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Mineral Resources On-Line Spatial Data

Lower Devonian

Lower Devonian
StateIllinois
NameLower Devonian
Geologic ageDevonian
Original map label6170
CommentsThe lower Devonian includes the following formations: Clear Creek Chert, Backbone Limestone, Grassy Knob Chert, Bailey Limestone. Based on the statigraphic column on the 1967 paper map, these units collectively consist of about 60% limestone, 30% chert, and 10% dolomite.
Primary rock typelimestone
Secondary rock typechert
Other rock typesdolostone (dolomite)
Lithologic constituents
Major
Sedimentary > Carbonate > LimestoneThe lower Devonian includes the following formations: Clear Creek Chert, Backbone Limestone, Grassy Knob Chert, Bailey Limestone. Based on the statigraphic column on the 1967 paper map, these units collectively consist of about 60% limestone, 30% chert, and 10% dolomite.
Minor
Sedimentary > Chemical > ChertThe lower Devonian includes the following formations: Clear Creek Chert, Backbone Limestone, Grassy Knob Chert, Bailey Limestone. Based on the statigraphic column on the 1967 paper map, these units collectively consist of about 60% limestone, 30% chert, and 10% dolomite.
Sedimentary > Carbonate > DolostoneThe lower Devonian includes the following formations: Clear Creek Chert, Backbone Limestone, Grassy Knob Chert, Bailey Limestone. Based on the statigraphic column on the 1967 paper map, these units collectively consist of about 60% limestone, 30% chert, and 10% dolomite.
Map references
Willman, H.B., and others, (compilers), 1967, Geologic Map of Illinois: Illinois State Geological Survey, scale= 1:500,000, paper.
Unit references
Willman, H.B., and others, (compilers), 1967, Geologic Map of Illinois: Illinois State Geological Survey, scale= 1:500,000, paper.
Geographic coverageAlexander - Jackson - Pulaski - Union

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