Mineral Resources On-Line Spatial Data
Mineral Resources > Online Spatial Data > Geology > by state > Tennessee Geology
Geologic units in Madison county, Tennessee
- Loess (Quaternary) at surface, covers 37 % of this area
Loess - Clayey and sandy silt, gray to brown, massive. Maximum thickness about 100 feet along bluffs of Mississippi River; thins eastward. (Minimum mapped thickness 4 feet.)
- Alluvial deposits (Quaternary) at surface, covers 11 % of this area
Alluvial Deposits - Sand, silt, clay, and gravel. In flood plain of Mississippi River more than 100 feet thick; in smaller streams generally less than 20 feet thick.
- Midway Group including Porters Creek Clay and Clayton Formation (Tertiary) at surface, covers 8 % of this area
Midway Group - includes Porters Creek Clay - Pale-brown to brownish-gray, massive, blocky clay; locally contains glauconitic sand. Thickness 130 to 170 feet. Also includes Clayton Formation- Glauconitic sand, argillaceous and locally fossiliferous; at base in Hardeman County is an impure fossiliferous limestone. Thickness 30 to 70 feet.
- Claiborne and Wilcox Formation (Tertiary) at surface, covers 44 % of this area
Claiborne and Wilcox Formations -- Irregularly bedded sand, locally interbedded with lenses and beds of gray to white clay, silty clay, lignitic clay, and lignite. Thickness more than 400 feet.