Surficial Geologic Map of the 7.5 Minute Roanoke Quadrangle in Woodford County, IL 2015 Elena M. Topping, David H. Malone, and William E. Shields, Department of Geography-Geology, Illinois State University Abstract This study involved the construction of a geologic map of the Roanoke 7.5 minute quadrangle in Woodford County at a scale of 1:24,000. This area contained sections of the Eureka Moraine which is included in the Wisconsin glacier event. Methods used to construct this mapping area included using soil data from soil survey, well data, as well as LiDAR data. There were four major sediment formations that were found at the subsurface in the Roanoke quadrangle. The formations include the Cahokia Alluvium, the Wedron Group (Lemont Formation), The Henry Formation, and finally the Peoria formation. The Cahokia Alluvium consisted of interbedded sand, silt, clay, and gravel that were deposited by glacial loess. Alluvium is found along the river systems including West Branch Panther Creek. The Wedron Group consist of the Tiskilwa and Lemont formations but only the Lemont formation is found in the subsurface of the Roanoke quadrangle. The Lemont formation is a diamicton that ranges from blue to brown clay and is interpreted as a of silt loam. The Henry formation consists of an interbedded sand, gravel, and silt.This is interpreted as a glaciofluvial, and was formed when the melting of glaciers carried the deposits downstream. Finally the Peoria formation has been described as a light tan or brown silt to sandy silt eolian deposits.. References: http://isgs.illinois.edu/sites/isgs/files/maps/statewide/quaternary-deposits-8x11.pdf Acknowledgements: LiDAR and Soil survey was provided by the Illinois State Geologic Survey (ISGS). The Assistance of Janet Holden for deriving the LiDAR data, Crystal Williams for Geographic Information Systems (GIS) assistance . Method: First I took the soil survey from GIS and converted into formations based on parent material in the area. The use of topographic maps and moraine maps were used to add more detail to the shape of the where each formation lies within the given area. Along with LiDAR data these resources came together to create the final map. Introduction: The 7.5 minute Roanoke Quadrangle is located in Woodford county Illinois. The Wisconsin Glaciation was the main factor in creating the landscape and the caused mass transport as it moved down towards middle and lower Illinois. While the glaciers were stagnant, meltwater drained creating long, narrow deposits of sand and gravel, called eskers. As the glaciers retreated left behind moraines that make up this area. Discussion: This area was formed by the Wisconsin glaciation event. The advancements and the re-advancements of the glaciation event created the separate moraines and formations that run through this area. Each separate Lemont formation is representing different advances in the glaciation period. In this area the Lemont formation is broken up into the Lemont and the Heager member is separate in the top right hand corner. The henry formation in this area is classified by the Wasco facies that created a kame in the top right hand corner . The lower left hand corner includes mackinaw facies (henry formation) that are made of ice outwash deposits. https://www.isgs.illinois.edu/sites/isgs/files/maps/statewide/quaternary- deposits-8x11.pdf Results: Roanoke’s surficial geology primarily contains the Wasco and Mackinaw Members of the Henry Formation, the Heager member of the Lemont formation, the Peoria silt of the Henry formations and finally the Cahokia formation. All of these units were formed by the Wisconsin glacier event and are Quaternary in their age. The main formations in Roanoke is the Lemont and Heager formations. The Heager member is a red too gray clay loam diamicton, which typically contains gravel , sand, and silt. This formation is directly connected to the glacial ice and is contained in the subsurface. The Lemont formation is a silty clay loam diamicton that is lightly covered by loess. The Lemont formation consist of In the subsurface, Quaternary Tiskilwa Formation, Illinoisan units, and Pennsylvanian bedrock are present. The Cahokia is an alluvium stream deposit, that consists of bedded silts, clays, and gravel. The Peoria Silt is a loess deposit consisting of yellowish brown and gray silt with some sand. The Wasco Member of the Henry Formation is characterized by glacial landforms such as kames and eskers in the area and is found in the upper left hand corner of the mapping area.. The Mackinaw Member of the Henry Formation is found surrounding the river system and is an outwash deposit consisting of coarse sand and gravel. Both Lemont and Tiskilwa make up the Wedron Group but only the Lemont formation is found in the mapping area. Qwl Qwt Henry Formation (Wasco Facies) (Mackinaw facies) QUATERNARY DEPOSITS Description Unit Interpretation Henry Formation Sand and gravel with cobbles and boulders;stratified; yellowish brown to grayish brown; calcerous; usually clean and moderately well sorted;unconformably overlies older sand and gravel deposits, glacial diamictions, or bedrock;10 to 20 feet thick in tributary valleys and 10 to 80 feet thick in Illinois River valley Fluvial (riverine) and ice- marginal outwash deposits in Illinois River valley in terraces, former bars and channels and locally in terraces along tributaries to Illinois River; deposited proglacially by meltwater from distant glaciers; not consistently, differentiable from sand and gravel of the underlying Pearl Formation or Sankoty Sand Member where intervening tills are absent Lemont Formation Pebbly silty clay loam diamicton;unstratified; olive (oxidized) to grayish brown (unoxidized);firm to hard; compact; calcerous; massive to jointed; some cobbles few boulders; discontinuous beds of sand, gravel, silt, or clay; overlain in places by wind-blown silt (loess) of the Peoria Silt; unconformably overlies Dry Creek tongue, Tiskilwa Formation, or older units, 5 to 35 feet thick Till and associated sediment derived directly from glacial ice; overlain by thin covering of loess; occurs east of the western edge of the Eureka Moraine; absent in the Illinois River valley and tributary valleys, where removed by post-glacial erosion Haeger Member The Heager Formation consists of calcareous, red gray to gray, medium textured (clay loam to loam) diamicton that contains lenses of gravel, sand, silt, and clay. Typically, it oxidizes to red brown, brown, or yellow brown. Till and associated sediment derived directly from glacial ice;encountered in the subsurface only, underlying till of the Batestown Member Sand and gravel (stratified) This is an ice contact materials in Kames, kame terraces, and eskers. Qp Qc Peoria Silt Henry Formation Generally light yellow tan to gray silty to sandy silt; eolian deposits; contain beds of well- sorted sand, fossil snail shells, organic debris wood, and rarely clay layers Cahokia Formation The Peoria Silt is predominantly pro-glacial loess: derived from glacial meltwater channels; some f eolian sand; locally it contains colluviated and sheetwash silt Contact Silt and silty clay, interbedded with fine sand, and locally gravel and redeposited bedrock clasts; brownish soft to moderately stiff gray; calcareous or non- calcareous; typically overlies Cahokia or Henry Formations; interfingers with Cahokia floodplain facies; 5 to 30 feet thick Alluvial fan deposits; post-glacial redeposited loess and till in fans where streams and ravines emerge from uplands onto low-slope valley floors; subject to flooding Figure 1: Location map downloaded from the Illinois State Geological Survey. Figure 2: Location of 7 ½ minute quadrangle. Image captured from USGS webpage. Figure 3: Soils map interpretation. Data acquired from USDA webpage. Figure 4: LiDAR map. Data acquired from ISGS webpage. Quaternary Geologic Map Location Map Soils Interpretation Map LiDAR Map Qhw Qhm
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Surficial Geologic Map of the 7.5 Minute Roanoke Quadrangle in Woodford County, IL2015
Elena M. Topping, David H. Malone, and William E. Shields, Department of Geography-Geology, Illinois State UniversityAbstract
This study involved the construction of a geologic map of the Roanoke 7.5 minute quadrangle in Woodford County at a scale of 1:24,000. This area contained sections of the Eureka Moraine which is included in the Wisconsin glacier event. Methods used to construct this mapping
area included using soil data from soil survey, well data, as well as LiDAR data. There were four major sediment formations that were found at the subsurface in the Roanoke quadrangle. The formations include the Cahokia Alluvium, the Wedron Group (Lemont Formation), The
Henry Formation, and finally the Peoria formation. The Cahokia Alluvium consisted of interbedded sand, silt, clay, and gravel that were deposited by glacial loess. Alluvium is found along the river systems including West Branch Panther Creek. The Wedron Group consist of the
Tiskilwa and Lemont formations but only the Lemont formation is found in the subsurface of the Roanoke quadrangle. The Lemont formation is a diamicton that ranges from blue to brown clay and is interpreted as a of silt loam. The Henry formation consists of an interbedded
sand, gravel, and silt.This is interpreted as a glaciofluvial, and was formed when the melting of glaciers carried the deposits downstream. Finally the Peoria formation has been described as a light tan or brown silt to sandy silt eolian deposits..
References: http://isgs.illinois.edu/sites/isgs/files/maps/statewide/quaternary-deposits-8x11.pdf
Acknowledgements: LiDAR and Soil survey was provided by the Illinois State Geologic Survey (ISGS). The Assistance of Janet
Holden for deriving the LiDAR data, Crystal Williams for Geographic Information Systems (GIS) assistance.
Method: First I took the soil survey from GIS and converted into formations based on parent material in the area. The use of topographic
maps and moraine maps were used to add more detail to the shape of the where each formation lies within the given area. Along with LiDAR
data these resources came together to create the final map.
Introduction: The 7.5 minute Roanoke Quadrangle is located in Woodford county Illinois. The Wisconsin Glaciation was the main factor
in creating the landscape and the caused mass transport as it moved down towards middle and lower Illinois. While the glaciers were stagnant,
meltwater drained creating long, narrow deposits of sand and gravel, called eskers. As the glaciers retreated left behind moraines that make up
this area.
Discussion: This area was formed by the Wisconsin glaciation event. The advancements and the re-advancements of the glaciation event
created the separate moraines and formations that run through this area. Each separate Lemont formation is representing different advances in
the glaciation period. In this area the Lemont formation is broken up into the Lemont and the Heager member is separate in the top right hand
corner. The henry formation in this area is classified by the Wasco facies that created a kame in the top right hand corner . The lower left hand
corner includes mackinaw facies (henry formation) that are made of ice outwash deposits.
https://www.isgs.i l l inois.edu/sites/isgs/fi les/maps/statewide/quaternary-
deposits-8x11.pdf
Results: Roanoke’s surficial geology primarily contains the Wasco and Mackinaw Members of the Henry Formation, the Heager member of
the Lemont formation, the Peoria silt of the Henry formations and finally the Cahokia formation. All of these units were formed by the
Wisconsin glacier event and are Quaternary in their age. The main formations in Roanoke is the Lemont and Heager formations. The Heager
member is a red too gray clay loam diamicton, which typically contains gravel , sand, and silt. This formation is directly connected to the glacial
ice and is contained in the subsurface. The Lemont formation is a silty clay loam diamicton that is lightly covered by loess. The Lemont
formation consist of In the subsurface, Quaternary Tiskilwa Formation, Illinoisan units, and Pennsylvanian bedrock are present. The Cahokia is
an alluvium stream deposit, that consists of bedded silts, clays, and gravel. The Peoria Silt is a loess deposit consisting of yellowish brown and
gray silt with some sand. The Wasco Member of the Henry Formation is characterized by glacial landforms such as kames and eskers in the area
and is found in the upper left hand corner of the mapping area.. The Mackinaw Member of the Henry Formation is found surrounding the
river system and is an outwash deposit consisting of coarse sand and gravel. Both Lemont and Tiskilwa make up the Wedron Group but only the
Lemont formation is found in the mapping area.
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Henry Formation(Wasco Facies)
(Mackinaw facies)
QUATERNARY DEPOSITS
Description Unit Interpretation
Henry FormationSand and gravel with cobblesand boulders;stratified;yellowish brown to grayishbrown; calcerous; usuallyclean and moderately wellsorted;unconformablyoverlies older sand andgravel deposits, glacialdiamictions, or bedrock;10to 20 feet thick in tributaryvalleys and 10 to 80 feetthick in Illinois River valley
Fluvial (riverine) and ice-marginal outwash depositsin Illinois River valley interraces, former bars andchannels and locally interraces along tributariesto Illinois River; depositedproglacially by meltwaterfrom distant glaciers; notconsistently, differentiablefrom sand and gravel ofthe underlying PearlFormation or SankotySand Member whereintervening tills areabsent
Lemont Formation
Pebbly silty clay loamdiamicton;unstratified;olive (oxidized) to grayishbrown (unoxidized);firm tohard; compact; calcerous;massive to jointed; somecobbles few boulders;discontinuous beds of sand,gravel, silt, or clay; overlainin places by wind-blown silt(loess) of the Peoria Silt;unconformably overlies DryCreek tongue, TiskilwaFormation, or older units, 5to 35 feet thick
Till and associated sedimentderived directly from glacialice; overlain by thin coveringof loess; occurs east of thewestern edge of the EurekaMoraine; absent in the IllinoisRiver valley and tributaryvalleys, where removed bypost-glacial erosion
Haeger MemberThe Heager Formationconsists of calcareous, redgray to gray, mediumtextured (clay loam to loam)diamicton that containslenses of gravel, sand, silt,and clay. Typically, itoxidizes to red brown,brown, or yellow brown.
Till and associated sedimentderived directly from glacialice;encountered in thesubsurface only, underlyingtill of the Batestown Member
Sand and gravel(stratified)
This is an ice contactmaterials in Kames,kame terraces, and
eskers.
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Peoria SiltHenry FormationGenerally light yellow tan to
gray silty to sandy silt; eoliandeposits; contain beds of well-sorted sand, fossil snail shells,organic debris wood, andrarely clay layers
Cahokia Formation
The Peoria Silt ispredominantlypro-glacial loess: derivedfrom glacial meltwaterchannels; some feolian sand; locally itcontains colluviated andsheetwash silt
Contact
Silt and silty clay,interbedded with finesand, and locally graveland redeposited bedrockclasts; brownish soft tomoderately stiff gray;calcareous or non-calcareous; typicallyoverlies Cahokia or HenryFormations; interfingerswith Cahokia floodplainfacies; 5 to 30 feet thick
Alluvial fan deposits;post-glacial redepositedloess and till in fans wherestreams and ravines emergefrom uplands onto low-slopevalley floors; subject toflooding
Figure 1: Location map downloaded from the Illinois State Geological Survey.
Figure 2: Location of 7 ½ minute quadrangle. Image captured from USGS webpage.
Figure 3: Soils map interpretation. Data acquired from USDA webpage.
Figure 4: LiDAR map. Data acquired from ISGS webpage.
Quaternary Geologic Map Location Map Soils Interpretation Map LiDAR Map
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