Editing Lake Erie (section)

==Geology==
Lake Erie was carved out by [[glacier]] ice and went through many phases before its current form that is less than 4,000 years old, which is a short span in geological terms.<ref name="k012">{{cite book | last=Robbins | first=P. | title=Encyclopedia of Environment and Society: FIVE-VOLUME SET | publisher=SAGE Publications | series=Gale virtual reference library | year=2007 | isbn=978-1-4522-6558-2 | url=https://books.google.com/books?id=9JvtBQAAQBAJ&pg=PA604 | access-date=2024-11-29 | page=604}}</ref> Before this, the land on which the lake now sits went through several complex stages. A large lowland basin formed over two million years ago as a result of an eastern flowing river that existed well before the [[Quaternary glaciation|Pleistocene ice ages]]. This ancient drainage system was destroyed by the first major glacier in the area, while it deepened and enlarged the lowland areas, allowing water to settle and form a lake. The glaciers were able to carve away more land on the eastern side of the lowland because the bedrock is made of [[shale]] which is softer than the carbonate rocks of [[Dolomite (mineral)|dolomite]] and [[limestone]] on the western side. Thus, the eastern and central basins of the modern lake are much deeper than the western basin, which averages only {{convert|25|ft|m}} deep and is rich in nutrients and fish.<ref name=twsOhioStateUniv/> Lake Erie is the shallowest of the Great Lakes because the ice was relatively thin and lacked erosion power when it reached that far south, according to one view.

[[File:Lake Warren Fig 15.JPG|thumb|Map of Lake Warren in the Lake Huron and Lake Erie Basins]]
As many as three glaciers advanced and retreated over the land, causing temporary lakes to form in the time periods in between each of them (see: [[Lake Whittlesey]], [[Lake Maumee]] and [[Lake Arkona]]). Because each lake had a different volume of water, their shorelines rested at differing elevations. The last lake to form, [[Lake Warren]], existed between about 13,000 and 12,000 years ago. It was deeper than the current Lake Erie, and its shoreline existed about {{convert|8|mi|km|spell=in}} inland from the modern one. [[Early Lake Erie]] went through many phases with its ancient sand dunes visible in the [[Oak Openings Region]] in [[Northwest Ohio]]. There, the sandy dry lake bed soil was not sufficient to support large trees with the exception of a few species of oaks, forming a rare [[oak savanna]].<ref>{{cite web|url=http://www.ohiodnr.com/geosurvey/lakeerie/lefact1/tabid/7829/Default.aspx|title=Hansen, Michael C. "The History of Lake Erie"|publisher=Ohiodnr.com|access-date=December 10, 2012|archive-date=November 24, 2011|archive-url=https://web.archive.org/web/20111124080806/http://www.ohiodnr.com/geosurvey/lakeerie/lefact1/tabid/7829/Default.aspx|url-status=live}}</ref>