The Geology of Wind Cave National Park

The Geology of Wind Cave National Park
Wind Cave National Park in South Dakota is a unique park in terms of its geology, with the forces of erosion and other weathering creating a magnificent landscape. Below the ground is the third longest cave system in the nation, with its own geological quirks.


Wind Cave National Park has sandstone, limestone and pegmatite plateaus and ridges. It also has valleys carved into shale and schist.

Time Frame

The region's caves formed as far back as 320 million years ago, when sulfur dissolved the limestone in the area and created the passages.


The cave is famous for what geologists call "boxwork," a collection of thin calcite blades that jut out of the walls and ceilings. These combine to make what looks like a honeycomb of boxes.


Delicate growths of minerals such as aragonite and calcite branch off the ceilings to form "frostwork." This resembles the spreading ice crystals that characterize frost.

Cave Popcorn

Knob-like calcite formations appear on the cave walls. Because of their appearance, they are called "cave popcorn."


The minerals found in the caves include mirabilite, manganese, hematite, Huntite, endelilite, gypsum and Goethite.

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