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Mineral Resources > Online Spatial Data > Geology > by state > Minnesota Geology

Geologic units in Martin county, Minnesota

Upper Cambrian, undivided (Late Cambrian) at surface, covers 6 % of this area

Upper Cambrian, undivided - Jordan Sandstone; dolomite, glauconite, and silty glauconite rocks of the St. Lawerence and Franconia Formation; Ironton and Galesville Sandstones; sandy and shaly rocks of the Eau Claire Formation; and the Mt. Simon Sandstone.

Lithology: dolostone (dolomite); sandstone; shale

Lower Ordovician rocks, undivided (Lower Ordovician) at surface, covers 1 % of this area

Lower Ordovician rocks, undivided - Shakopee and Oneota Formations of the Prairie du Chien Group in the Hollandale embayment of southeastern Minnesota. Unit consists dominantly of dolostone and dolomitic limestone. The Shakopee also contains intervals of quartz arenite, including a pronounced basal unit named the New Richmond Member

Lithology: dolostone (dolomite); limestone; sandstone

Middle Ordovician rocks, undivided (Middle Ordovician) at surface, covers 1 % of this area

Middle Ordovician rocks, undivided - Decorah Shale; limestone of the Platteville Formation; shaly rocks of the Glenwood Formation; and St. Peter Sandstone in the Hollandale embayment of southeastern Minnesota

Lithology: sandstone; limestone; shale

Sioux Quartzite (Early Proterozoic) at surface, covers 5 % of this area

Sioux Quartzite - Red quartzite of fluvial to possibly marginally marine origin. Includes quartz-pebble conglomerate, claystone (catlinite, also called pipestone), a basal (rhyolite) pebble conglomerate in Pipestone County, and a basal (granite, quartz, chert, iron-formation) conglomerate in Nicollet County on the Minnesota River

Lithology: quartzite; conglomerate; claystone

Cretaceous rocks, undivided (Cretaceous) at surface, covers 82 % of this area

Cretaceous rocks, undivided - Dakota, Graneros, Greenhorn, Carlie, Niobara, and Pierre formations and their nonmarine equivalents in northwestern, southwestern, and southeastern Minnesota

Lithology: shale; sandstone; limestone

Upper and Middle Ordovician rocks, undivided (Late and Middle Ordovician) at surface, covers 4 % of this area

Upper and Middle Ordovician rocks, undivided - Limestone and shaly limestone of the Maquoketa and Dubuque Formations, and limestone and dolostone of the Galena Group in the Hollandale embayment of southeastern Minnesota

Lithology: limestone; dolostone (dolomite)