SURFICIAL GEOLOGIC MAP OF THE SECOR 7.5 MINUTE QUADRANGLE, WOODFORD COUNTY, ILLINOIS

The surficial geologic map of Secor, Illinois was created on Canvas15 using various geologic data. The information gathered for the formation of the surficial geologic map came from the I.S.G.S, the U.S.G.S, and Woodford County Soil Survey. The quadrangle spans from 40° 37’ 30” to 40° 45’ north latitude and 89° 15’ to 80° 07’ 30” east longitude and is part of Woodford County, Illinois. The Makinaw River, Denman Creek, Panther Creek, and Walnut Creek all flow through the Southern part of the quadrangle, while the Red River flows through the northern and southern parts. The Eureka Moraine spans through NW corner to the SE corner of the map. South of the Eureka Moraine border is the Tiskilwa Formation, which is predominantly till. The Lemont and Peoria Formations make up the northern section of the quadrangle above the Eureka Moraine. The Lemont Formation is comprised of a till deposit and the Peoria Formation is mainly loess, which is only mapped if it is greater than 60” in thickness. In order to differentiate between the Lemont and Tiskilwa Formations, data from the Surficial Deposits of Illinois was used. The Cahokia Formation is observed along the creeks, and the lesser Henry Formation fills in the terraces. Outwash found in stream terraces is characteristic of the Henry Formation; while the Cahokia Formation is a loamy and silty alluvium found in floodplains.