Wind Cave National Park — August 20, 2014

Wind Cave National Park is the site of one of the worlds longest and most complex caves and 33,851 acres of mixed-grass prairie, ponderosa pine forest, and associated wildlife. The cave is well known for its unusual geology, outstanding displays of boxwork, a rare cave formation composed of thin calcite fins resembling honeycombs, and the winds at the caves entrance. The cave also contains a variety of other cave formations such as popcorn, frostwork, and flowstone. Continued exploration is still occuring as cavers actively search for new passages in this complex maze.

The mixed-grass prairie in the park above the cave is one of the few remaining and is home to native wildlife such as bison, elk, pronghorn mule deer, coyotes and prairie dogs.

While many speleothems have formed as water has dripped into the passages, the most conspicuous feature of Wind Cave, boxwork, has probably formed differently. Boxwork is found in small amounts in other caves, but perhaps in no other cave in the world is boxwork so well-formed and abundant as in Wind Cave. Boxwork is made of thin blades of calcite that project from cave walls and ceilings, forming a honeycomb pattern. The fins intersect one another at various angles, forming boxes on all cave surfaces. Boxwork is largely confined to dolomite layers in the middle and lower levels of Wind Cave.

The origin of boxwork remains a mystery. According to one theory, many of the bedrock walls in Wind Cave have resistant fins of calcite from which the intervening limestone and dolomite bedrock has been removed by weathering. The veins in which the boxwork formed are along narrow fractures resulting from stresses produced when the mineral gypsum dried and rehydrated. The calcite formed in these fractures taking on the shape of the original gypsum crystals.

The original entrance to the cave is a small hole, barely large enough for a small person to squeeze into.  Barometric disparities between the inside and outside cause “winds” to flow through that small hole, and that is how the cave was discovered by white settlers in 1881.  Before that, and continuing into the present, the cave has been regarded as sacred by Amerindians.  Indeed, when we were there, small packets of tobacco wrapped in bright cloth were tied onto bushes just opposite the small cave opening.

A number of different “tours” of the cave are available.  We began ours by entering through a steel door and into an excavated passage that ran some 20 feet before encountering the original cave.  We descended down steps and inclines to a depth of 200 feet, sometimes squeezing along narrow passageways and other times entering fairly large rooms.  We saw virtually no stalactites or stalagmites, since the cave is so dry. We exited the cave via a slow limited-weight elevator that permitted only 10 persons at a time.

When we left the cave we paused to photograph some pronghorns and some bison, and then proceeded to the campgrounds at Bismarck Lake in Custer State Park — the very same that we had used on our trip with the Dockters in late July.