TheMichigan Basin is ageologic basin centered on theLower Peninsula of theU.S. state ofMichigan. The feature is represented by a nearly circular pattern of geologicsedimentarystrata in the area with a nearly uniform structuraldip toward the center of the peninsula.
The basin is centered inGladwin County where thePrecambrianbasement rocks are 16,000 feet (4,900 m) deep. Around the margins, such as underMackinaw City, Michigan, the Precambrian surface is around 4,000 feet (1,200 m) below the surface. This 4,000-foot (1,200 m) contour on the basement surface clips the northern part of the Lower Peninsula and continues underLake Michigan along the west. It crosses the southern counties of Michigan and continues to the north beneathLake Huron.
On the north in theCanadian Shield, which includes the western part of Michigan'sUpper Peninsula, Precambrian rocks are exposed at the surface. The eastern margins ofWisconsin alongGreen Bay are along the margins of the basin, while Precambrian rocks crop out to the west in central Wisconsin. The northeastern margin ofIllinois aroundChicago is on the southwestern margin of the basin. The southeast-strikingKankakee Arch continuation of theCincinnati Arch forms the southwest boundary of the basin underlying northeastern Illinois and northernIndiana. To the east, the Findlay Arch forms the southeast margin of the basin as it strikes to the northeast across northwesternOhio, under the bed ofLake Erie and on as the Algonquin Arch through the southwestern prong ofOntario. The Wisconsin Arch forms the western boundary of the basin.
Therocks of the basin includeCambrian-Ordoviciansandstones andcarbonate rocks around the margins and at depth.Silurian-Devoniandolomites andlimestones withCarboniferous (Mississippian andPennsylvanian) strata are located basinward or above filling in the center. A veneer ofJurassic sediments is found in the center of the basin at the surface.
The basin appears to have subsided concurrently with sediment infilling. These sediments were found to be mainly shallow-water sediments, many of which are richly fossiliferous. The location was on a geologically passive portion of crust. The development of the basin and the surrounding arches were likely affected by thetectonic activity of the long-termAppalachian orogeny several hundred miles to the south and east.
Within the Precambrian rocks beneath and just west of the center of the basin lies a generally north to northwest trending linear feature that appears to be an ancientrift in the Earth'scrust. This rift appears to be contiguous with the rift zone underLake Superior. This, theMidcontinent Rift System, turns west under Lake Superior and then southwest through southernMinnesota, central and westernIowa and southeasternNebraska and into easternKansas.
Some minerals that have been mined from rocks in the basin includehalite andgypsum.Halite (rock salt) occurs in beds of theSalina Formation (Silurian) and theDetroit River Group (Devonian). TheDetroit salt mine has mined rock salt from beneath theDetroit metropolitan area since 1906.[2]Brine recovered from wells in the Michigan basin has been used as a commercial source ofpotassium salts,bromine,iodine,calcium chloride, andmagnesium salts.[3]
| Michigan Basin | |
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| Country | United States |
| Region | Northern Michigan |
| Location | Northern Michigan |
| Offshore/onshore | Onshore |
| Operators | Chevron Corporation |
| Production | |
| Producing formations | Michigan Basin |
The rocks of the Michigan Basin are the source of commercial quantities ofpetroleum. The most actively drilled-for source ofnatural gas in recent years has beenshale gas from theDevonianAntrim Shale in the northern part of the basin.
The Michigan basin extends into Ontario, Canada, where oil and gas regulators are studying its potential. It is considered to be one of "America's most promising oil and gas plays."[4] In May 2010, a Michigan public land auction attracted the attention of the largest North American natural gas corporations, such as Encana (nowOvintiv) andChesapeake Energy. From 2008 through 2010, Encana accumulated a "large land position" (250,000 net acres)[4] in a shale gas play in Michigan's Middle Ordovician Collingwood shale. Encana focused activities inCheboygan,Kalkaska, andMissaukee counties in Michigan's northern Lower Peninsula.[5] Natural gas is produced from both Utica and Collingwood shale (called Utica Collingwood). Collingwood is a shaly limestone about 40 feet thick that lies just above the Ordovician Trenton formation. Utica shale overlies the Collingwood.[5]
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