Geologic units in Hodgeman county, Kansas

Additional scientific data in this geographic area

Loess (Holocene to Pleistocene) at surface, covers 40 % of this area

eolian silts

Carlile Shale (Late Cretaceous) at surface, covers 18 % of this area

Chalky shale with bentonite and thick chalk beds, dark gray fissile shale containing septarian concretions, and fine-grained sandstone.

Greenhorn Limestone and Graneros Shale (Late Cretaceous) at surface, covers 15 % of this area

Greenhorn FM- thin bedded gray, chalky limestone and calcareous shale. Graneros Shale- fissile, noncalcareous, gray shale locally contains sandstone and siltstone beds.

Alluvium (Holocene to Pleistocene) at surface, covers 10 % of this area

unconsolidated sand, silt, clay, and gravel

Ogallala Formation (Miocene) at surface, covers 8 % of this area

massive to cross-bedded, generally arkosic sand, silt and gravel, locally cemented with calcium carbonate; also contains limestone, volcanic ash, diatomaceous marl, opaline sandstone and bentonitic clay

Dakota Formation (Early Cretaceous) at surface, covers 5 % of this area

White, gray, red, brown and tan kaolinitic claystone, mudstone, shale and siltstone interbedded with grayish to yellowish brown thick lenticular sandstone beds. It also contains lignite and sandstone is commonly well cemented with iron oxide and calcite.

Alluvium (Pleistocene) at surface, covers 3 % of this area

unconsolidated sand, silt, clay, and gravel

Niobrara Chalk (Late Cretaceous) at surface, covers 0.1 % of this area

Interbedded, soft, light-gray calcareous shale and chalk