Bedrock Topography, Thickness Maps and a Three-dimensional Model of Silurian Rocks in Lake County, Illinois

               

Silurian

Silurian rocks, consisting mainly of pure to silty dolomite, form the most important bedrock aquifer supplying residences in Lake County. Local porosity and permeability are mainly the result of fractures and dissolution cavities in the dolomite. There is little to no matrix porosity; therefore the dolomite does not have adequate capacity for municipal water wells. The water is recharged locally from precipitation and is susceptible to groundwater contamination.

Left is a three-dimensional representation of the thickness of the Silurian age strata.

Updated 10/27/2009 SLD