boise, Idaho; 2006
Bibliography
Alden, W. C., 1958, Physiography And Glacial Geology Of Eastern Montana And Adjacent Areas, U. S. Geological Survey Professional Paper 174.
Colton, R. B., Lemke, R. W., and Lindvall, R. M., 1961, Glacial map of Montana East of the Rocky Mountains, U. S. Geological Survey Miscellaneous Geological Investigations Map I-327.
Howard, A. D., 1958, Drainage Evolution In Northeastern Montana and Northwestern North Dakota, Bulletin of the Geological Society of America, v69, 575–588.
Lemke, R. W., Laird, W. M., Tipton, M. J., and Lindvall, R. M., 1965, Quaternary Geology Of Northern Great Plains, in Wright, H. E., Jr., and Frey, D. G., Eds, The Quaternary of the United States, Princeton University Press, Princeton, NJ.
Lindvall, R. M., 1962, Geology Of The Eagle Buttes Quadrangle, Chouteau County, Montana, U. S. Geological Survey Miscellaneous Geological Investigations Map I-349.
Thornbury, W. D., 1965, Regional Geomorphology Of The United States, John Wiley & Sons, Inc., New York.
Trimble, D. E., 1980, The Geologic Story Of The Great Plains, Geological Survey Bulletin 1493.
Wayne, W. J., Aber, J. S., Agard, S. S., Bergantino, R. N., Bluemle, J. P., Coates, D. A., Cooley, M. E., Madole, R. F., Martin, J. E., Mears, B., Jr., Morrison, R. B., and Sutherland, W. M., 1991, Quaternary Geology Of The Northern Great Plains, in The Geology of North America, Vol K-2, Quaternary Nonglacial Geology: Conterminous U. S., The Geological Society of America.
This page is based on this Wikipedia article Text is available under the CC BY-SA 4.0 license; additional terms may apply. Images, videos and audio are available under their respective licenses.
