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 |
Carboniferous--
Mississippian Series |
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. |
-glacial area
-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.