Geological History--Ann Arbor Public Library's Geologic Atlas of the U.S.
The Ann Arbor area geological make-up.
|System||Formation||Thickness||Character of Rocks|
|Marshall Sandstone||150+||Brown, gray and yellowish sandstone. Iron Concretions near bases. "Second" brine horizon|
|.||Cold Water Shale||670-960||Light colored, green, bluish, pinkish and gray shale's with siliceous layers and lenses of sandstone|
|.||(60)||Black, biluminous shale. May represent Sunbury shale|
|Berea Sandstone||65||Coarse gray sandstone. "Third" brine.|
-map shows that Ann Arbor is a glacial outwash area in the center of two moraines: Fort Wayne Moraine (terminal Moraine to the West) and Defiance Moraine Outer (terminal Moraine to the East).
-glacial outwash defined: gravel deposited by glacial drainage deposits of old southwestward Huron drainage. Qgoh and clay deposits in ponded water.