May 6, 2025
Big Basin | Photo Scott Bean, Text Keith Miller, authors of Kansas Landscapes: A Photographic Tour of the Region's Geological History, licensed to Sierra Club Kansas Chapter
The Big Basin Prairie Preserve Wildlife Area in Clark County is named for the Big Basin, a large circular depression about a mile in diameter. Its steep sides can be seen in this photograph. The depression is the result of subsidence of the surface following the solution of thick sub-surface gypsum salt layers by groundwater. Solution of these buried gypsum layers has also produced caves and sinkholes. Gypsum layers are common in parts of the Red Hills, and were formed by the evaporation of water in coastal areas in the hot dry climate of the late Permian.