SUPPORTED IN PART BY THE MINNESOTA MINERALS DIVERSIFICATION PROGRAM MISCELLANEOUS MAP SERIES AS RECOMMENDED BY THE MINERALS COORDINATING COMMITTEE FOR THE MINNESOTA LEGISLATURE MAP M-119, SHEET 2 OF 2 MINNESOTA GEOLOGICAL SURVEY D.L. Southwick, Director CORRELATION OF MAP UNITS 91°00' SEDI- MENTARY ROCKS kfdl NORTH SHORE VOLCANIC GROUP MISCELLANEOUS 90°15' INTRUSIONS BEAVER BAY COMPLEX CANADA nsl 90°30' 90°45' 90°00' bsb 91°15' Gunflint Lake Knife Lake bbr 91°30' Tuscarora 89°45' 89°30' Lake Cucumber Poplar Lake Lake bsl bvh bms er 48°00' DULUTH COMPLEX iv R Pigeon Winchell Lake Pig TY e Point Layered Series bfg 91°45' on N Misquah bhc 48°00' Newton U Grand bcl bbl Hills 91°00' mdg mgp dlol dlbe dld bll bum Lake Portage bdf mdn Anortho- Fall CO Br nneu nnu nswu dlwl dlgl dlbl bfm E

Midcontinent sitic ule Lake K COOK COUNTY 89°45' rift system dll3 Series bwl Mesoproterozoic Brule Lake

dll1 dlsk dlwm LA CANADA 90°15' dlt dltu er Eagle* Pine* R 90°30' i nsu nhu Mountain Mountain v 90°45' dlpr dau bcc blp Riv e Gunflint Lake 90°00' r Hovland 91°15' PROTEROZOIC 92°00' Ely Farm Knife Lake Lake 91°30' 89°45' 89°30' bsp White wishiwi P Iron Ka 90°00' Poplar Lake Cucumber ige on er 48°00' Normal rk Tuscarora Lake iv Pigeon Lake o Lake Winchell Lake R F Point MAGNETIC POLARITY BOUNDARY Reverse 91°45' Early Gabbroic Felsic Series 48°00' Misquah Grand Marais Newton Grand Series South Lake Hills mbl 90°15' Portage 47°45' Fall B dep dec dfwl dfbl dfwf dfmw dfu ru mls Lake le nnel nru Brule Lake 89°45' dfcl dfmh 47°45' Toohey Lake Good Eagle Pine mdr R Harbor er * * Mountain nswl iv Mountain iv 90°30' R e Bay r Y Hovland Birch Lake 92°00' Ely Farm i Y kps Lake hiw Fourmile is White w ANIMIKIE GROUP Lake

a TY Iron K 90°00'

N . k TY r Cross

Lake or Ptm Pvr Prv C U F N htali g th ug n Lutsen

u U o So Grand Marais Penokean Orogen Pbi Pgi Paleoproterozoic H 90°15' Riv LAKE COUNT COOK COUNT

47°45' Ppk CO 90°45'

r CO IS er

e E Ninemile v U 47°45' Toohey Lake Good SUPRACRUSTAL N. Ri K Br a Lake

Harbor ROCKS LO nch

Tofte 90°30' LA . Osier Birch Lake Bay INTRUSIVE ROCKS idge Fourmile tr Lake r ST Y Lake Akn a ch Ma Schroeder T n Y P Seven a

N . n T r C . Br C Superior Province Ag Late Archean ARCHEAN S i

U Beaver t N htali g r Alv Apda Greenwood ou

ug n o Lutsen Blesner O s U o (Neoarchean) H s Amv Am 92°15' Lake Lake 47°30'

C Riv O R Anl Aeg Sonju Lake i

C v 90°45' 47°30' Hoyt Lakes S

I e r Lake er E Ninemile W U N. 91°00' K B e

r O ra Lake st Br e A iv L nc Tofte L h R . Osier River e T s . . Lake Cloquet Br Y

g S M LAKE COUNT id nch Schroeder . Loui tr Seven ra a Lake Bapt East R r S. B n St a Beaver Greenwood it Finland P Blesner o DESCRIPTION OF MAP UNITS Lake Lake u 47°30' Anorthositic series PALEOPROTEROZOIC ROCKS i Little Marais 92°15' bum Upper Manitou gabbro sm O Lake R 47°30' Sonju iv I Hoyt Lakes W Lake e MESOPROTEROZOIC ROCKS r 91°00' dau Undifferentiated anorthositic rocks Animikie Group es t Ri s B bhc Houghtaling Creek troctolite R ui River r. r. North Shore Volcanic Group v Illgen Lo t B Ptm Thomson Formation Be Lax e t. as r City S Cloquet B E R a E a Normal magnetic polarity suites Felsic series v Lake Lake p Finland er t bdf Dam Five gabbronorite is Little Marais O Palisade Head m Pvr Virginia Formation Silver Bay P I nsl Schroeder–Lutsen basalts dfmw Mt. Weber granophyre R bwl Wilson Lake ferrogabbro iv R 0 10 20 mi U Illgen 91°15' B Lax e e r City Prv Rove Formation Riv a E nneu Upper northeast sequence dfwf Whitefish Lake granophyre v Lake 0 10 20 30 km S e er Beaver Bay r Palisade Head bfm Fourmile Lake ferrogabbro 47°15' P 47°15' Silver Bay Pbi Biwabik Iron Formation LOCATION DIAGRAM nswu Upper southwest sequence dfbl Beth Lake granophyre R U iv 91°15' e bcc Cabin Creek porphyritic diorite r Beaver Bay S Gooseber 47°15' dfwl Wine Lake monzodiorite Pgi Gunflint Iron Formation E 47°15' nnu Undifferentiated rocks Split Rock Point blp Leveaux porphyritic diorite ry K EXPLANATION Ppk Pokegama Formation Si Ri G dfmh Misquah Hills granophyre lv ve oos E e r eb Reverse magnetic polarity suites r A erry Split Rock Point K bsp Shoepack Lake inclusion-rich diabase Silver S R L ilv ive Creek e r A Bedrock is moderately well exposed—Density of outcrop is sufficient dfcl Cucumber Lake granophyre r nnel Lower northeast sequence ARCHEAN ROCKS Silver to map at 1:24,000 or smaller scale 91°30' Creek L Duluth Complex intrusions Intrusive rocks Cr 91°30' dfu Undifferentiated rocks e nswl Lower southwest sequence e C Layered series k re e Bedrock is poorly exposed—Mapping requires additional data from k Apda Porphyritic dacite to andesite drilling and geophysical maps dld Layered series at Duluth Early gabbroic series nru Undifferentiated rocks SCALE 1:500,000 Ag Granitoid bodies dec Crocodile Lake gabbro Two Harbors 0 10 20 mi Two Harbors Scant to no exposure of bedrock—Geology inferred almost exclu- Rocks of unknown magnetic polarity dlol Osier Lake intrusion 47°00' sively from geophysical maps and scattered drill holes 47°00' 47°00' 47°00' Am Mafic to ultramafic intrusions dep Poplar Lake intrusion 0 10 20 30 km nsu Undifferentiated rocks dlbe Bald Eagle intrusion L 91°45' Drill hole e L 91°45' s e te Supracrustal rocks st r e nhu Volcanic hornfels dlbl Boulder Lake intrusion Miscellaneous intrusions r R iv er Basal contact of the Duluth Complex Akn Knife Lake Group Riv mdg Diabase-to-gabbro intrusions Beaver Bay Complex intrusions dlgl Greenwood Lake intrusion er Alv Lake Vermilion Formation mgp Granophyre intrusion bsb Silver Bay intrusions dlwl Wilder Lake intrusion 92°00' Duluth Anl Newton Lake Formation bbr Beaver River diabase mdn Diabase dikes of normal polarity dlwm Western margin intrusion 92°00' Aeg Ely Greenstone . Diabase dikes of reverse polarity 46°45' 46°45' bsl Sonju Lake intrusion dlsk South Kawishiwi intrusion mdr

N CO N r e Duluth v Amv Mafic volcanic rocks TO i mbl Brule Lake porphyry intrusions Elys R bvh Victor Head diabase dll1 Lake One intrusion . Peak 46°45' 46°45' ThomsonCARL is

* N CO u mls Logan sills MAP SYMBOLS r o bms Milepost 7 intrusion dll3 Lake Three intrusion e Fond L v . TO du 92°15' t Ri Lac S Geologic contact Elys Peak bfg Finland granophyre dlpr Partridge River intrusion Sedimentary rocks CARL Thomson is Mafic sill * u GENERALIZED DENSITY OF BEDROCK OUTCROPS AND DRILL HOLES IN NORTHEASTERN MINNESOTA o kfdl Fond du Lac Formation L bcl Cloquet Lake layered series dlt Tuscarora intrusion Fond 92°15' t. Mafic dike of unknown polarity du S kps Puckwunge Sandstone Lac bll Lax Lake gabbro dltu Undifferentiated troctolitic rocks

bbl Blesner Lake diorite MAP SHOWING TIME-STRATIGRAPHIC RELATIONSHIPS WITHIN THE DULUTH COMPLEX AND RELATED ROCKS, NORTHEASTERN MINNESOTA

91° 00'

13 Davidson, D.M., and Burnell, J.R., 1977, Reconnaissance geologic map of Brule Miller, J.D., Jr., Green, J.C., Severson, M.J., Chandler, V.W., Hauck, S.A., Peterson, 92°00' 91°30' 91°00' 90°30' 90°00' 89°30' Lake quadrangle, Cook County, Minnesota: Minnesota Geological Survey D.M., and Wahl, T.E., 2002, Geology and mineral potential of the Duluth Complex 90°15' 90° 90°30' Miscellaneous Map Series M-29, scale 1:24,000. and related rocks of northeastern Minnesota: Minnesota Geological Survey 91° 45' 90° Report of Investigations 58. Davis, D.W., and Green, J.C., 1997, Geochronology of the North American 15' 00' Midcontinent rift in western Lake Superior and implications for its geodynamic 52 Miller, J.D., Jr., and Jerde, E.A., 1990–1993 [unpublished field notes and maps C 91°30' A evolution: Canadian Journal of Earth Sciences, v. 34, p. 276–488. from Little Marais quadrangle]. 89°45' 89°30' N Davis, D.W., and Sutcliffe, R.H., 1985, U-Pb ages from the Nipigon plate and Miller, J.D., Jr., and Ripley, E.M., 1996, Layered intrusions of the Duluth Complex, U A . 48°00' S D northern Lake Superior: Geological Society of America Bulletin, v. 96, p. Minnesota, USA, in Cawthorn, R.G., ed., Layered intrusions: Developments in . A 1572–1579. Petrology 15; New York, Elsevier Science, p. 257–301. 91°45' 37 Foose, M.P., and Cooper, R.W., 1978, Preliminary geologic map of the Harris 36 Morey, G.B., and Cooper, R.W., 1977, Bedrock geology of the Hoyt Lakes–Kawishiwi 48°00' Lake area, northeastern Minnesota: U.S. Geological Survey Open-File Report area, St. Louis and Lake Counties, northeastern Minnesota: Minnesota Geological 78-385, 24 p., 1 pl., scale 1:12,000. Survey file maps, scale 1:48,000. Fralich, P.W., and Kissin, S.A., 1998, The age and provenance of the Gunflint 5 Morey, G.B., and Nathan, H.D., 1977, Geologic map of the South Lake quadrangle, CANADA lapilli tuff [extended abs.]: Institute on Lake Superior Geology, 44th Annual Cook County, Minnesota: Minnesota Geological Survey Miscellaneous Map 89° Meeting, Minneapolis, Minn., 1998, Proceedings, v. 44, pt. 1—Program and Series M-38, scale 1:24,000. 45' U.S. abstracts, p. 66–67. 4 ———1978, Geologic map of the Gunflint Lake quadrangle, Cook County, 1 31 Green, J.C., [1966–2000, unpublished field notes and maps from locations along Minnesota: Minnesota Geological Survey Miscellaneous Map Series M-42, 92°00' 2 3 4 5 6 the North Shore]. scale 1:24,000. 48°00' ———1972, North Shore Volcanic Group, in Sims, P.K., and Morey, G.B., eds., 3 Morey, G.B., Weiblen, P.W., Papike, J.J., and Anderson, D.H., 1981, Geologic 90° map of the Long Island Lake quadrangle, Cook County, Minnesota: Minnesota 48°00' Geology of Minnesota: A centennial volume: St. Paul, Minnesota Geological 00' 7 Survey, p. 294–332. Geological Survey Miscellaneous Map Series M-46, scale 1:24,000. 11 10 9 8 34 ———1982, Geologic map of Minnesota, Two Harbors sheet: Minnesota Geological 63 Motamedi, S., 1984, The Keweenawan lavas in the City of Duluth: Duluth, University 15 14 13 Survey, scale 1:250,000. of Minnesota, M.S. thesis, 140 p. 90°15' 22 17 16 47°45' 18 51 ———1992, Geologic map of the North Shore of Lake Superior, Lake and Cook 7 Mudrey, M.G., Jr., 1977, Geologic map of Pigeon Point quadrangle, Cook County, Ely 21 20 47°45' 19 12 Counties, Minnesota: Part 1. Little Marais to Tofte: Minnesota Geological Survey Minnesota: Minnesota Geological Survey Miscellaneous Map Series M-36, Miscellaneous Map Series M-71, scale 1:24,000. scale 1:24,000. 90°30' 23 29 (Cook Co.) Green, J.C., Bornhorst, T.J., Chandler, V.W., Mudrey, M.J., Jr., Myers, P.E., Pesonen, 12 Nelson, N., 1991, A petrologic and geochemical study of granophyric granite in 24 25 26 27 28 89°30' Grand L.J., and Wilband, J.T., 1987, Keweenawan dykes of the Lake Superior region: the roof of the Keweenawan Duluth Complex, Eagle Mountain, Cook County, 39 Marais Evidence of evolution for the middle Proterozoic Midcontinent rift of North Minnesota: Duluth, University of Minnesota, M.S. thesis, 151 p. America, in Hall, H.C., and Rarhig, W.F., eds., Mafic dyke swarms: Geological Paces, J.B., and Miller, J.D., Jr., 1993, Precise U-Pb ages of Duluth Complex and

. Association of Canada Special Paper 34, p. 289–302. . related mafic intrusions, northeastern Minnesota: Geochronological insights 37 35 O

O 92°15'

C 32

Green, J.C., Davis, D.W., and Schmitz, M.D., 2001, Three new zircon dates for the to physical, petrogenetic, paleomagnetic and tectono-magmatic processes C

90° K

40 E Midcontinent rift, North Shore, Minnesota: More data, more questions [extended associated with the 1.1 Ga Midcontinent rift system: Journal of Geophysical O

34 33 K 45'

O abs.]: Institute on Lake Superior Geology, 47th Annual Meeting, Madison, Wisc., Research, v. 98, no. B8, p. 13,997–14,013.

41 A C 38 36 L 42 43 2001, Proceedings, v. 47, Pt. 1–Program and abstracts, p. 29. 48 Patelke, R.L., 1996, The Colvin Creek body, a metavolcanic and metasedimentary 30,31 30 Green, J.C., Jirsa, M.A., and Moss, C.M., 1977, Environmental geology of the mafic inclusion in the Keweenawan Duluth Complex, northeastern Minnesota: North Shore: Minnesota Geological Survey, 99 p. Duluth, University of Minnesota, M.S. thesis, 232 p. 44 90°00' 46 21 Green, J.C., Phinney, W.C., and Weiblen, P.W., 1966, Geologic map of Gabbro Peterson, D.M., Gallup, Christina, Jirsa, M.A., and Davis, D.W., 2001, Correlation of 45 47 49 50 47°30' Lake quadrangle, Lake County, Minnesota: Minnesota Geological Survey Archean assemblages across the U.S.–Canadian border: Phase 1 geochronology 47°30' 51 Miscellaneous Map Series M-2, scale 31,680. [extended abs.]: Institute on Lake Superior Geology, 47th Annual Meeting, 48 47°30' 91° 47°30' 22 Green, J.C., and Schulz, K.J., 1982, Geologic map of the Ely quadrangle, St. Louis Madison, Wisc., 2001, Proceedings, v. 47, pt. 1–Program and abstracts, p. 52 and Lake Counties, Minnesota: Minnesota Geological Survey Miscellaneous 77–78. 00' 53 Map Series M-50, scale 1:24,000. 23 Peterson, D.M., and Jirsa, M.A., compilers, 1999, Bedrock geologic map and R 54 35 Green, J.C., and Venske, E.A., 1990, Drift pebble lithology of the Tomahawk road mineral exploration data of the western Vermilion district, St. Louis and Lake 56 area, Lake County, Minnesota: File report of the Minnesota Department of Counties, northeastern Minnesota: Minnesota Geological Survey Miscellaneous O R Natural Resources, Division of Minerals. Map Series M-98, scale 1:48,000. I 55 58 24 Phinney, W.C., 1967, Reconnaissance geologic map of part of the Kangas Bay IO 41 Griffin, W.L., and Morey, G.B., 1969, The geology of the Issac Lake quadrangle, R St. Louis County, Minnesota: Minnesota Geological Survey Special Publication quadrangle: Minnesota Geological Survey file map, scale 1:24,000. R 90°30' E 57 E Series SP-8, 57 p., 1 pl. in pocket. 19 ———1967–1969 [unpublished field notes and maps, Lake Insula, Snowbank P Grout, F.F., 1949–1950, The titaniferous magnetites of Minnesota: St. Paul, Office of Lake, Quagda Lake, Isabella Lake, Alice Lake, Ensign Lake East, Kekakabic P U the Commissioner of the Iron Range Resources and Rehabilitation, 117 p. Lake, Ogishkemuncie Lake 7.5-minute quadrangles]. U S 18 ———1972, Northwestern part of the Duluth Complex, in Sims, P.K., and Morey, Y 29 Grout, F.F., Sharp, R.P., and Schwartz, G.M., 1959, The geology of Cook County, 91°15' T G.B., eds., Geology of Minnesota: The centennial volume: Minnesota Geological S 59 N Minnesota: Minnesota Geological Survey Bulletin 39, 163 p., 16 pls. on 17 47°15'

U Survey, p. 335–353.

TY sheets (in pocket). 47°15' O

N E 60 Pope, N.M., 1976, Petrology and structure of the Late Precambrian mafic sills C U

K 1 Gruner, J.W., Dutton, C.E., Gibson, G.R., and Grout, F.F., 1941, Structural geology O S east of Silver Creek, Lake County, Minnesota: Duluth, University of Minnesota,

I of the Knife Lake area of northeastern Minnesota: Geological Society of America C

A E U M.S. thesis, 157 p. MAP

E L Bulletin, v. 52, no. 10, p. 1577–1642.

K LO

Reichhoff, J.A., 1987, Two Keweenawan basaltic dike swarms in the Duluth area, K

. Halls, H.C., and Pesonen, L.J., 1982, Paleomagnetism of Keweenawan rocks, in T

LA AREA Minnesota: Duluth, University of Minnesota, M.S. thesis, 168 p. S 91°00' Wold, R.J., ed., Geology and tectonics of the Lake Superior Basin: Geological A 60 0 10 20 mi Society of America Memoir 156, p. 173–201. Sandland, T.O., Wirth, K.R., Vervoort, J.D., Gehrels, G.E., Kennedy B.C., and L Jerde, E.A., 1991, Geochemistry and petrology of hypabyssal rocks associated Harpp, K.S., 2001, Roles of fractional crystallization and assimilation in the 47°00' 47°00' 0 10 20 30 km with the Midcontinent Rift, northeastern Minnesota: Los Angeles, University of production of Midcontinent rift granophyres [extended abs.]: Institute on Lake 91° California, Ph.D. dissertation, 305 p. Superior Geology, 47th Annual Meeting, Madison, Wisconsin, 2001, Proceedings, 30' v. 47, pt. 1, Programs and abstracts, p. 85–86. Jirsa, M.A., 1984, Interflow sedimentary rocks in the Keweenawan North Shore 42 Severson, M.J., 1993 [unpublished field notes and maps from Peter Mitchell 30,31 Volcanic Group, northeastern Minnesota: Minnesota Geological Survey Report 61,62 of Investigations 30, 20 p. Mine area]. 8 Jones, N.W., 1963, The relationships between the Duluth gabbro and the dikes 25 ———1994, Igneous stratigraphy of the South Kawishiwi intrusion, Duluth Complex, northeastern Minnesota: Duluth, University of Minnesota, Natural Resources and sills in the vicinity of Hovland, Minnesota: Minneapolis, University of 47°00' 47°00' INDEX TO MAPPING IN NORTHEASTERN MINNESOTA Minnesota, M.S. thesis, 90 p. Research Institute Technical Report NRRI/TR-93/34, 210 p. + plates. Duluth 59 ———1995, Geology of the southern portion of the Duluth Complex: Duluth, 91°30' 64 Kilburg, J.A., and Morey G.B., 1977, Reconnaissance geologic map of the Esko 91° ST. LOUIS CO. University of Minnesota, Natural Resources Research Institute Technical Report 63 quadrangle, St. Louis and Carlton Counties, Minnesota: Minnesota Geological 45' CARLTON CO. Survey Miscellaneous Map Series M-25, scale 1:24,000. NRRI/TR-95/26, 185 p. + plates. 6 Mathez, E.A., Nathan, H.D., and Morey, G.B., 1977, Geologic map of the Hungry 46 ———1995 [unpublished field notes, maps, and drill logs from Dunka Road 64 Jack Lake quadrangle, Cook County, Minnesota: Minnesota Geological Survey deposit area]. Miscellaneous Map Series M-39, scale 1;24,000. 39 ———1999 [unpublished field notes, maps, and drill logs from Birch Lake area]. SCALE 1:500,000

44 Meineke, D.G., Buchheit, R.L., Dahlberg, E.H., Morey, G.B., and Warren, L.E., 56 Severson, M.A., and Hauck, S.A., 1990, Geology, geochemistry, and stratigraphy 0 10 20 mi 1993, Geologic map, Mesabi Iron Range, Minnesota: Hibbing, Minn., Mesabi of a portion of the Partridge River intrusion: Duluth, University of Minnesota, 92°00' Iron Range Geological Society; also insert in Institute on Lake Superior Geology, Natural Resources Research Institute Technical Report NRRI/GMIN-TR-89-11, 92° 0 10 20 30 km 236 p. + plates. 39th Annual Meeting, Eveleth, Minn., 1993, Proceedings, v. 39, Pt. 2, Field 00' trip guidebook. 45 Severson, M.A., and Miller, J.D., Jr., 1999, Bedrock geologic map of the Allen 20 Miller, J.D., Jr., 1986, The geology and petrology of anorthositic rocks in the Duluth quadrangle, St. Louis County, Minnesota: Minnesota Geological Survey ———1974, Geology of the Ely–Hoyt Lakes district, northeastern Minnesota: accompanying discussion: The Duluth Complex in the Perent Lake and Kawishiwi Complex, Snowbank Lake quadrangle, northeastern Minnesota: Minneapolis, Miscellaneous Map Series M-91, scale 1:24,000. See Chandler (2001) for the original aeromagnetic data and additional information REFERENCES CITED AND INDEX TO MAPPING 46°45' Minnesota Geological Survey file report, 30 p., accompanying materials in Lake quadrangles, Lake and Cook Counties, Minnesota, 10 p. University of Minnesota, Ph.D. dissertation, 2 vols., 525 p., 2 pls. in pocket. 43 Severson, M.A., Patelke, R.L., Hauck, S.A., and Zanko, L.M., 1994, The Babbitt 46°45' concerning the collection and processing of Duluth Complex geophysical data References prefaced by numbers are shown on the above Index to Mapping envelope. 17 ———1977g, Reconnaissance geologic map of Alice Lake quadrangle, Lake 57 ———1988, Geologic map of the Silver Bay and Split Rock Point NE quadrangles, copper-nickel deposit, Part B: Structural datums: Duluth, University of Minnesota, Chandler, V.W., [n.d., unpublished magnetic polarity data of the Minnesota County, Minnesota: Minnesota Geological Survey Miscellaneous Map Series Lake County, Minnesota: Minnesota Geological Survey Miscellaneous Map Natural Resources Research Institute Technical Report NRRI/TR-94/21b, 48 American Association of Petroleum Geologists, 1983, North American stratigraphic Geological Survey]. M-33, scale 1:24,000. Series M-65, scale 1:24,000. p. + plates. code: AAPG Bulletin, v. 67, no. 2, p. 841–875. Chandler, V.W., 1983a, Aeromagnetic map of Minnesota, Cook and Lake Counties: 28 ———1977a, Reconnaissance geologic map of Beth Lake quadrangle, Cook 32 ———1993 [unpublished field notes and maps, Lutsen–Caribou Lake area]. Streckeisen, A., 1976a, Classification of the common igneous rocks by means County, Minnesota: Minnesota Geological Survey Miscellaneous Map Series 2 Beitsch, Sandy, and Weiblen, P.W., 1980, unpublished field map of the Gillis Minnesota Geological Survey Aeromagnetic Map Series A-1, 2 pls., scale 50 Miller, J.D., Jr., Boerboom, T.J., and Jerde, E.A., 1994, Bedrock geologic of their chemical composition—a provisional attempt: Neues Jahrbuch fuer M-26, scale 1:24,000. Lake quadrangle. 1:250,000. map of the Cabin Lake and Cramer quadrangles, Lake and Cook Counties, Mineralogie Monatshefte 1, p. 1–15. 92°15' 33 Boerboom, T.J., and Miller, J.D., Jr., 1994, Geologic map of the Silver Island ———1983b, Aeromagnetic map of Minnesota, St. Louis County: Minnesota 14 ———1977d, Reconnaissance geologic map of Cherokee Lake quadrangle, Cook Minnesota: Minnesota Geological Survey Miscellaneous Map Series M-82, ———1976b, To each plutonic rock its proper name: Earth-Science Reviews, Lake, Wilson Lake, and western Toohey Lake quadrangles, Lake and Cook Geological Survey Aeromagnetic Map Series A-2, 2 pls., scale 1:250,000. County, Minnesota: Minnesota Geological Survey Miscellaneous Map Series scale 1:24,000. v. 12, no. 1, p. 1–33. Counties, Minnesota: Minnesota Geological Survey Miscellaneous Map Series M-30, scale 1:24,000. ———1990, Geologic interpretation of gravity and magnetic data over the central 54 Miller, J.D., Jr., and Chandler, V.W., 1999, Bedrock geologic map of the central Taylor, R.B., 1964, Geology of the Duluth Gabbro Complex near Duluth Minnesota: M-81, scale 1:24,000. 11 ———1977c, Reconnaissance geologic map of Eagle Mountain quadrangle, Cook Minnesota Geological Survey Bulletin 44, 62 p. part of the Duluth Complex, northeastern Minnesota: Economic Geology, v. Duluth Complex and the western part of the Beaver Bay Complex, Lake and St. County, Minnesota: Minnesota Geological Survey Miscellaneous Map Series Boerboom, T.J., and Zartman, R.E., 1993, Geology, geochemistry, and geochron- 85, p. 816–829. Louis Counties, Minnesota: Minnesota Geological Survey Miscellaneous Map ology of the central Giants Range batholith, northeastern Minnesota: Canadian M-28, scale 1:24,000. Series M-101, scale 1:100,000. Every reasonable effort has been made to ensure the accuracy of the factual data on ———2001, Superimposed magnetic on gravity anomaly map of the Duluth Journal of Earth Sciences, v. 30, no. 12, p. 2510–2522. 15 ———1977b, Reconnaissance geologic map of Kelso Mountain quadrangle, Cook 61 Miller, J.D., Jr., and Green, J.C., 1992–2000 [unpublished field notes and maps, which this map interpretation is based; however, the Minnesota Geological Survey does not Complex and related rocks, northeastern Minnesota: Minnesota Geological County, Minnesota: Minnesota Geological Survey Miscellaneous Map Series Duluth area]. warrant or guarantee that there are no errors. Users may wish to verify critical information; 40 Bonnichsen, Bill, 1970b [Reconnaissance geologic map of Babbitt quadrangle]: Survey Miscellaneous Map Series M-120, scale 1:200,000. M-27, scale 1:24,000. sources include both the references listed here and information on file at the offices of the Minnesota Geological Survey file map, scale 1:24,000. 58 Miller, J.D., Jr., Green, J.C., and Boerboom, T.J., 1989, Geology of the Illgen Corfu, F., and Stott, G.M., 1998, Shebandowan greenstone belt, western Superior Minnesota Geological Survey in St. Paul. In addition, effort has been made to ensure that the 16 ———1977h, Reconnaissance geologic map of Lake Polly quadrangle, Lake and City quadrangle, Lake County, Minnesota: Minnesota Geological Survey 38 ———1970a [Reconnaissance geologic map of Babbitt NE quadrangle]: Minnesota Province: U-Pb ages, tectonic implications, and correlations: Geological Society interpretation conforms to sound geologic and cartographic principles. No claim is made that Cook Counties, Minnesota: Minnesota Geological Survey Miscellaneous Map Miscellaneous Map Series M-69, scale 1:24,000. Geological Survey file map, scale 1:24,000. of America Bulletin, v. 110, p. 1467–1484. the interpretation shown is rigorously correct, however, and it should not be used to guide Series M-34, scale 1:24,000. 53 Miller, J.D., Jr., Green, J.C., Boerboom, T.J., and Chandler, V.W., 1993, Geologic map 49 ———1970d [Reconnaissance geologic map of Babbitt SE quadrangle:] Minnesota engineering-scale decisions without site-specific verification. 27 Davidson, D.M., Jr., 1969a, Geologic map of the Kawishiwi Lake quadrangle, Lake 10 ———1977f, Reconnaissance geologic map of Lima Mountain quadrangle, Cook of the Doyle Lake and Finland quadrangles, Lake County, Minnesota: Minnesota Geological Survey file map, scale 1:24,000. and Cook Counties, Minnesota: Minnesota Geological Survey Miscellaneous County, Minnesota: Minnesota Geological Survey Miscellaneous Map Series Geological Survey Miscellaneous Map Series M-72, scale 1:24,000. 47 ———1970c [Reconnaissance geologic map of Babbitt SW quadrangle]: Minnesota Map Series M-7, scale 1:24,000; accompanying discussion: The Duluth Complex M-32, scale 1;24,000. 62 Miller, J.D., Jr., Green, J.C., and Chandler, V.W., 1993, Preliminary geologic map of FIRST VERTICAL DERIVATIVE OF THE AEROMAGNETIC DATA REDUCED TO POLE Geological Survey file map, scale 1:24,000. in the Perent Lake and Kawishiwi Lake quadrangles, Lake and Cook Counties, 9 ———1977e, Reconnaissance geologic map of Pine Mountain quadrangle, Cook the Duluth area, St. Louis County, Minnesota, plate 1 [of Duluth mapping project]: Minnesota, 10 p. 55 ———1971, Outcrop map of southern part of Duluth Complex, and associated County, Minnesota: Minnesota Geological Survey Miscellaneous Map Series Minnesota Geological Survey Open-File Report 93-2, scale 1:48,000. Keweenawan rocks, St. Louis and Lake Counties, Minnesota: Minnesota 26 ———1969b, Geologic map of Perent Lake quadrangle, Lake County, Minnesota: M-31, scale 1:24,000. NORTHEASTERN MINNESOTA AND ADJACENT AREAS OF THE UNITED STATES AND CANADA Geological Survey Miscellaneous Map Series M-11, scale 1:125,000. Minnesota Geological Survey Miscellaneous Map Series M-8, scale 1:24,000;

GEOLOGIC MAP OF THE DULUTH COMPLEX AND RELATED ROCKS, NORTHEASTERN MINNESOTA By J.D. Miller, Jr. J.C. Green M.J. Severson V.W. Chandler D.M. Peterson Final cartographic and digital preparation of the two printed sheets that constitute Minnesota Geological Survey Professor Emeritus Natural Resources Research Institute Natural Resources Research Institute this Miscellaneous Map was done by staff members of the Minnesota Geological Minnesota Geological Survey Survey. The work included editing, graphic design, and manipulation and preparation University of Minnesota–Duluth University of Minnesota–Duluth University of Minnesota–Duluth of the final digital data and map products by T.E. Wahl, R.S. Lively, M.A. Jirsa, Philip Heywood, and Lori Robinson. 2001