- The table organizes geological information by Era (e.g., Cenozoic, Mesozoic), System (e.g., Quaternary, Tertiary), and Group/Formation (e.g., White River Group, Pierre Shale).
- Each entry includes an abbreviation for the stratigraphic unit, the geologic unit name, its thickness in feet, and a descriptive summary of its composition and characteristics.
- The data is structured chronologically from youngest (Cenozoic) to oldest (Precambrian), with sub-divisions like Periods (e.g., Tertiary, Cretaceous) and specific Formations (e.g., Niobrara Formation, Greenhorn Formation).
- Thickness values range from 0–50 feet (e.g., Ogallala Formation) to over 1,000 feet (e.g., Pierre Shale at 1,000–2,700 feet).
- Descriptions detail lithology (e.g., sand, silt, shale, limestone), depositional environment (e.g., marine, fluvial), and notable features (e.g., concretions, fossils, color variations).
- The table also notes modifications based on drill-hole data and credits the source as South Dakota School of Mines & Technology (January 1994).
Parent Tip: Review the logic above to help your child master the concept of geologic column worksheet.
