Editing Minnesota (section)

=== Geology ===

{{Main|Geology of Minnesota}}
{{See also|List of lakes in Minnesota|List of Minnesota rivers}}

[[File:StLouisRiver JayCooke.JPG|thumb|right|Tilted beds of the Middle [[Precambrian]] Thomson Formation in [[Jay Cooke State Park]]<ref name="MNGeog">{{cite book | last = Ojakangas | first = Richard W. |author2=Charles L. Matsch | others = Illus. Dan Breedy | title = Minnesota's Geology | year = 1982 | publisher = [[University of Minnesota Press]] | location= Minneapolis, Minnesota | isbn = 978-0-8166-0953-6}}</ref>]]

Minnesota has some of the earth's oldest rocks, [[gneiss]]es that are about 3.6{{spaces}}billion years old (80% as old as the planet).<ref name="MNGeog" /><ref name=autogenerated1>{{cite web | title = Geologic Time: Age of the Earth | publisher = United States Geological Survey | date = October 9, 1997 | url = http://pubs.usgs.gov/gip/geotime/age.html | access-date = April 9, 2008 | archive-url = https://web.archive.org/web/20051223072700/http://pubs.usgs.gov/gip/geotime/age.html | archive-date = December 23, 2005 | url-status = live }}</ref> About 2.7{{spaces}}billion years ago [[basalt]]ic [[lava]] poured out of cracks in the floor of the primordial [[ocean]]; the remains of this [[volcano|volcanic]] rock formed the [[Canadian Shield]] in northeast Minnesota.<ref name="MNGeog" /><ref name="Compass">{{cite book | last = Breining | first = Greg | title = Compass American Guides: Minnesota, 3rd Edition | edition = 3rd | publisher = [[Fodor's|Compass American Guides]] | date = December 2005 | isbn = 978-1-4000-1484-2 | url-access = registration | url = https://archive.org/details/minnesota0003brei }}</ref> The roots of these volcanic mountains and the action of [[Precambrian]] seas formed the [[Iron Range]] of northern Minnesota. Since a period of [[volcanism]] 1.1{{spaces}}billion years ago, Minnesota's geological activity has been more subdued, with no volcanism or mountain formation, but with repeated incursions of the sea, which left behind multiple strata of [[sedimentary rock]].<ref name="MNGeog" />

In [[Glacial history of Minnesota|more recent times]], massive ice sheets at least one kilometer thick ravaged the state's landscape and sculpted its terrain.<ref name="MNGeog" /> The [[Wisconsin glaciation]] left 12,000 years ago.<ref name="MNGeog" /> These glaciers covered all of Minnesota except the far southeast, an area characterized by steep hills and streams that cut into the [[bedrock]]. This area is known as the [[Coulee Region|Driftless Zone]] for its absence of [[drift (geology)|glacial drift]].<ref>{{cite web|title=Natural history – Minnesota's geology |publisher=Minnesota DNR |url=http://www.dnr.state.mn.us/snas/naturalhistory.html |year=2008 |access-date=April 9, 2008 |archive-url=https://web.archive.org/web/20061010202724/http://www.dnr.state.mn.us/snas/naturalhistory.html |archive-date=October 10, 2006 }}</ref> Much of the remainder of the state has 50 feet (15{{spaces}}m) or more of [[glacial till]] left behind as the last glaciers retreated. Gigantic [[Lake Agassiz]] formed in the northwest 13,000 years ago. Its flatbed now is the fertile [[Red River of the North|Red River]] valley, and its outflow, [[glacial River Warren]], carved the valley of the [[Minnesota River]] and the Upper Mississippi downstream from [[Fort Snelling]].<ref name="MNGeog" /> Minnesota is geologically quiet today; it experiences [[earthquake]]s infrequently, most of them minor.<ref>{{cite web|title=Table Showing Minnesota Earthquakes |publisher=University of Minnesota, Morris |url=http://www.mrs.umn.edu/earthquakes/MNeqchart.html |access-date=April 9, 2008 |archive-url=https://web.archive.org/web/20080327204634/http://www.mrs.umn.edu/earthquakes/MNeqchart.html |archive-date=March 27, 2008 }}</ref>
[[File:Palisade, Shovel Point (cropped).jpg|thumb|[[Palisade Head]] on [[Lake Superior]] was formed from a [[Precambrian]] [[rhyolitic]] [[lava]] flow.<ref name="MNGeog" />]]

The state's high point is [[Eagle Mountain (Minnesota)|Eagle Mountain]] at 2,301 feet (701{{spaces}}m), which is only {{convert|13|mi|km}} away from the low point of 601 feet (183{{spaces}}m) at the shore of Lake Superior.<ref name="Compass" /><ref>{{cite web | title = {{convert|118|km|0|abbr=on}} SW of Thunder Bay, Ontario, Canada | website = Topographic map | publisher = U.S.G.S via terraserver.microsoft.com | date = July 1, 1964 | url = http://msrmaps.com/map.aspx?t=2&s=16&lon=-90.56700164&lat=47.79184974&w=600&h=400&opt=0 | access-date = April 13, 2010 | archive-url = https://web.archive.org/web/20131009100944/http://msrmaps.com/map.aspx?t=2&s=16&lon=-90.56700164&lat=47.79184974&w=600&h=400&opt=0 | archive-date = October 9, 2013 | url-status = live }}</ref> Notwithstanding dramatic local differences in elevation, much of the state is a gently rolling [[peneplain]].<ref name="MNGeog" />

Two major [[drainage divide]]s meet in Minnesota's northeast in rural [[Hibbing, Minnesota|Hibbing]], forming a triple [[Drainage basin|watershed]]. [[Precipitation (meteorology)|Precipitation]] can follow the [[Mississippi River]] south to the [[Gulf of Mexico]], the [[Saint Lawrence Seaway]] east to the Atlantic Ocean, or the [[Canada Hudson Bay drainage|Hudson Bay watershed]] to the Arctic Ocean.<ref>{{cite web|title=Continental Divides in North Dakota and North America |publisher=National Atlas |date=October 2, 2007 |url=http://nationalatlas.gov/articles/geology/a_continentalDiv.html |access-date=April 9, 2008 |archive-url=https://web.archive.org/web/20080513163803/http://nationalatlas.gov/articles/geology/a_continentalDiv.html |archive-date=May 13, 2008 }}</ref>

The state's nickname "Land of 10,000 Lakes" is apt, as there are 11,842 [[Minnesota lakes]] over {{convert|10|acre|ha|0}} in size.<ref name="dnr">{{cite web | title = Lakes, rivers & wetlands | website = MN Facts | publisher = Minnesota DNR | year = 2008 | url = http://www.dnr.state.mn.us/faq/mnfacts/water.html | access-date = April 9, 2008 | archive-url = https://web.archive.org/web/20130629143248/http://www.dnr.state.mn.us/faq/mnfacts/water.html | archive-date = June 29, 2013 | url-status = live }}</ref> Minnesota's portion of Lake Superior is the largest at {{convert|962,700|acre|ha km2}} and deepest (at {{convert|1290|ft|m|abbr=on}}) body of water in the state.<ref name="dnr" /> Minnesota has 6,564 natural rivers and streams that cumulatively flow for {{convert|69,000|mi|km}}.<ref name="dnr" /> The Mississippi River begins its journey from its [[headwaters]] at [[Lake Itasca]] and crosses the Iowa border {{convert|680|mi|km}} downstream.<ref name="dnr" /> It is joined by the [[Minnesota River]] at Fort Snelling, by the [[St. Croix River (Wisconsin-Minnesota)|St. Croix River]] near [[Hastings, Minnesota|Hastings]], by the [[Chippewa River (Wisconsin)|Chippewa River]] at [[Wabasha, MN|Wabasha]], and by many smaller streams. The Red River drains the northwest part of the state northward toward Canada's Hudson Bay. Approximately {{convert|10.6|e6acre|ha km2}} of wetlands are within Minnesota's borders, the most of any state outside Alaska.<ref name="weatheralmanac">{{cite book | last = Seeley | first = Mark W. | title = Minnesota Weather Almanac | publisher = [[Minnesota Historical Society]] press | year = 2006 | isbn = 978-0-87351-554-2 | url = https://archive.org/details/minnesotaweather0000seel }}</ref>