You are not currently logged in.
Access JSTOR through your library or other institution:
If You Use a Screen ReaderThis content is available through Read Online (Free) program, which relies on page scans. Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.
The Influence of Geologic Structure on the Drainage Pattern in Northeastern Minnesota
Karl ver Steeg
The Journal of Geology
Vol. 55, No. 4 (Jul., 1947), pp. 353-361
Published by: The University of Chicago Press
Stable URL: http://www.jstor.org/stable/30058852
Page Count: 12
You can always find the topics here!Topics: Slates, Glacial lakes, Ridges, Valleys, Gabbro, Granite, Highlands, Glacial soils, Drainage patterns, Streams
Were these topics helpful?See somethings inaccurate? Let us know!
Select the topics that are inaccurate.
Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.
Preview not available
The region is especially interesting from the standpoint of geomorphology. Erosion of monoclinal structure of the Animikie and Keweenawan formations has developed ridges with an asymmetrical profile, known as "sawtooth mountains." The ridge and valley topography in the area underlain by the Rove slate and associated intrusives (dikes, and sills) resembles that of the folded Appalachians. The preglacial drainage pattern was trellised. The Duluth gabbro is banded; those zones composed of minerals less resistant to weathering and erosive agencies underlie the valleys, and the more resistant rocks, such as the "red rock," make up the ridges. The lakes located on the Saganaga granite are irregular in outline and are not oriented in any particular direction. The Pleistocene ice sheets produced noteworthy changes in the drainage lines. Numerous glacial lakes now occupy depressions which show striking east-west alignment. Many of the streams are new or have been forced to find new channels. Waterfalls and rapids and postglacial gorges are common.
The Journal of Geology © 1947 The University of Chicago Press