Geologic units in Lake county, Minnesota

Additional scientific data in this geographic area

Anorthositic intrusions and inclusions, undifferentiated (Mesoproterozoic) at surface, covers 24 % of this area

Anorthositic intrusions and inclusions, undifferentiated (~1,099 Ma).

Gabbro (Mesoproterozoic) at surface, covers 11 % of this area

Gabbro. Includes the Western Margin, Greenwood Lake, Bald Eagle (~1,098), Lake One, Lake Three, Wilder Lake, and Osier Lake intrusions.

Gabbro, ferrogabbro, and gabbronorite (Mesoproterozoic) at surface, covers 10 % of this area

Gabbro, ferrogabbro, and gabbronorite. Includes the Lax Lake and Cloquet Lake gabbros, Sonju Lake (~1,096 Ma), Dam Five, Wilson Lake (~1,096 Ma), Fourmile Lake, and Upper Manitou intrusions (~1,096 Ma).

Undifferentiated mafic to felsic lava flows (Mesoproterozoic) at surface, covers 7 % of this area

Undifferentiated mafic to felsic lava flows. Includes the Lakeside, Lakewood, and Cross River lavas.

Gabbroic intrusions (Mesoproterozoic) at surface, covers 6 % of this area

Gabbroic intrusions. Including the Sawmill, London, Brule River, Hovland, and Pigeon Point intrusions.

Troctolite (Mesoproterozoic) at surface, covers 5 % of this area

Troctolite. Includes the Boulder Lake, Tuscarora (~1,099 Ma), Partridge River (~1,098 Ma), South Kawishiwi, and part of the Western Margin intrusions.

Basalt and basaltic andesite (Mesoproterozoic) at surface, covers 4 % of this area

Basalt and basaltic andesite. Includes the Leif Erickson, Lakeside (~1,098 Ma), Sucker River, Larsmont, Two Harbors, Crow Creek, Gooseberry River, Gustafson Hill, Baptism River, Good Harbor Bay, Cascade River, Croftville, Red Cliff, and Marr Island lavas.

Knife Lake Group volcanogenic lithic sandstone, conglomerate, siltstone, graywacke, and slate (Neoarchean) at surface, covers 4 % of this area

Volcanogenic lithic sandstone, conglomerate, siltstone, graywacke, and slate.

Diabase and ferrodiorite (Mesoproterozoic) at surface, covers 3 % of this area

Diabase and ferrodiorite. Includes the Beaver River diabase, Silver Bay (~1,096 Ma), Milepost 7, Leveaux, Shoepack Lake, Cabin Creek, and Monker Lake intrusions.

Granophyre, ferromonzodiorite, and leucogabbro (Mesoproterozoic) at surface, covers 3 % of this area

Granophyre, ferromonzodiorite, and leucogabbro. Includes the Mt. Weber (~1,106 Ma), Whitefish Lake (~1,109 Ma), Beth Lake, Misquah Hills (~1,106 Ma), and Cucumber Lake (~1,106 Ma) granophyres, and Wine Lake monzodiorite.

Granophyre and granite (Mesoproterozoic) at surface, covers 2 % of this area

Granophyre and granite. Includes the Blesner Lake, Finland (~1,098 Ma), and Cloquet Lake granophyres (~1,095 Ma).

Biotite schist of graywacke protolith, and schist-rich migmatite (Neoarchean) at surface, covers 2 % of this area

Biotite schist of graywacke protolith, and schist-rich migmatite.

Mafic metavolcanic rocks (Neoarchean) at surface, covers 2 % of this area

Mafic metavolcanic rocks. Includes minor volcaniclastic and hypabyssal intrusive rocks metamorphosed to lower greenschist to lower amphibolite facies; includes the Ely Greenstone (~2,722 Ma).

Knife Lake Group, hornblende-phyric volcanic flows, breccia, and tuff. (Neoarchean) at surface, covers 2 % of this area

Hornblende-phyric volcanic flows, breccia, and tuff.

Granite to granodiorite (Neoarchean) at surface, covers 2 % of this area

Granite to granodiorite. Variably magnetic.

Rhyolite and icelandite (Mesoproterozoic) at surface, covers 2 % of this area

Rhyolite and icelandite. Includes the Cross River, Palisade Head (~1,096 Ma), Devil Track, Maple Hill, Grand Marais, and Kimball Creek lavas.

Granite-rich migmatite (Neoarchean) at surface, covers 1 % of this area

Granite-rich migmatite. Contains neosome of variably magnetic biotite granite similar to the Lac La Croix Granite, and paleosome of tonalite to granodiorite gneiss and schist.

Troctolite, augite troctolite, and troctolitic gabbro of the Houghtaling Creek troctolite (Mesoproterozoic) at surface, covers 1 % of this area

Troctolite, augite troctolite, and troctolitic gabbro of the Houghtaling Creek troctolite (~1,099 Ma).

Undifferentiated volcanic rocks and volcanic hornfels (Mesoproterozoic) at surface, covers 1 % of this area

Undifferentiated volcanic rocks and volcanic hornfels.

Granitic intrusion (Neoarchean) at surface, covers 1 % of this area

Granitic intrusion. Includes the Sacred Heart (~2592, 2,603 Ma) and Ortonville granites, the Shannon Lake Granite (~2,674), and other intrusions having low gravity and magnetic signatures.

Felsic intrusive rocks, granophyre (Mesoproterozoic) at surface, covers 1 % of this area

Felsic intrusive rocks, granophyre. Includes parts of the Eagle Mountain (~1,098 Ma) and Pine Mountain (~1,095 to 1,098 Ma) intrusions.

Syenite, monzodiorite, granodiorite, and diorite (Neoarchean) at surface, covers 0.8 % of this area

Syenite, monzodiorite, granodiorite, and diorite. Commonly hornblende- or pyroxene-bearing; Includes the Coon Lake, Side Lake, and Linden (~2,666 Ma) plutons of north-central Minnesota.

Diabase, gabbro, and ferromonzodiorite (Mesoproterozoic) at surface, covers 0.7 % of this area

Diabase, gabbro, and ferromonzodiorite. Primarily sills including the Endion, Lester River, Silver Cliff, Stony Point, Split Rock, Lafayette Bluff, Lake Clara–Lichen Lake, Pigeon River, and Reservation River intrusions.

Mafic to ultramafic (komatiitic) volcanic rocks (Neoarchean) at surface, covers 0.7 % of this area

Mafic to ultramafic (komatiitic) volcanic rocks. Includes the Newton Lake Formation and Deer Lake sequence.

Conglomerate, lithic sandstone, and graywacke, undifferentiated (Neoarchean) at surface, covers 0.5 % of this area

Conglomerate, lithic sandstone, and graywacke, undifferentiated. Includes the Midway sequence, Seine Group, and a part of the Knife Lake Group known as the Ogishkemuncie conglomerate that contains clasts of ~2,690 Ma Saganaga Tonalite (unit Ast). Deposition of alluvial fan and fluvial sediments occurred in fault-bounded basins.

Monzonite, quartz monzonite, and granodiorite (Neoarchean) at surface, covers 0.4 % of this area

Monzonite, quartz monzonite, and granodiorite. Includes the Farm Lake phase of the Giants Range batholith.

Schroeder-Lutsen basalts (Mesoproterozoic) at surface, covers 0.4 % of this area

Unconformably overlies units described below (Mns, Mnu, Mnr, and Mnb).

Calc-alkalic volcanic and volcaniclastic rocks (Neoarchean) at surface, covers 0.3 % of this area

Calc-alkalic volcanic and volcaniclastic rocks.

Knife Lake Group conglomerate (Neoarchean) at surface, covers 0.3 % of this area

Knife Lake Group conglomerate. Clasts consist largely of hornblende-bearing volcanic rocks.

Amphibolitic schist and gneiss (Neoarchean) at surface, covers 0.2 % of this area

Amphibolitic schist and gneiss. Both extrusive and intrusive protoliths are likely.

Mafic to ultramafic hypabyssal intrusive complexes composed of gabbro, pyroxenite, diorite, and anorthosite (Neoarchean) at surface, covers 0.2 % of this area

Mafic to ultramafic hypabyssal intrusive complexes composed of gabbro, pyroxenite, diorite, and anorthosite. Includes the Mentor and Deer Lake complexes, intrusions of the Newton Lake Formation, all within the Wawa subprovince; and the UBD intrusion (~2,685 to 2,695 Ma) in the Wabigoon subprovince.

Porphyritic quartzofeldspathic dikes (Neoarchean) at surface, covers < 0.1 % of this area

Porphyritic quartzofeldspathic dikes. Typically hypabyssal intrusions associated with felsic volcanic sequences.

Gabbro, peridotite, pyroxenite, lamprophyre, and metamorphic equivalents (Neoarchean) at surface, covers < 0.1 % of this area

Gabbro, peridotite, pyroxenite, lamprophyre, and metamorphic equivalents. Includes the Oaks intrusion (~2,671 Ma) in the Wabigoon subprovince, and a ~2,639 Ma lamprophyre in the western Wawa subprovince; locally defined by variably high gravity and magnetic signatures.

Magnetic intrusions, undifferentiated (Archean) at surface, covers < 0.1 % of this area

Magnetic intrusions, undifferentiated. Typically too small to ascertain gravity expression.

Migmatite dominated by tonalitic to granodioritic neosome (Neoarchean) at surface, covers < 0.1 % of this area

Migmatite dominated by tonalitic to granodioritic neosome.