Geology of Michigan and the Great Lakes

Geology of Michigan and the Great LakesRobb Gillespie, William B. Harrison III, and G. Michael GrammerMichigan Geological Repository for Research and EducationWestern Michigan University

Potato Patch Falls,Lake Superior,Munising, Michigan.Cross-bedded sand-stone, Chapel RockMember, CambrianMunising Formation.Wave-cut platformand undercut rockledges. Trees onolder wave-cut plat-form formed duringa higher, post-glacial lake stage.Dark-colored,basaltic glacialerratic on shoreline.

Michigan

L

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The Geology of Michigan and the Great Lakes is written to augment any introductoryearth science, environmental geology, geologic, or geographic course offering, and isdesigned to introduce students in Michigan and the Great Lakes to important regionalgeologic concepts and events. Although Michigans geologic past spans the Precambrianthrough the Holocene, much of the rock record, Pennsylvanian through Pliocene, is miss-ing. Glacial events during the Pleistocene removed these rocks. However, these same glacialevents left behind a rich legacy of surficial deposits, various landscape features, lakes, andrivers. Michigan is one of the most scenic states in the nation, providing numerous recre-ational opportunities to inhabitants and visitors alike.

Geology of the region has also played an important, and often controlling, role in the patternof settlement and ongoing economic development of the state. Vital resources such as iron ore,copper, gypsum, salt, oil, and gas have greatly contributed to Michigans growth and industrialmight. Ample supplies of high-quality water support a vibrant population and strong industrialbase throughout the Great Lakes region. These water supplies are now becoming increasinglyimportant in light of modern economic growth and population demands.

This text introduces the student to the geology of Michigan and the Great Lakes region.It begins with the Precambrian basement terrains as they relate to plate tectonic events. Itdescribes Paleozoic clastic and carbonate rocks, restricted basin salts, and Niagaran pinnaclereefs. Quaternary glacial events and the development of todays modern landscapes are alsodiscussed. Coastal issues and mineral resources are detailed. Students will develop a betterappreciation for the importance of geology to the inhabitants of the region today.

About the authorsDr. Robb Gillespie is currently an Assistant Professor in the Department of Geosciencesand Research Associate with the Michigan Core Repository for Research and Education(MCRRE) at Western Michigan University. Dr. Gillespie has over 24 years experience in theoil and gas industry having worked for ARCO Oil and Gas in their domestic, international,and research groups, and for COHO Resources redeveloping old oil fields. He has also oper-ated his own oil and gas consulting business since 1992, and co-founded Tres Rios Resources,Inc. (TRR), a small oil and gas company in 1993. Dr. Gillespies geological specialty is reser-voir delineation, characterization and modeling based upon detailed stratigraphic analysis.

Dr. William B. Harrison, III is Professor Emeritus in the Department of Geosciences andDirector of the Michigan Basin Core Research Laboratory that is part of the MichiganGeological Repository for Research and Education (MGRRE) at Western MichiganUniversity. Dr. Harrison has over 34 years experience in research related to sedimentarygeology, Michigan stratigraphy and petroleum geology. He is the founder of the MichiganBasin Core Research Laboratory (1982). He taught Undergraduate and Graduate studentsat Western Michigan University for 30 years. He continues to be active in research andoutreach related to Michigan geology.

G. Michael Grammer is Director of the Michigan Geological Repository for Research andEducation at Western Michigan University and an Associate Professor in the Departmentof Geosciences. He received his B.A. from the University of South Florida, M.S. fromSouthern Methodist University and Ph.D. from the University of Miamis Rosenstiel Schoolof Marine and Atmospheric Sciences. He has been at WMU since 2002 after earlier stops inthe oil and gas industry and as a faculty member at the University of Miami. His specialtiesinclude carbonate sedimentology and sequence stratigraphy.

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35133_Geo_Michigan_Cover.qxd 11/13/07 10:26 AM Page 1

KEWEENAW

HOUGHTON

ONTONAGON BARAGA

MARQUETTEGOGEBIC

CHIPPEWA

LUCE

ALGER

SCHOOLCRAFT

IRON

DICKINSON

MACKINAC

DELTA

MENOMINEE

EMMET

CHEBOYGAN

PRESQUE ISLE

CHARLEVOIX

ALPENA

MONTMORENCY

LEELANAU

OTSEGO

ANTRIM

GRAND TRAVERSEALCONAOSCODACRAWFORDKALKASKA

BENZIE

IOSCOOGEMAWROSCOMMONMANISTEE MISSAUKEEWEXFORD

ARENAC

MASON GLADWINCLAREOSCEOLALAKE

HURON

BAY

MIDLANDISABELLAOCEANA MECOSTA

NEWAYGO

TUSCOLASANILAC

SAGINAW

GRATIOTMUSKEGON MONTCALM

LAPEER

KENT GENESEE

ST CLAIR

OTTAWA

SHIAWASSEE

CLINTONIONIA

MACOMB

OAKLAND

LIVINGSTONINGHAMEATONBARRYALLEGAN

WAYNE

WASHTENAWJACKSONCALHOUNKALAMAZOOVAN BUREN

BERRIENMONROE

LENAWEEHILLSDALEBRANCHST JOSEPHCASS

BEDROCK GEOLOGY OFLOWER PENINSULA

SALINA GROUP

BASS ISLAND GROUP

GARDEN ISLAND FORMATION

BOIS BLANC FORMATION

MACKINAC BRECCIA

SYLVANIA SANDSTONE

DETROIT RIVER GROUP

DUNDEE LIMESTONE

BELL SHALE

TRAVERSE GROUP

ANTRIM SHALE

ELLSWORTH SHALE

BEDFORD SHALE

BEREA SS & BEDFORD SH

SUNBURY SHALE

COLDWATER SHALE

MARSHALL FORMATION

MICHIGAN FORMATION

BAYPORT LIMESTONE

SAGINAW FORMATION

GRAND RIVER FORMATION

RED BEDS

BEDROCK GEOLOGY OFWESTERN UPPER PENINSULA

JACOBSVILLE SANDSTONE

FREDA SANDSTONE

NONESUCH FORMATION

COPPER HARBOR CONGLOMERATE

OAK BLUFF FORMATION

PORTAGE LAKE VOLCANICS

SIEMENS CREEK FORMATION

INTRUSIVE

QUINNESEC FORMATION

PAINT RIVER GROUP

RIVERTON IRON FORMATION

BIJIKI IRON FORMATION

NEGAUNEE IRON FORMATION

IRONWOOD IRON FORMATION

DUNN CREEK FORMATION

BADWATER GREENSTONE

MICHIGAMME FORMATION

GOODRICH QUARTZITE

HEMLOCK FORMATION

MENOMINEE & CHOCOLAY GROUPS

EMPEROR VULCANIC COMPLEX

SIAMO SLATE & AJIBIK QUARTZITE

PALMS FORMATION

CHOCOLAY GROUP

RANDVILLE DOLOMITE

ARCHEAN ULTRAMAFIC

ARCHEAN GRANITE & GNEISSIC

ARCHEAN VOL. & SEDIMENTARY

MACKINAC BRECCIA

BEDROCK GEOLOGY OFEASTERN UPPER PENINSULA

MUNISING FORMATION

TREMPEALEAU FORMATION

PRAIRIE DU CHIEN GROUP

BLACK RIVER GROUP

TRENTON GROUP

COLLINGWOOD SHALE MEMBER

UTICA SHALE MEMBER

STONINGTON FORMATION

BIG HILL DOLOMITE

QUEENSTON SHALE

MANITOULIN DOLOMITE

CABOT HEAD SHALE

BURNT BLUFF GROUP

MANISTIQUE GROUP

ENGADINE GROUP

POINT AUX CHENES SHALE

SAINT IGNACE DOLOMITE

SALINA GROUP

BASS ISLAND GROUP

GARDEN ISLAND FORMATION

BOIS BLANC FORMATION

MACKINAC BRECCIA

0 20 40 MilesDate: 11/12/99N

MichiganMICHIGAN DEPARTMENT OF NATURALRESOURCESLAND AND MINERALS SERVICES DIVISIONRESOURCE MAPPING AND AERIAL PHOTOGRAPHY

Michigan Resource Information SystemPart 609, Resource Inventory, of the Natural Resources andEnvironmental Protection Act, 1994 PA 451, as amended.

Automated from "Bedrock Geology of Michigan," 1987, 1:500,000 scale,which was compiled from a variety of sources by the Michigan Departmentof Environmental Quality, Geological Survey Division.

SOURCE

RMAP

1987 BEDROCK GEOLOGY OF MICHIGAN

From

Sta

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State of Michigan: Bedrock Geology Map

35133_Geo_Michigan_INC.qxd 11/13/07 10:27 AM Page ii

ESSENTIAL QUESTIONS TO ASKMichigan.1 Introduction

Why is the geology of Michigan important to students of physical geology and to allthe inhabitants of the state today?

Michigan.2 Precambrian and Paleozoic Geology What is the structural pattern of the sedimentary rock layers of the Michigan Lower

Peninsula that makes it a basin? What are the various regional structural or geologic elements that define the margins

of the Michigan Basin? What are the ranges of ages for sedimentary rocks in Michigans Lower Peninsula? Describe the main geologic differences in rock in Michigans Eastern and Western

Upper Peninsula.

Michigan.3 Quaternary Geology What were the main controlling factors during formation of the Great Lakes basins? When was the last glacial (Wisconsinan) event? Where did erosional and depositional glacial landscapes develop in the Great Lakes

watershed? What types of depositional landforms are found throughout Michigan? What types of modern-day coastal features are currently evolving along Michigans

shorelines? How did the inland lakes in Michigan form?

Michigan.4 Modern-Day Geologic Processes What are the two main types of shoreline found around the Great Lakes in

Michigan? Name three processes that reshape the Michigan shoreline and a depositional feature

produced by each process.

Michigan.5 Geology of Water Resources What are the two types of geologic materials that contain groundwater in Michigan?

Michigan.6 Mineral Resources What is banded iron formation (BIF)? What are the main types of copper ore? Name some of the other non-metallic mineral resources produced in Michigan.

Michigan.7 Oil, Gas, and Coal Resources When and where was oil first discovered in the Michigan Basin? What was the significance of discovering oil at the Saginaw, Muskegon, and

Mt Pleasant Fields? What geologic factors controlled the ultimate shape and size of the Albion-Scipio

Field? What oil and gas exploration and development plays were important in Michigan

in the 1970s and 1980s? In the 1990s and 2000s?

2008 Cengage Brooks/Cole, a part of Cengage Learning. ALL RIGHTS RESERVED. No part of this work covered by the copyright hereonmay be reproduced or used in any form or by any meansgraphic, electronic, or mechanical, including photocopying, recording, taping, Webdistribution or information storage and retrieval systemswithout the written permission of the publisher. The Adaptable Courseware Programconsists of products and additions to existing Brooks/Cole products that are produced from camera-ready copy. Peer review, class testing,and accuracy are primarily the responsibility of the author(s). Geology of Michigan and the Great Lakes/Robb Gillespie, William B. Harrison III,and G. Michael GrammerFirst Edition ISBN (13 digit) 978-1-426-63513-7, ISBN (10 digit) 1-426-63513-3. Printed in Canada.

35133_Geo_Michigan.qxd 11/14/07 6:21 PM Page 1

Michigan.1IntroductionThe geology of the State of Michigan is dominated by theMichigan Basin, which is an elliptical, intracratonic basinnestled against the southern margin of the Canadian Shield.The Basin occupies approximately 80,000 square miles(180,000 square kilometers), and the sedimentary rocks inthe Basin, which are predominantly Paleozoic in age, reach amaximum thickness of 16,000 feet (4,848 meters). Geologicstructures define the Basin. The core of the North AmericanCraton, the Canadian Shield, bounds the Basin from thenorthwest to the northeast. Structural arches define theremainder, with the Wisconsin and Kankakee Arches tothe southwest and the Findlay and Algonquin Arches to thesoutheast (Figure Michigan.1).

The Michigan Basin covers all of Michigans LowerPeninsula and the eastern half of the Upper Peninsula. Thewestern half of the Upper Peninsula consists of allPrecambrian-age rocks with affinities to the southern mar-gin of the Canadian Shield. Strata from Middle Cambrianthrough Upper Pennsylvanian Periods are well representedthroughout the subsurface as seen in the many oil and gaswells drilled throughout the Basin. There are also limitedoutcrops throughout the Basin, especially at the marginsnear the Great Lakes. Mesozoic rocks are poorly preservedin the Basin, with Jurassic red sandstones known only fromwell samples in isolated wells in the Basin center. Most ofthe rocks of the Michigan Basin are buried beneath thickdeposits of Pleistocene glacial drift that are the onlyCenozoic deposits known from the Basin. These sands,

gravels, and clays are stacked in complex facies relation-ships and control the patterns of topography seen in muchof the Basin. Beneath this veneer of glacial sediments is theeroded bedrock. The subcrop of the various formationsforms a series of concentric patterns that mimic the Basinmargin and that are youngest near the center and oldest atthe margin (State Bedrock Map, inside front cover). Thelocations and shapes of Lakes Michigan and Huron are alsocontrolled by the Basins bedrock geology. Geographically,the Michigan Basin is centered on Michigans LowerPeninsula, but also occupies portions of Michigans UpperPeninsula, Wisconsin, Illinois, Indiana, Ohio, and Ontario,Canada.

Natural resources abound in the Michigan Basin. Oil andnatural gas have been produced from subsurface formationsin the Basin in Michigan, Ohio, Indiana, and southwestOntario. Almost 2 billion barrels of oil and 10 trillion cubicfeet of natural gas have been produced since the late 1800s.Underground mines near Detroit have produced large quan-tities of rock salt from Silurian-age evaporite deposits.Solution mining of these salts has occurred nearer the Basincenter. Large amounts of potash, bromine, sodium, and chlo-ride have been solution mined from these layers. Limestone,dolomite, and gypsum have been extensively mined fromsurface quarries in the outcrop areas. Sand and gravel forconstruction and clay for ceramics and bricks are minedstatewide from surficial glacial deposits.

The Great Lakes of Michigan, Huron, and Erie repre-sent the greatest fresh water resources in the region. Alongwith Lakes Superior and Ontario (which are not geologicallypart of the Michigan Basin), these five Great Lakes com-prise the largest accumulation of fresh water on the earthssurface. There are also vast volumes of fresh water in theglacial drift and shallow bedrock throughout the Basin. TheGreat Lakes owe their origin to the erosional processes oflobes from the Laurentide ice sheet. The moving icescoured the areas of softer bedrock, commonly composedof shales.

Michigan.2Precambrian and PaleozoicGeologyStructuresThe sedimentary rocks that comprise the Michigan Basinare layered in a pattern like a set of nested bowls (FigureMichigan.2). The oldest layers are at the bottom, and thelayers become progressively younger moving upward. Theoldest layers outcrop at the Basin margin and occur deeperin the Basin toward its center. All the strata in thePaleozoic sedimentary rock section dip at one degree or lessin all directions toward the approximate center of the Basin,which is located just west of Saginaw Bay. The exact centerof the Basin shifts slightly throughout deposition of the

2 Michigan Geology of Michigan and the Great Lakes

Figure Michigan.1 The Michigan Basin: Basement StructuralFeatures.

Mod

ified

from

Cat

acos

inos

, Dan

iels

, and

Har

rison

199

1.


Paleozoic sediments. The entire Basin is underlain byPrecambrian rocks of varying lithologies and ages that werebrought together as this part of the North American platewas assembled during middle and late Precambrian time.These basement terranes (Catacosinos, Daniels, andHarrison 1991, fig. 302) are mixes of plutonic and vol-canic igneous rocks, along with high-grade metamorphicrocks and metasediments.

The mid-Michigan gravity anomaly is a major piece ofthe basement that follows a wide swath from the northwest-ern part of the Lower Peninsula through central Michiganand then bends dramatically to the east and intersects theGrenville Front (Figure Michigan.3). The Grenville Frontis a major plate suture boundary that extends from theCanadian Shield in central Ontario through easternMichigan and into northwest Ohio. This anomaly, which isa strong gravity high, has been modeled as a partly devel-oped crustal rift with block faulting, extensive volcanic lay-ers, and sedimentary red bed fills. Analysis of seismic dataacross the anomaly and samples from Michigans deepestborehole (McClure-Sparks et al. 1-8, in Gratiot County, at17,466 feet [5,327 meters] deep) provide good evidence asto the origin of this anomaly (Fowler and Kuenzi, 1978).This mid-Michigan rift is also thought to be connected tothe Mid-Continent Rift that runs southwesterly from theUpper Peninsula of Michigan through Wisconsin, Iowa,and Kansas. The basalt flows and volcaniclastic sedimentson the Keweenaw Peninsula and through the westernUpper Peninsula are part of this geologic feature.

Major structural features that occur in the MichiganBasin are a series of arches to the southeast and southwest.These arches define the margins of the Basin in those areas

by dictating the dip direction of the sedimentary rock layers.The Findlay and Waverly Arches in northwest Ohio and theAlgonquin Arch in southwest Ontario, Canada, separate theMichigan and Appalachian Basins. The Kankakee Arch inIndiana and the Wisconsin Arch in Illinois and Wisconsinseparate the Michigan and Illinois Basins (see FigureMichigan.1).

The Bowling Green Fault, extending into southeastMichigan from northern Ohio, and the Howell Anticline aretwo major structural features that dominate the geology inthe southeastern part of the state. Small anticlines with lessthan 100 feet (30 meters) of relief are common throughoutthe central part of the state and serve as structures to trap oiland gas. Many of these anticlines show a northwest to south-east trend to their axes. Most of these anticlines are thoughtto be produced by shearing forces associated with local base-ment faults or fracture zones that are transmitted upthrough the sedimentary section during times of crustaldeformation due to continent-scale plate collision along theeastern edge of the North American plate.

Lower Peninsula Sedimentary RocksMuch of the knowledge about the geologic section inMichigans Lower Peninsula is developed from cores(Figure Michigan.4), samples, and wireline logs in wellsand boreholes drilled during oil and gas exploration and

Michigan.2 Precambrian and Paleozoic Geology 3

Niagaran Structure map overlain by Bedrock Map withindividual well penetrations shown by blue lines.Compiled by Dr. David A. Barnes, GeosciencesDepartment, Western Michigan University

Michigan Basin StructureMaps on selected units fromPre-Cambrian Basement toDundee Ls. Overlain byBedrock Map

Figure Michigan.2 Structural maps of several formations in thesubsurface of the Michigan Basincolor patterns create a pseudo-three-dimensional effect.

Com

pile

d by

Dav

id B

arne

s.

Figure Michigan.3 Michigan Basement Provences.

Mod

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from

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, Dan

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, and

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, 199

1.


mineral resource development. More than 50,000 suchwells have been drilled in the Michigan Basin since theearly 1900s. Additionally, hundreds of thousands of shallowprivate and municipal water wells have been drilledstatewide. These water supply wells provide data about theglacial drift and shallow bedrock layers. Using this exten-sive shallow and deep well data, and the local outcrops thatmainly occur near the Great Lakes shorelines, it is possibleto reconstruct the details of Michigans subsurface geology.

Michigan has a great thickness (16,000 feet [4,880meters]) of sedimentary rocks deposited in a subsiding basinduring late Precambrian through Pennsylvanian time.Jurassic red beds and Pleistocene glacial deposits coverthese sedimentary rocks with thickness that varies from afew feet to over 1,200 feet (Figure Michigan.5). As the lastbillion years of earths history has unfolded, Michigan hasgone through many changes in environment and climate.As the North American continent drifted across the globe,continental collisions and plate movements resulted ingreatly varied conditions producing different types of sedi-mentary deposits throughout Michigan. Continental flu-vial, terrestrial, and lacustrine deposits occurred in the latePrecambrian age of central Michigan. Shallow marine set-tings dominated during most of the Paleozoic Era untildeposition of fluvial and deltaic deposits returned in thePennsylvanian Period in response to Appalachian mountainbuilding (Allegheny Orogeny).

The Middle Cambrian Mt. Simon Sandstone representsthe beginning of Paleozoic deposition in Lower Michigan.These coastal and shallow marine deposits are the start ofa thick transgressive interval of sandstone, siltstone, andshale that continues into the Upper Cambrian. Thick,shallow marine shelf deposits of dolomitic carbonatesoverlie these siliciclastic strata in the Lower Ordovician

Trempealeau and Prairie du Chien intervals. The strata fromthe Mt. Simon to the Prairie du Chien represent the SaukMegasequence of Sloss (Sloss 1963) (Figure Michigan.6).The Tippecanoe Megasequence (Sloss 1963) starts with theMiddle Ordovician shallow marine and eolian St. PeterSandstone and continues upward to the base of theDevonian. This megasequence includes shallow shelf lime-stones of the Middle Ordovician Trenton-Black RiverFormations and the Middle Silurian Niagaran reefs andoverlying Salina evaporites. These evaporites, which aremostly halite with secondary amounts of anhydrite andpotash salts, attain a thickness of over 1,000 feet (305 meters)in the Basin center and are of significant commercial value.The Kaskaskia Megasequence includes most of the rest ofMichigans Paleozoic strata. Ranging from Lower-MiddleDevonian to the top of the Mississippian, restricted carbon-ates and interbedded evaporites (mostly halite and anhy-drite) of the Lucas Formation; open marine carbonates ofthe Dundee and Traverse Formations; the black, euxinic,Antrim Shale; the fine-grained sandstones and shales ofthe Mississippian Berea and Bedford Formations; and thesandstones of the Michigan Formation are all includedin the Kaskaskia sequence. The Pennsylvanian SaginawFormation sandstones, shales, and coals are part of thesubsequent Absaroka Megasequence and present only inthe Basin center. Spotty occurrences of terrestrial red beddeposits are known in the central Basin from well samples.These red beds have been identified as Jurassic in age frompalynological analysis (Cross 1998). Pleistocene glacialdrift covers most of the bedrock strata in the LowerPeninsula. Bedrock exposures are more common in theUpper Peninsula. The best bedrock exposures are foundaround the shores of the Great Lakes and in some rivervalleys (Figure Michigan.7).


Figure Michigan.4 Michigan Geological Repository for Research and Education is the principal facility in Michigan that houses cores, samples,and other information about subsurface geology.

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son.



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MichiganDept.ofEnvironmentalQualityGeologicalSurveyDivisionHarold Fitch, State Geologist

andMichiganBasinGeologicalSociety

Stratigraphic Nomenclature Project Committee:

Principal Authors:

2000

MIC

HIG

AN

BASIN

GEOLOGICALS

OC

IETY

1936

RELATEDTERMCORRELATION

LEGEND

Limestone

Shaley

Sandy

Dolomite

Sandy

Shaley

GlacialDrift

Anhydrite/Gypsum

Reefs/Bioherms

BasementRocks

CoalBed

Sandstone

Limey

Shaley

Dolomitic

Conglomeritic

Siltstone

Shale

Sandy

Limey

Dolomitic

Salt

DOMINANTLITHOLOGYOUTCROPNOMENCLATURE SUBSURFACENOMENCLATUREGEOLOGICTIME

Acknowledgements

This work is the product of the combined efforts of the geological communities of Michigan and the surrounding states and provinces. Below are given just a representative few of the contributors:

Academia:Dr. Aureal T. Cross, Michigan State University; Dr. Robert H. Dott, Jr.,University of Wisconsin; Mr. William D. Everham, Ph.D. Candidate, Michigan Technological University.

Government: Dr. Terry R. Carter, Ontario Ministry of Natural Resources; Mr. John M. Esch, Michigan Department of Environmental Quality; Dr. Brian D. Keith,Indiana Geological Survey; Mr. Lawrence H Wickstrom, Ohio Geological Survey.

Industry:Mr. Donald J. Bailey, Consultant; Mr. Jimmy R. Myles, Scot Energy; Mr. Dan E. Pfeiffer, Pfeiffer Exploration Services.

A complete listing of all contributors will be found in the Stratigraphic Lexicon for Michigan, of which this column is an integral part.

ERA PERIOD EPOCHNORTH

AMERICANSTAGES

GROUP FORMATION MEMBER FORMATION GROUP

Killians Mbr

Collingwood Sh

Chapel Rock Mbr

Trenton Fm

Ogontz Mbr

Bay de Noc Mbr

Fiborn Ls Mbr

Cataract Gr

Burnt Bluff Gr

Manistique Gr

Salina Gr

Bass Islands Gr

Detroit River Gr

Bush Bay Fm

Rapson Creek Fm

Rockview Fm

Engadine Gr

Traverse Gr

Glacial Drift

Oronto Gr

Glacial Drift

Ionia Fm

Grand River Fm

Saginaw Fm

Parma Ss Parma Ss

Bayport Ls

Michigan Fm

Marshall Ss

Coldwater Sh

Berea Ss

Bedford Sh

Antrim Sh

Traverse Ls

Bell Sh

Dundee Ls

Lucas Fm

Amherstburg Fm

Sylvania Ss

Bois Blanc Fm

Garden Island Fm

Salina G Unit

Salina F Unit

Salina E Unit

Salina D Unit

Salina C Unit

Salina B Unit

Salina A-2 Carb

Salina A-2 Evap

Ruff Fm

Salina A-1 Evap

Cain Fm

Guelph Dol

Lockport Dol

Manistique Gr

Traverse Gr

Bass Islands Gr

Pte. aux ChenesFm

Niagara Gr

Burnt Bluff Gr

Cabot Head Sh

Manitoulin DolCataract Gr

Queenston Sh

Utica Sh

Trenton Fm

Richmond Gr

Black River Fm

Glenwood Fm

Precambrian Crystalline Basement Complex

Collingwood Sh

St.Peter Ss

Prairie du Chien Gr

Trempealeau Fm

Eau Claire Fm

Munising Gr

Mount Simon Ss

Pre-Mt. Simon Clastics

Precambrian Crystalline Basement Complex

Cenozoic

Quatern

ary

Pleistoc

ene

Mesozoic Jurassic Middle Oxfordian

ConemaughLate

Penn

sylv

ania

n

PottsvilleEarly

Mis

siss

ipp

ian

Late

Early

Meramecian

Osagian

Kinderhookian

Squaw Bay Ls

Chautauquan

Senecan

Erian

Ulsterian

Late

Middle

Early

Dev

on

ian

Pal

eozo

ic

Cayugan

Niagaran

Alexandrian

Late

Middle

Early

Cincinnatian

Mohawkian

Chazyan

Whiterockian

Canadian

Trempealeaun

Franconian

Dresbachian

Middle Proterozoic Eon

Silu

rian

Ord

ovic

ian

Cam

bri

an

Late

Middle

Early

Late

Norwood Mbr

Antrim Sh

Squaw Bay Ls

undifferentiated

undifferentiated

Detroit River Gr

Salina Gr

undifferentiated

undifferentiated

Potter Farm Mbr

Ellsworth Sh

Sunbury Sh

(western)Ellsworth Sh

(western)

Berea Ss

Bedford Sh

Sunbury Sh

(eas

tern

)

Saginaw Fm

Bayport Ls

Norway Point Mbr

Four Mile Dam MbrAlpena Ls

Genshaw Mbr

Newton Creek Mbr

Long Lake Ls

Groos Quarry Mbr

Au Train Fm

Munising Fm

Cordell Fm

Schoolcraft Fm

Hendricks Fm

Byron Fm

Lime Island Fm

Cabot Head Sh

Manitoulin Dol

Big Hill Fm

Stonington Fm

Bill's Creek Sh

Jacobsville Ss

Freda Ss

Nonesuch Sh

Copper Harbor Cgl

Archean to Middle Proterozoic Eons

Basal Cgl

Ionia Fm

Grand River Fm

Michigan Fm

Marshall Ss

Coldwater Sh

Thunder Bay Ls

Ferron Point Fm

Rockport Quarry Ls

Bell Sh

Rogers City Ls

Dundee Ls

Anderdon Ls

Lucas Fm

Amherstburg Fm

Sylvania Ss

Bois Blanc Fm

Garden Island Fm

Rasin River Dol

Put-in-Bay Dol

St. Ignace Dol

Black River Fm

Chandler Falls Mbr

Franconia Fm

Galesville SsMiner's Castle Mbr

Mac

kin

ac B

recc

ia

Mac

kin

ac B

recc

ia

(eas

tern

)

Paxton Mbr

Lachine Mbr

Upper Mbr

Richmond Gr

Wisconsinan

Dr. Paul A. CatacosinosDr. William B. Harrison IIIMr. Robert F. ReynoldsDr. David B.WestjohnMr. Mark S. Wollensak

Dr. Paul A. Catacosinos, Co-chairmanMr. Mark S. Wollensak, Co-chairman

STRATIGRAPHICPOSITION

Ionia Fm

Michigan Fm

Coldwater Sh

Antrim Sh

Dundee Ls

Lucas Fm

Amherstburg Fm

St. Ignace Dolomite

Salina B Unit

Ruff Formation

Cain Fm

Guelph Dolomite

Lockport Dolomite

Burnt Bluff Gr

Trenton Fm

Black River Fm

Glenwood Fm

St. Peter Sandstone

Prairie du Chien Gr

Trempealeau Fm

Galesville Ss

Pre-Mt. Simon Clastics

STRATIGRAPHICNOMENCLATUREFORMICHIGAN

RELATEDTERMS

Jurassic Red Beds

Clare Dolomite, Brown Lime, Stray Dolomite, Stray Sandstone, Stray-Stray Sandstone, Stray-Stray-Stray Sandstone, Triple Gyp

Coldwater Red Rock, Speckled Dolomite, Wier Sand

Charlton Black Shale Member, Elltrim,Chester Black Shale Member, Upper Black Shale,Light Antrim, Lower Black, Lower AntrimMiddle Antrim, Middle Gray Antrim, Dark Antrim,Middle Gray Shale, Unit 1A, Unit 1B, Unit 1C,Crappo Creek Grey Shale Member

Reed City Member/Dolomite/Anhydrite

Freer Sandstone, Horner Member, Iutzi Member, Massive Salt/Anhydrite, Sour Zone, Big Anhydrite,Richfield Zone/Member/Sandstone, Big Salt

Filer Sandstone, Meldrum Member, Black Lime

Salina H Unit

Big Salt, B Salt

Salina A-1 Carbonate, Rabbit Ears Anhydrite,

Salina A-0 Carbonate

Brown Niagara, Niagaran Reef, Pinnacle Reef,Engadine Dolomite

Gray Niagara, White Niagara

Clinton Formation

Cap Dolomite

Van Wert Zone, Sneaky Peak, Black River Shale

Goodwell Unit, Zone of Unconformity

Bruggers Sandstone, Jordan Sandstone,Knox Sandstone, Massive Sand

Foster Formation, New Richmond Sandstone, Lower Knox Carbonate, St. Lawrence Formation,T-PDC, Oneota Dolomite, Brazos Shale

Lodi Formation

Dresbach Sandstone

Precambrian "Red Beds"

Partridge Point Mbr

? ? ?

? ? ?

? ? ?

? ? ?

Norwood Mbr

Paxton Mbr

Lachine Mbr

Upper Mbr

Foster Fm

Pre

cam

bri

an

Figure Michigan.5 State of Michigan: Stratigraphic Column and Nomenclature.

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Upper Peninsula Sedimentary RocksKnowledge of bedrock geology in Michigans UpperPeninsula is less dependent on borehole data, since thereare many more outcrops (Figure Michigan.8) to help definethe rock types and their distribution. There are, however,many relatively shallow boreholes and some cores that havebeen drilled throughout the Upper Peninsula, especially inareas of mineral exploration. The Eastern Upper Peninsulais part of the Michigan Basin and contains the older stratathat also occur deeper in the center of the Basin. Many out-crops and shallow boreholes show the bedrock in the UpperPeninsula to consist of Cambrian through Upper Silurian

age rocks. Many of these units are quite similar to forma-tions known from the deep subsurface in the LowerPeninsula.

Cambrian sandstones of the Munising Formation under-lie much of the Eastern Upper Peninsula and outcrop alongthe Lake Superior shore, especially at the famous PicturedRocks National Lakeshore (Figures Michigan.9 andMichigan.10). The cross-bedded sandstones are colorfullystained by mineral oxides of copper, iron, manganese, andother metal cations that have precipitated from ground-water flowing through the porous sandstone. The MunisingFormation is thought to be slightly younger than theMt. Simon Cambrian sandstone in the Lower Peninsula.The Au Train Formation, overlying the Munising Formation,is a glauconitic or dolomitic sandstone that completes theSauk Megasequence in the Upper Peninsula.

Tippecanoe Megasequence strata are nearly the same inthe Upper Peninsula as seen in the Lower Peninsula, exceptmost units are thinner due to their location near the Basinmargin where less subsidence allowed for less depositionalspace to accumulate sediments. Unconformities at Basinmargins also have more impact on the preserved stratigraphicrecord. During regional sea level falls, erosion at Basin mar-gins begins sooner and lasts longer than in the Basin interi-ors. During the subsequent sea level rise, deposition occurslast at the Basin margins. The St. Peter Sandstone, a trans-gressive sandstone unit deposited after the major regionalunconformity at the Sauk-Tippecanoe Megasequenceboundary, is over 1,000 feet thick (305 meters) in the centerof the Basin (Lower Peninsula), but does not occur anywherein the Upper Peninsula.

An unusual geologic formation called the MackinacBreccia caps the Tippecanoe Megasequence in the Upper


Figure Michigan.7 Rocky Beach outcrop of Traverse Limestonewith large glacial erratic boulders. U.S. Highway 31, roadside parknorth of Charlevoix, MI.

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RELATIVE SEA LEVEL

present

higher lower

TEJAS

ZUNI

ABSAROKA

KASKASKIA

TIPPECANOE

SAUK

Quaternary

Tertiary

Cretaceous

Jurassic

Triassic

Permian

Pennsylvanian

Mississippian

Devonian

Silurian

Ordovician

Cambrian

Precambrian400 m 200 m -200 m

Nondepositional Hiatuses Deposition

Figure Michigan.6 Cratonic sea level megasequences. Bluearea represents relative global area of continental exposure above sealevel at different geologic times.

Adap

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Figure Michigan.8 Quarry with Engadine Dolomite at the out-crop of the Niagaran escarpment, State Rd. 123, Mackinac Co., MI.

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Peninsula. The Mackinac Breccia is a collapse megabrec-cia resulting from the dissolution of Upper Silurian saltsalong the northern margin of the Basin, principally in theregion of the Straits of Mackinac. It contains randomlyoriented blocks of Upper Silurian and Lower Devoniancarbonate formations that were turned to rubble whenevaporite deposits beneath them dissolved by fresh waterinflux during times of sea level drawdown. There are nodeposits younger than Lower Devonian in the UpperPeninsula.

Upper Peninsula Precambrian RocksAbundant bedrock exposures occur in the western part of theUpper Peninsula due to thin or absent glacial drift and exten-sive mining operations. Rocks here are not part of theMichigan Basin, but instead are related to the Lake SuperiorBasin and several terranes and structural complexes affixed tothe southern margin of the Canadian Shield. The oldest for-mations are middle Precambrian (2.5 billion years old)metavolcanic and metasedimentary rocks in the MarquetteTrough. This area also contains large deposits of banded

iron formations that have been extensively mined. TheMona Schist is among the oldest of these formations. Itcontains large areas of basalt with obvious pillow lava pat-terns (Figure Michigan.11) that have now been altered togreenstone through metamorphic processes. Slightly youngermetasedimentary rocks include cross-bedded sandstones ofthe Mesnard Quartzite and stromatolite-rich, shallow watercarbonates of the Kona Dolomite. The Banded IronFormations, most notably the Negaunee Iron Formation, atabout 2.1 billion years old are even younger. Less significantiron formations, metavolcanics, metasediments, and intrusiveigneous rocks are distributed throughout the region andrange in age from 1.6 to 2.0 billion years old.

Late Precambrian (Keweenawan age) volcanic and vol-caniclastic sedimentary rocks occur in the far western part ofthe Upper Peninsula, especially on the Keweenaw Peninsula.The Copper Harbor Conglomerate is a volcaniclastic unitderived from weathered and eroded rubble interbeddedwith basalt flows of the Portage Lake Lavas. Vast nativecopper deposits were precipitated in intergranular spacein these conglomerates or in amygdaloidal vesicles within


Figure Michigan.9 Pictured Rocks National Lakeshore: LakeSuperior Shoreline, Chapel Rock member of the Munising Formation.

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Figure Michigan.10 Miners Castle is a developing sea stackalong the Lake Superior shoreline east of Munising, Michigan. Notethe sea cave near the waterline that has eroded through the peninsulato the other side, beginning the formation of a sea arch. The under-cut, notched cliff face is due to two conditions. First, the notched sec-tion was situated right at lake level, and subjected to wave pounding,prior to the recent drop of the Lake Superior water level. Second, theChapel Rock sandstone, lower in the section at the notch, is lessresistant than the overlying Miners Castle sandstone (both units aremembers of the Munising Formation). The columns remaining on topwere formed as sea stacks on a wave-cut platform during an earlierand higher glacial lake stage.

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the basalt. These native copper deposits were extensivelymined in the nineteenth and early twentieth centuries.Disseminated copper also occurs in commercial amounts inthe black, petroliferous Nonesuch Shale.

Michigan.3Quaternary GeologyFormation of the Great Lakes BasinsEpisodic glaciation was the major process responsible forcreating the Great Lakes basins (Figure Michigan.12); how-ever, bedrock (type and distribution), regional structure andpaleo-drainage patterns have all influenced the present-dayconfiguration.

The watershed can be divided into two regions (FigureMichigan.13). The northern upland region (the CanadianShield) is underlain by Precambrian granites, gneisses, andmetavolcanic and metasedimentary rocks. These rocks, inthe Lake Superior area, were folded during the PenokeanOrogeny (middle Precambrian time) into a northeastsouthwest-trending regional syncline. During the Quaternary,this structural trough helped funnel advancing glacial icesouthwestward, which scoured and deepened the synclinalbasin even more, eventually forming Lake Superior.

The northern upland region also includes the GeorgianBay basin (eastern portion of Lake Huron) and part of theLake Ontario basin. The underlying syncline of the LakeSuperior area is not present in these areas. Only the regionaljoint pattern, northeastsouthwest- and northwestsoutheast-trending conjugate joints, provides any bedrockinfluence, sometimes producing straight erosional linea-ments in an otherwise random, glacially eroded pattern(Figure Michigan.14). Topography throughout the northernregion is dominated by exposed Precambrian bedrock that hasbeen scoured and sculpted by repeated glacial events. Somethin, discontinuous glacial sediments are only locally present.

The southern lowland region (the Michigan Basin) isunderlain by relatively soft, Paleozoic sedimentary rocks.These rocks all dip toward the center of the state of Michiganinto the structural basin. These rock layers appear as aseries of stacked bowls with their truncated edges forming acircular pattern encompassing and forming the state ofMichigan (much like a bulls-eye). This region includes theLake Erie, the Lake Michigan, the western portion of theLake Huron, and a portion of the Lake Ontario basins.Glacial erosion has scoured out these lake basins followingthe circular, structural pattern where the Paleozoic rockscrop out at the surface around the Michigan Basin. Here, thepattern is much more controlled and better developed thanthat formed by glacial erosion on the Canadian Shield gran-ite, gneisses, and metasedimentary rocks. This difference isparticularly apparent when observing the semi-circular shapeof the western portion of Lake Huron carved out of thePaleozoic rocks, in comparison to the more random shape ofthe eastern portion (Georgian Bay) glacially scoured from thePrecambrian Shield (see Figure Michigan.14). This semi-circular pattern continues through the western end of LakeErie along the Bass Islands, and is reflected in the curvilinearshape of Lake Michigan to the west and Straits of Mackinacto the north. The Great Lakes basins simply conform to theoutcrop pattern of the soft limestones and shales of UpperSilurian, Ordovician, and Devonian age.

The Great Lakes watershed was subjected to long-termsubaerial erosion prior to Quaternary glacial events.Glacial ice was then channeled through the region by thispre-existing drainage system. Relatively weak bedrock,already exploited by valleys of the paleo-drainage system,was increasingly scoured and eroded, thereby exertingone more control upon the formation of the present-daylandscape.

Even the Lake Superior Basin, which is located entirelywithin the Canadian Shield and was initially developedalong the length of a structural syncline, owes much of itscurrent shape to the bedrock. Rocks within the synclineincluded Precambrian sandstones and slightly metamor-phosed sedimentary rocks that are less resistant to glacialerosion than the underlying volcanic rocks. Glacial scour-ing and erosion removed these weak rocks, greatly accentu-ating the Basin initially formed by the syncline.

Just the opposite holds true for the islands and peninsulasthroughout the Great Lakes. More resistant rock typesunderlie these areas. Many examples can be observed.Resistant Silurian dolomite forms the Door and GardenPeninsulas separating Green Bay from Lake Michigan. TheNiagaran Series of resistant limestones and dolomites ofSilurian age occurring along the northern shore of LakeMichigan form the islands separating the North Channel andGeorgian Bay from Lake Huron, form the Bruce Peninsula,and can be traced eastward as a long escarpment which theNiagara River flows over at Niagara Falls. ResistantPrecambrian Portage Lake Volcanics form the backbone ofthe Keweenaw Peninsula and Isle Royale in Lake Superiorwithin the northern section of the Great Lakes watershed.Glacial scouring varies considerably from lake to lake


Figure Michigan.11 Pillow Lavas in the Upper Peninsula ofMichigan. These pillows are approximately 2 feet long and indicatedeposition below water. They have subsequently been eroded by over-riding glaciers that have polished, striated, and plucked the exposedsurface.

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Michigan.3 Quaternary Geology 9

KEWEENAW

HOUGHTON

ONTONAGON BARAGA

MARQUETTEGOGEBIC

CHIPPEWA

LUCE

ALGER

SCHOOLCRAFT

IRON

DICKINSON

MACKINAC

DELTA

MENOMINEE

EMMET

CHEBOYGAN

PRESQUE ISLE

CHARLEVOIX

ALPENA

MONTMORENCY

LEELANAU

OTSEGO

ANTRIM

GRAND TRAVERSEALCONAOSCODACRAWFORDKALKASKA

BENZIE

IOSCOOGEMAWROSCOMMONMANISTEE MISSAUKEEWEXFORD

ARENAC

MASON GLADWINCLAREOSCEOLALAKE

HURON

BAY

MIDLANDISABELLAOCEANA MECOSTA

NEWAYGO

TUSCOLASANILAC

SAGINAW

GRATIOTMUSKEGON MONTCALM

LAPEER

KENT GENESEE

ST CLAIR

OTTAWA

SHIAWASSEE

CLINTONIONIA

MACOMB

OAKLAND

LIVINGSTONINGHAMEATONBARRYALLEGAN

WAYNE

WASHTENAWJACKSONCALHOUNKALAMAZOOVAN BUREN

BERRIENMONROE

LENAWEEHILLSDALEBRANCHST JOSEPHCASS

Peat and muck

Postglacial alluvium

Dune sand

Lacustrine clay and silt

Lacustrine sand and gravel

Glacial outwash sand and gravel and postglacial alluvium

Ice-contact outwash sand and gravel

Fine-textured glacial till

End moraines of fine-textured till

Medium-textured glacial till

End moraines of medium-textured till

Coarse-textured glacial till

End moraines of coarse-textured till

Thin to discontinuous glacial till over bedrock

Artificial fill

Exposed bedrock surfaces

Water

QUATERNARY GEOLOGY OF MICHIGAN

Drumlins

Eskers

Shorelines

Sinkholes

Striations/Grooves

0 20 40 MilesDate: 11/12/99N

MichiganMICHIGAN DEPARTMENT OF NATURAL RESOURCESLAND AND MINERALS SERVICES DIVISIONRESOURCE MAPPING AND AERIAL PHOTOGRAPHY

Michigan Resource Information SystemPart 609, Resource Inventory, of the Natural Resources andEnvironmental Protection Act, 1994 PA 451, as amended.

Automated from "Quaternary Geology of Michigan", 1982, 1:500,000 scale, which was compiledby W. R. Farrand, University of Michigan and the Michigan Department of Environmental Quality,Geological Survey Division.

SOURCE

RMAP

1982 QUATERNARY GEOLOGY OF MICHIGAN

Figure Michigan.12 State of Michigan: Quaternary Geology.

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(Figure Michigan.15). Lake Superior, the deepest of thefive lakes, is 1,333 feet (406 meters) deep. Lake Erie, theshallowest, is only 210 feet (64 meters) deep. The floorsof Lakes Superior, Huron, and the northern portion ofMichigan tend to be somewhat irregular.

Glacial sediments, often greater than 165 feet (50 meters)thick, and in places over 1,150 feet (350 meters) thick, blan-ket the region. Broad, low, glacial moraines and a fewPaleozoic bedrock escarpments provide moderate relief.

Quaternary glacial sediments also occur in the basins, oftenexceeding 330 feet (100 meters) in thickness. Portions ofLake Superior contain glacial sediments greater than 850 feet(250 meters) thick. These glacial sediments indicate that thepresent-day Great Lakes Basins are the product of both gla-cial erosion and post-glacial deposition.

Glacial EventsThe glacial history of the Michigan Basin is very complex.Six major ice sheets advanced across the Michigan regionprobably beginning as early as 2.4 million years ago (2.4 Ma).The oldest advances, previously called the Kansan andNebraskan events, must have advanced across Michiganbecause sediments from these events are found much farthersouth across Ohio, Indiana, Illinois, and into Kansas andNebraska. Geologists now know that these events were muchmore numerous and complex than originally thought, andthe terms Kansan and Nebraskan are no longer used.

The last two events, the Illinoian and Wisconsinan events,are much better documented and understood, and this termi-nology is still in use. Illinoian events are inferred fromdeposits found primarily in Illinois. Glacial sediments in theMichigan Basin once thought to be Illinoian, are nowthought to actually be younger Wisconsinan deposits.Currently, indisputable and direct evidence of Illinoian gla-cial events in the Michigan Basin has yet to be discovered.Warm conditions much like today, in a period 125179 thou-sand years ago known as the Sangamon interglaciation, existedbetween the Illinoian and Wisconsinan glacial events.


Area ofdeposition

and erosionscouringArea of

Area ofnon-glaciation

Figure Michigan.13 The Great Lakes Watershed: GlacialErosion vs. Deposition.

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Figure Michigan.14 The Great Lakes Watershed: Patterns of Landscape Development.

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The last glacial episode, the Wisconsinan advance of theLaurentide Ice Sheet, is well documented throughoutthe Michigan Basin. Three separate sublobes of this lastglacial ice sheet advanced and retreated across the Basin(the Michigan, Saginaw, and Erie Lobes) (see FigureMichigan.12). Although no compelling evidence exists, itis thought that advance and retreat of these sublobes was notalways synchronous.

Wisconsinan glaciation began sometime between 65 and79 thousand years ago (6579 ka). Glacial ice first invadedthe eastern section of the Great Lakes watershed where theice margin oscillated until approximately 25 ka. During thistime, a boreal forest-tundra environment covered most ofthe western portion of the watershed (the Michigan Basin).After 25 ka, the ice sheet advanced from both the north andthe east, overriding the western forest-tundra landscape, andcovered the entire watershed. Ice eventually reached theOhio River to the south and northern Wisconsin and east-central Minnesota to the west. The ice front fluctuated therefor nearly 4,000 years. After 18 ka, the ice margin began toretreat, but experienced a series of re-advances about 15.5,13.0, 11.8, and 10.0 ka (Figure Michigan.16). Ice finally con-tinued its retreat about 10.0 ka, and the watershed was com-pletely ice-free by 9.0 ka.

Glacial LakesLarge, glacial, ice-margin lakes (proglacial lakes) were devel-oped during each retreat of the ice sheet. These lakes filled

the newly scoured Great Lakes basins. The northern marginof each lake was established by the southern edge of the gla-cial ice sheet. The extent and elevation of these lakes variedas outlets were blocked by ice or uplifted by isostaticrebound. New outlets formed as rising lake levels foundnew low spots through ridgelines. Channels were erodedand downcut or melting ice re-opened old channels.Occasionally, catastrophic influx of water from neighboring


?

?

?

??

?

?

KEY

Advance of 15.5 kaAdvance of 13 kaAdvance of 11.8 kaAdvance of 10 ka

Michigan

LakeSuperior

Lake

Mic

higa

n

Lake Huron

Lake E

rie

Lake Ontario

Figure Michigan.16 Limits of Wisconsinan Ice Re-advances.

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Lake Michigan

Lake Ontario

Lake St. Clair

Niagara River

St. Marys River St. Clair River Detroit River

Niagara Falls

St. Lawrence RiverLakeSuperior

LakeHuron

Lake Erie

Elevation183.2 m601.1 ft





Depth406 m

1,333 ft

Depth229 m750 ft

Depth281 m923 ft

Depth64 m210 ft

Depth244 m802 ft

Sea Level

Totals

Kilometres

Miles

2,011

1,249

610 97 359 143 380 56 242 124

379 60 223 89 239 35 150 77

Distance

Figure Michigan.15 Profile of the Great Lakes.

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Uni

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Stat

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Eng

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glacial lakes to the west affected the lake levels. This series ofglacial lakes left a legacy of lake sediments, abandoned spill-ways and channels, wave-cut cliffs, beach ridges, deltas, andabandoned shorelines. Some of those old shorelines can stillbe traced from one lake basin to another.

The history of the proglacial lakes that occupied theGreat Lakes watershed is summarized in Figures Michigan.17and Michigan.18ad. Fed by glacial meltwater during iceretreats, these lakes expanded, often to the point where theymerged with one another. Conversely, the lakes contractedas water levels fell due to the opening of new drainagechannels, or as glacial ice once again advanced through thevarious basins of the watershed.

The Lake Superior Basin remained ice covered untilapproximately 12 ka. Then, as glacial ice retreated from theBasin, a series of relatively small proglacial lakes formed.These lakes expanded and merged with lakes in theMichigan and Huron Basins to eventually form glacialLakes Nipissing and Algoma.

The Lake Michigan Basin became ice free early in its his-tory. Ice retreated from the southern portion of the basinabout 16 ka, and the first of a series of proglacial lakesformed. This early lake, termed Lake Chicago, expanded andcontracted in conjunction with a series of glacial retreats andre-advances. Glacial Lake Algonquin formed approximately

12 ka as ice retreated, the Straits of Mackinac opened, andLake Chicago (Kirkfield Stage) expanded and merged withwaters occupying the Huron Basin. Eventually, with contin-ued ice retreat, waters in the Lake Michigan Basin joinedthose of Superior and Huron to form glacial Lakes Nipissingand Algoma.

High rates of bluff erosion, development of strong cliffs,and formation of very large sand dunes occurred in associa-tion with the Lake Nipissing Great Lakes stage (see FigureMichigan.18d). Tower Hill, in Warren Dunes State Parksouth of Benton Harbor, and Mt. McSuba, just east ofCharlevoix, are two examples of these large Lake Nipissingdune fields. Sleeping Bear Dune, north of Frankfort,Michigan, is partially glacial moraine and outwash depositscovered by windblown sand dunes formed during this sametime.

The Lake Huron Basin (particularly the southern por-tion of the basin), much like the Lake Michigan Basin,became ice-free early in its history. There were at leastthirteen different proglacial lakes that occupied the basinbefore merging into glacial Lake Algonquin. These earlylakes, for the most part, drained westward across the centerof the state of Michigan. This drainage pattern eventuallydeveloped into the present-day Grand River Valley system.Huron Basin waters expanded as the northern portion of


SUPERIOR MICHIGAN HURON ERIEDATE GLACIAL EVENT ONTARIOYEARS BEFORE

PRESENT

Port Huron (Mankato)

Algonquin

Kirkfield

Calumet

Glenwood II

640

Glenwood I

640

246

246

573580580

595

595 Stanley 190

605

605

620

640

675660 (Brief )

690- 680738

780760800

695

710, 700, 695

565 (?)

620 Lundy

Early Lake Ontario

Iroqouis

Ice

Ice

Ice

Ice

Lake

Lake

Small Lake

Vauxem 2

?

Lake Ontario

Grassmere

Lowest WarrenWayneWarren

Whittlesey

Cary-Port Huron Low Water Stage

602

3,000

4,000

9,500

11,500 Valders Maximum

Two Creeks

Lake Border Moraine

Tinley-Defiance Moraine

Valparaiso Mor.

Lake?

Lakes

Keweenaw

IceDuluth

Post Duluth

Sub-Minong

Algona

Nipissing

Chippewa

Post Algonquin Upper Group

Ice

IceIce

Ice

Maumee IIIArkona

Lowest Arkona IISaginaw 695

Maumee IIMaumee I

Ice

11,850

13,000

13,300

Ice

Early L. Chicago

EarlySaginaw

Ice

Ice

Early AlgonquinToleston 605

605605 Early Algonquin Ice

Early Lake Erie

Lake Erie 573

Figure Michigan.17 Chart: Evolution of Glacial Lakes throughout the Great Lakes Basins.

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Esc

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the basin became ice-free, and merged with waters in theLake Michigan and Lake Superior Basins to form glacialLakes Nipissing and Algoma.

The same thirteen proglacial lakes that occupied the LakeHuron Basin early in its history also occupied the Lake ErieBasin. Beginning about 12 ka, the Huron and Erie Basinsdeveloped separately as ice retreat and isostatic reboundcaused new drainage patterns to develop. Waters from theHuron Basin merged westward with those in the Michiganand Superior Basins to form Lake Algonquin. The presenceof glacial Lake Algonquin is evidenced today by numerouswave-cut platforms and other erosional coastal features cutinto bedrock, now observed high up along much of the pres-ent-day shoreline (Figure Michigan.19). Waters in the Erie

Basin fell to a lower level as new eastward drainage developedfor that basin, forming the early stages of modern Lake Erie.

Like the Lake Superior Basin, most of the Lake OntarioBasin remained ice covered throughout its early history.Only the southeastern portion of the basin was ice free after13.3 ka, and was occupied by a series of small proglaciallakes. All these lakes drained eastward, first along the glacialice front, and later through New York State into theMohawk River Valley. The early stages of glacial Lake Erie(12 ka) drained eastward into the Ontario Basin where thesewaters formed glacial Lake Iroquois. When eastwarddrainage through the present-day St. Lawrence Riveropened, Lake Iroquois drained to a lower level, forming theearly stages of modern-day Lake Ontario.


Ice

Lake Ontario

Lake Hough

Lake Stanley

Lake Chippewa

Minon

g-

Houg

hton

0 200 km

Cham

plain

Sea

Lake Er

ie

Laurentide Ice Sheet

LakeChicago

LakeWarren

0 200 km

Ice

Lake Duluth

Lake Ontario

0 200 km

Cham

pl

ain Se

a

Lake

Algonquin

Lake E

rie

0 200 km

Lake Ontario

St.

Law

re

nce R

iver

Nipissing Great Lakes

Lake Er

ie

13,000 years ago

9,500 years ago 6,000 years ago

11,500 years ago

a

c

b

d

Figure Michigan.18ad Glacial Lake Stages: Ice Advances and Retreats.

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Figure Michigan.19 Profile of Mackinac Island showing Glacial Lakes Algonquin and Nipissing wave-cut cliffs and platforms.

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Glacial LandscapesGlacial landscapes in Michigan result from two opposingprocesses: deposition and erosion. Thick deposits of glacialdebris capped by associated depositional landforms blanketthe entire Lower Peninsula of Michigan and the easternportion of the Upper Peninsula. Only the western portionof Michigans Upper Peninsula displays an erosional,Precambrian-aged, bedrock landscape that is scoured clean.Northward, the Canadian Shield is deeply eroded andscoured into the Precambrian bedrock with only a scatter-ing of depositional features.

Erosional Glacial Landforms. Despite the blanket of gla-cial sediments covering most of the Michigan Basin, thereare scattered outcrops displaying the erosional power ofglacial ice that moved through the region. Glacial groovesare displayed on Late Silurian dolomite bedrock of the BassIsland Group where it crops out along the west side ofSouth Bass Island in Lake Erie near Put-in-Bay. One of themost spectacular, and perhaps the best known, glaciallygrooved surfaces in the Great Lakes Region is found onKellys Island, off Marblehead Peninsula in Lake Erie.

Glacial erratics (of Precambrian age), carried by theglacial ice southward into Michigan from the CanadianShield, are found in glacial deposits throughout the state.Boulders of Banded Iron Formation (BIF) and pieces ofnative copper from the Upper Peninsula are occasionallyfound in Lower Michigan. Although fairly rare, they areeasily spotted because they are so distinctive and tend tostand out from the drab sands and gravels. More commonly,rounded pebbles of gray and pink granite, derived fromthe Canadian Shield, are found in the gravels depositedthroughout the Michigan Basin (Figure Michigan.20).

Depositional Glacial Landforms Figure Michigan.21shows the locations of geologic features discussed in the fol-lowing sections. Most of the Michigan Basin is blanketedby glacial deposition in the form of diamictons (formerly


Figure Michigan.20 Erratic pebbles in typical southwesternMichigan gravel (note gray and pink granites, quartz pebbles.)

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termed glacial tills) and glacial outwash. Landforms,such as drumlins and moraine systems, are composed ofdiamictons deposited directly from the glacial ice.Diamictons are unsorted and unstratified deposits com-posed of a heterogeneous mixture of materials in all shapesand sizes.

Outwash, on the other hand, is a very general termapplied to sorted and stratified deposits laid down by glacialmeltwaters. Depositional glacial landforms such as kames,kame terraces, eskers, and ice-channel fillings are indica-tive of ice-contact and outwash deposition. Landforms suchas outwash plains and valley trains, pitted outwash plains,kettles, and kettle lakes usually indicate deposition near theice but farther removed from the immediate ice front(Figure Michigan.22).

Diamicton and DrumlinsNumerous, well developed drumlins can be observed alongboth sides of Grand Traverse Bay. Drumlins in Charlevoixand Antrim Counties, just north of Torch Lake, trendsouth-southwest, indicating the direction of the ice move-ment. U.S. Route 31 follows the length of two drumlinsbetween Torch Lake and Charlevoix. The exposed interiorof these drumlins is composed of unsorted, unstratified clayand boulder diamicton (till). Another drumlin field is situ-ated along U.S. Route 2 between Harris and Waucedah,Michigan, in the Upper Peninsula. Small drumlins are alsolocated in Barry County, 20 miles west of Kalamazoo, insouthwestern Michigan.

Moraines. Moraine systems are the most prominent land-scape features across Lower Michigan. Three major ice lobesadvanced across Michigan during the Wisconsinan glacia-tion. These advancing ice masses took on lobate forms, fan-ning outward in radial patterns along their fronts as glacialice was channeled through the pre-existing Great LakesBasins. The Michigan Lobe advanced southward through theLake Michigan Basin. The Saginaw Lobe advanced south-westward as it was channeled through the Saginaw Bay area.The Erie Lobe advanced westward as it was funneledthrough the Lake Erie Basin (see Figure Michigan.12).These three lobes advanced into northern Illinois, Indiana,and Ohio, developing a pronounced terminal moraine (theCary Border) approximately 16 ka. The state of Michiganwas covered by thousands of feet of ice during this time.Retreat from this position lasted until about 13.513.2 ka,depositing a series of recessional moraines of Cary age.The prominent Valparaiso Moraine and Lake BorderMoraine that parallel the Lake Michigan coastline throughwestern Michigan, Indiana, Illinois, and Wisconsin formedduring this time.

These moraines took on the form of rolling ridges ofdiamicton and poorly sorted sediments laid down as ice-contact deposits, grading into sloping wedges of outwashdeposits farther away from the ice front (Figure Michigan.23).Minor re-advances interrupted the retreat, often smearing outand re-working the just-deposited recessional moraine system


as the advancing ice moved over it. This can be seen in onecase where thin, weathered, till deposits overlay outwash sedi-ments in the Whittaker-Gooding Pit off Cherry Hill Road,just south of Dixboro, east of Ann Arbor.

Two major, interlobate moraines formed, one betweenthe Michigan and Saginaw lobes, and one between theSaginaw and Erie lobes. The first extends north-souththrough the center of the state. The other follows the axisof the thumb (east of Saginaw Bay). These areas containmuch sand and gravel in the form of kames and extensiveoutwash plains (called the Sand Barrens) laid down by melt-water deposition.


1. Mt. Baldy, Warren Dunes State Park area2. Sleeping Bear Dune State Park (near Frankfort)3. Mt. McSuba (near Charlevoix)4. Drumlins a. Charlevoix and Antrim Counties b. Torch Lake area c. Harris and Waucedah areas d. Barry County area5. Eskers a. Blue Ridge EskerU.S. 127 (south/southeast of Jackson) b. Mason EskarU.S. 127 (near Dewitt) c. EskarBarry County (Figure 24) 6. Kames a. Stony Creek Park (near Rochester) b. Oxford area c. Irish Hills, Walter J. Hayes State Park (near Jackson) d. Route 32 area (near Lacine, west of Alpena)7. Valley Train Sedimentation (Mancelona to Kalkaska)8. Castle Rock (near St. Ignace)9. Mackinac Island10. Beach ridges (north of Port Huron)11. Beach groins12. Hooked spits a. Tawas Point b. Hamlin Lake13. Mid-bay and bay mouth bars a. Crystal Lake b. Herring Lakes14. Karst Topography a. Sunken Lake, Rainy Lake, Fletcher County Park area (near Alpena, Leer, and Posen) b. Monroe Area c. Presque Isle15. Tunnel Valley, Kalamazoo River Valley (near Galesburg)16. Deltas a. St. Claire River b. Rouge River, Detroit c. Huron River (near Yipsilanti) d. Grand River (near Allendale)17. Scoured LakesBurt, Mullet, and Black Lakes18. Significant Oil Fields a. Saginaw Field b. Muskegon Field c. Mt. Pleasant Field d. Bloomingdale Fields e. Crystal Field f. Albion-Scipio Trend19. Kettle Lakes

Figure Michigan.21 Location of Geologic Sites

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The Port Huron Border Moraine, immediately adjacentto the Saginaw Bay shoreline, is the terminal moraine ofthe ice that began re-advancing approximately 13.2 ka.Intermittent retreat from this position quickly resumed,lasting until 11.811.5 ka. This period of retreat is termedthe Two Creeks interstadial.

The last major advance of Wisconsinan glacial iceoccurred 11.8 ka (termed the Valders stadial). Ice, advanc-ing from the north through the Lake Michigan Basin,picked up large quantities of red silt and clay from the LakeSuperior Basin (evidence that the Lake Superior Basin musthave been a proglacial lake prior to this event) and from thePrecambrian iron formations of the Upper Peninsula. Theresulting Valders-aged moraines and diamicton deposits, allof which lay north of the older Port Huron Border, are adistinctive red color as a result. This Valders ice advance isalso responsible for the formation of the drumlins locatedin Leelanau and Charlevoix counties.

Outwash, Ice-channel Deposits, and Eskers. Sinuous,elongate ridges of outwash materials, flanked by slopes com-

posed of ice-contact sediments, result when glacial debris islaid down within ice-bounded channels. Three excellentexamples of such ridges occur in central Michigan. The firstis the Blue Ridge Esker that is cut by U.S. 127 about 6.5 milessouth-southeast of Jackson, Michigan. The second example isthe Mason Esker, located just east of U.S. 127 and extendingfrom Mason to DeWitt, in Ingham County. Barry County ishome to the third example. Here, a large esker is observedassociated with a field of kames (Figure Michigan.24).

Kames. Kames are hills of outwash flanked by slopes ofice-contact materials. They initially form in low areas betweenice blocks, or holes within the glacier. Meltwater depositsflood into these depressions, and ice-contact materials rapidlyaccumulate around the edges. When the ice melts, the walls ofthese deposits collapse, leaving behind steeply sloping hills.Groups of Kames can be found in Stony Creek Park nearRochester, the gravel hills near Oxford, and the Irish Hillsnear Walter J. Hayes State Park southeast of Jackson,Michigan. Isolated kames occur along Michigan Route 32near Lachine, west of Alpena, and many more can be foundscattered throughout the state. Kames are also associated withthe previously mentioned large esker in Barry County (seeFigure Michigan.24).

Proglacial Outwash and Valley Trains. Proglacial out-wash is deposited as a sloping, apron-like fan of meltwater-laid sediments out in front of an ice-contact recessionalmoraine being deposited along the ice lobe. Most reces-sional moraines throughout Michigan occur in associationwith proglacial outwash aprons that were initially depositedaway from the glacial margin. The term valley train isapplied to these sloping proglacial aprons when they areconfined within valley walls. Good examples of valley trainscan be observed in the valley extending from Mancelona toKalkaska, Michigan.

Pitted Outwash, Kettles, and Kettle Lakes. Outwash sed-iments are frequently laid down around separate blocks ofstagnant ice left in front of the retreating ice sheet. Largedepressions in the outwash plain result when these ice blocksfinally melt. These depressions are termed kettle holes,and the resulting outwash fan, pock-marked by a number ofkettle holes, is termed a pitted outwash plain. Kettle holes


Figure Michigan.24 Esker: Barry County Michigan. The esker is seen as a large ridge (note cars sitting on esker, for scale). Kames, depositedclose to the ice front, can be observed surrounding the esker in the left portion of the photo.

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Figure Michigan.23 Outwash in Barry County gravel pit (nearHastings).

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become kettle lakes when they fill with water. Most ofthe numerous, small, inland lakes throughout Michigan arekettle lakes, and are associated with pitted outwash plains.

Michigan.4Modern-Day GeologicProcessesThe geologic history of the Michigan Basin does not endwith the retreat of the most recent glaciers. Rather, land-scape development is an evolutionary, ongoing process.For example, several distinct types of shorelines exist alongthe Great Lakes.

Bedrock cliffs are most common along the shores ofLakes Superior and Huron. Cliffs 1,3122,625 feet(400800 meters) in height are common along the northshore of Lake Superior. Beaches of sand and gravel arecommon along the southern shore. Limestone bedrock andgravel form much of the Lake Huron shoreline east of theMackinac Bridge. High dolomite cliffs are common alongthe Lake Huron and Lake Michigan shorelines whereverthey intersect the Niagaran Series of rocks. The easternmargin of the Door Peninsula, the Garden, Bruce, andPresque Isle Peninsulas, and the western margin ofManitoulin Island are examples of such areas. Rocky head-lands and small pocket beaches composed of rounded lime-stone gravel and sand are found along these shores. Bluffscut into glacial sediments are especially prominent alongthe southeastern shore of Lake Huron, the central sectionof Lake Michigan, and the shores of Lake Erie. Many of theLake Erie shores are low and marshy.

Erosional ShorelinesMackinac Island continues to be, after more than a century,a favorite tourist destination in Michigan. The well devel-oped shoreline features of this island, as they relate to thevarious glacial lake stages, can easily be observed fromthe Mackinaw Straits Bridge (see Figure Michigan.19). TheAlgonquin wave-cut cliff and terrace dominate the upperportion of the island. The Nipissing wave-cut cliff and ter-race dominate the lower portion. More than 14 differentbeach ridges are situated between the Algonquin andNipissing terraces and can be explored all across the island.Associated with these two major wave-cut cliffs are a num-ber of erosional shoreline landforms. Arches, sea stacks,and caves have all been eroded from the weak MackinacBreccia bedrock. The best-known sea arch on the island isArch Rock, formed during Glacial Lake Nipissing time (seeFigure Michigan.25). Sugar Loaf, a prominent sea stack, islocated 300 feet (91 meters) east of the Algonquin wave-cutcliff at Point Lookout. Skull Cave is cut into a second stackformed by Glacial Lake Algonquin.

Sea cliffs and sea stacks can be observed at Miners Castle(see Figure Michigan.10) in the Pictured Rocks area along

Michigan.4 Modern-Day Geologic Processes 17

Lake Superior east of Munising. Also, sea cliffs cut intoMississippian age sandstones are visible at Pointe AuxBargues at the tip of Michigans thumb. Castle Rock, awave-cut stack of Mackinac Breccia, formed during GlacialLake Nipissing time, and can be observed along I-75 justnorth of St. Ignace (Figure Michigan.26).

Coastal bluffs, composed of glacial sediments, are subjectto erosion (Figure Michigan.27). Recent studies by Dr. AlanKehew and Dr. Ronald Chase of Western MichiganUniversity (United States Army Corps of Engineers grant) ofbluffs along Lake Michigans shoreline north of South Havenhave shown that bluffs are most susceptible to erosion duringperiods of high water. Low lake levels, as experienced duringrecent years, have greatly reduced the rate of slope failuresalong the Michigan coastline. Also, water content of bluffmaterials is a major controlling factor. Bluff stability isgreater, displaying little to no slope movement, during dryperiods when water tables are low. Pumping, to dewater bluffareas, helps increase slope stability, thereby reducing erosion.

Depositional ShorelinesSand Dunes. Beaches along the shores of the state ofMichigan are some of the best-developed, quartz-rich, sandbeaches in the world. Numerous areas of irregular sandaccumulations and dune fields occur well inland from cur-rent lake shorelines (Figure Michigan.28). These areas

Figure Michigan.25 Arch Rock, on Mackinac Island, was erodedfrom the Mackinac Breccia bedrock at the time of Glacial LakeAlgonquin. Modern Lake Huron, to the east, is visible in the back-ground through the arch.

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Grand Sable Dunes

Sleeping Bear DunesBenzie State Park

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From glacial Lake Saginaw

Dunes formed during early Glacial Lake Stages

Dunes formed during Lake Nipissing Stage

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Areas of extensive modern sand movement and foredune growth

Figure Michigan.28 Blown Sand and Dune Areas in Michigan.Dotted lines delineate areas of extensive modern-day sand movementand foredune growth. Black areas are older, high dunes related mostlyto Glacial Lake Nipissing. Dark green colored areas inland are stillolder dunes related to earlier, higher glacial lake levels. Note the dunefield southwest of Saginaw Bay which was created by Glacial LakeSaginaw.

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originated in conjunction with earlier proglacial lakesstanding at much higher elevations, and are generally theoldest dunes in the state of Michigan. The dune fielddeposited on the old lake plain of Glacial Lake Saginaw(southwest of present-day Saginaw Bay), in particular,

Figure Michigan.26 Castle Rock is a wave-cut sea stack locatedalong I-75 just north of St. Ignace, Michigan. It was cut from MackinacBreccia bedrock along the Glacial Lake Nipissing shoreline.

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Figure Michigan.27 Slumps along the Lake Michigan shoreline.Located about 4 miles north of South Haven, the view is southwardalong a part of the coast that is dominated by a sandy bluff with someclay layers on top. This slump structure is typical of bluffs withinterbedded clays and sands.

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stands out. These dunes can be observed along U.S.Highway 10 between Midland and Clare, Michigan.

Inland, high dunes are common along all the shorelinesthat ring the state of Michigan. Many of these high dunesare related to high-water levels of Early Glacial LakeNipissing (92.2 ka). Along the western side of the state,many of the inland, high dunes are related to the highstages of Glacial Lake Chicago that occupied the LakeMichigan Basin. Generally, these inland dunes are no olderthan about 13,000 years. They were stabilized by vegetationlong ago and are no longer sites of extensive dune growth.

Coastal dunes are younger than inland dunes, havingformed along the modern Great Lakes shoreline. They aregenerally less than 4,500 years old, and are mainly relatedto Late Glacial Lake Nipissing water levels. Coastal dunescan be divided into two categories. Foredune ridges arelow dunes (3050 feet [915 meters]) that are found closeto the waters edge. High dunes (greater than 100 feet[31 meters]) are generally found slightly farther inlandbehind the foredunes. High dunes may also be found at thewaters edge in a few instances. Some of the older highdunes may have been deposited on the tops of glacialmoraines and outwash deposits during periods of higherlake levels. These are termed perched dunes. Sleeping BearDune is just such a complex, standing 450 feet (137 meters)


above the current Lake Michigan water level (FigureMichigan.29). Grand Sable Dunes in the Upper Peninsulais another such system, standing 380 feet (116 meters)above Lake Superior. Perched dunes tend to be less thickthan other foredune types.

Foredunes are the youngest and most active dunes alongthe Michigan coast. Blowouts occur where dunes lack thestabilizing effects of vegetation. Sand is blown from thewindward side of the dune, up and over the crest, to bedeposited on the dunes lee side. (Figure Michigan.30).The dune is observed to march inland as this processcontinues. However, the coastal dunes eventually stabilizeas (1) they move away from the beach; (2) the source ofsand supply diminishes; (3) they become more protectedfrom the shore winds; (4) they encounter the fronts of theinland high dunes; and (5) vegetation takes hold and pro-vides stabilization. Unfortunately, in some areas, these sanddune systems are being threatened, not only by the flux ofnature, but more and more by human interference and lackof sound environmental stewardship.

Beach Ridges. Many beaches along Michigans shoresare marked by a series of recessional beach ridges. Theseridges, composed of gravel and coarse sands, were formedalong the shorelines by progressively dropping glacial lake

Michigan.4 Modern-Day Geologic Processes 19

Figure Michigan.29 Sleeping Bear Dunes (view northwardalong coast). This Pearched Dune (right portion of photo), 450 feetabove the current level of Lake Michigan, is partially stabilized by veg-etation. It sits atop an older glacial moraine (left portion of photo).Coarse cobble and pebble lag, weathered from the moraine by thewind, covers the moraines surface. The depression (center) is awind-generated blowout where sand is being scoured from the duneand blown inland.

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water levels. One set of well developed beach ridges can beobserved along the Lake Huron shoreline just north of PortHuron (Figure Michigan.31). Another example of beachridges can be observed at Sturgeon Point on Lake Huronjust north of Harrisville. Here, closely spaced lines of treesparallel the present-day shoreline. These tree lines reflectformer beach ridges, where sediments that favor treegrowth have accumulated.

Hooked Spits. Sands necessary for the growth of spitsand mid-bay and bay-mouth bars are supplied as beachdrift. This beach drift develops as longshore currentserode sands from the beaches they are moving along(Figure Michigan.32). Groins, built at 90 degrees to theshore out into the water, help prevent erosion by trappingbeach drift moving along the beach. Examples of suchgroins can be observed along the Lake Michigan shorelinenear Ludington, Michigan.

Sand bars and spits grow as beach drift, moving alonga shoreline, is deposited into an open embayment asit attempts to extend the beach. Waves, coming into theembayment from offshore, redistribute sediments nearthe end of the spit, carrying those materials farther into theembayment. This results in the formation of a hooked spit

Figure Michigan.30 Sands are constantly being blown inlandalong the east shore of Lake Michigan. Here, in Indiana Dunes StatePark, the lee-side of Mt. Baldy Sand Dune is encroaching upon thetrees. Note the angle of repose for the sand face is approximately35 degrees.

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Figure Michigan.33 The hooked spit at Tawas Point has a longand complex history. Waves from Lake Huron refract around thesouthern point of the spit, carrying sediment into the bay, and creatinga shoal behind the spit. The numerous lakes observed within the spitare the remnants of previous bay areas surrounded and cut off by thegrowing shoal and migrating spit.

as the end of the spit bends around toward the innershore of the embayment. Tawas Point, a hooked spit cur-rently evolving near Tawas City on Lake Huron, has a longand complex history (Figure Michigan.33). Nine separatehooks (points) and associated sub-bays have developed, andsubsequently, have been highly modified, as this largehooked spit continues to evolve.

Mid-Bay and Bay Mouth Bars. Waves, longshore currents,and wind action constantly re-shape the shorelines ofMichigan. The Upper and Lower Herring Lakes, located inBenzie County about 6 miles south of Frankfort, are goodexamples of such evolving shorelines (Figure Michigan.34).The two lakes lie within a U-shaped depression. This depres-sion is enclosed on the north, east, and south by the ManisteeMoraine, but was originally open toward the west as anembayment to Lake Michigan. During late Lake Algonquintime, mid-bay bars developed within the embayment. Thesebars isolated Upper Herring Lake in the mid-eastern portionof the embayment and another small basin in the very easternsection. This eastern basin was a short-lived lake and is nowfilled with sediment and vegetation.

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Figure Michigan.32 Northward view of groins along the LakeMichigan beach north of Manistee. The groins were originally used tocapture sand moving along the beach, but they now reside high inthe dune line due to the significant drop in lake levels during the last5 years. This is just one of many public beach access points alongthe coast.

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Figure Michigan.31 Recessional Beach Ridges, north of PortHuron, were formed by progressively dropping glacial lake levels in theLake Huron basin.

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The remaining western portion of the embaymentdrained during the early stages of Glacial Lake Nipissing,but during late Nipissing time, the embayment was onceagain flooded. During post-Nipissing times, the currentbay-mouth bar formed, isolating Lower Herring Lake inthe western portion of the embayment. Eventually, duringrecent times, low foredunes developed on top of this barand adjacent shorelines. Presently, the two Herring Lakesare isolated from Lake Michigan, being drained only bynarrow Herring Creek that cuts across the mid-bay andbay-mouth bar systems.

Crystal Lake, located immediately north of Frankfort,formed in a similar manner (Figure Michigan.35). Thearea originally occupied a topographic low, situatedbetween two east-west trending glacial moraines, andopened to Lake Michigan to the west. Development ofa bay-mouth bar isolated the embayment, and completeclosure was assured as dunes related to Glacial LakeNipissing covered the bar.

Hamlin Lake, in Ludington State Park on Big SablePoint (just north of Ludington, Michigan) is another prod-uct of shoreline evolution (Figure Michigan.36). Originally,five rivers entered the Lake Michigan Basin along this

portion of the coast. Sands carried into the lake by theserivers fed the growth of two large hooked spits, one fromthe north and one from the south. These spits formed twoarms that eventually enclosed Hamlin Lake, first as an openembayment, and finally as a separate, isolated lake. Highdunes related to Glacial Lake Nipissing formed atop thesespits, completing the enclosure.

Michigan.5Geology of Water ResourcesGroundwaterMichigan is very fortunate, mostly due to its glacial heritage,that high quality water resources abound throughout thestate. The majority of Michigans water wells tend to be shal-low, and can easily be pumped from surficial sands and gravelsdeposited by glaciers. Much of the grou

Documents

Geology of Michigan and the Great Lakes