SURFICIAL GEOLOGIC MAP OF THE METAMORA 7.5 MINUTE QUADRANGLE IN WOODFORD COUNTY, IL

This study involved constructing a surficial geologic map of the Metamora 7.5 Minute Quadrangle in Woodford County, Illinois (Scale 1:24,000). This quadrangle includes the Metamora moraine and part of the Bloomington Moraine, both moraines are of Wisconsin age. Methods used in the development of this geologic map included conversion of soil survey data, as well as LiDAR data and well water data. Four major Quaternary age sediment units are exposed in the Metamora Quadrangle. These formations include the Henry Formation, Wedron Group, the Peoria Silt, and the Cahokia Alluvium. The Henry Formation is gravel and sand interpreted to be valley train outwash. The surface and subsurface is the primary location for outwash gravel. The Wedron Group consists of both the Tiskilwa and Lemont Formations. Tiskilwa is a red-grey to grey calcerous clay loam or loam. This formation lies South and West of the Metamora Moraine. Lemont is a diamicton consisting of grey, blue, brown, black, and green clay interpreted to be a combination of loamy till and silty loess. The Lemont is present in the Metamora Moraine as well as areas to the North and East of it. The Peoria Silt is light yellow tan to grey sandy silt interpreted to be predominantly a pro-glacial loess. This loess is derived from glacial meltwater channels. Lastly, the Cahokia Alluvium is a silty and silty clay interbedded with a fine sand. This Formation is interpreted to be post-glacial loess and till that had been redeposited in fans where streams and ravines emerge from uplands and onto low-slope valley floors.