Wind Cave National Park

Just south of Mt. Rushmore is the world’s fourth longest known cave; the Wind Cave. Over 125 miles of passages have been mapped out in this cave. Actually, this could be the world’s longest cave, but it’s not known for sure. As opposed to having just one or two main passage ways with some smaller tributary routes like many other caves, this cave is a three-dimensional matrix of crisscrossing tunnels. There are so many of these passages that within a five minute spelunking trek off the well-beaten path, you could be exploring cave that has never been seen by man. To give you a perspective, all of the 125+ miles of passages are beneath a 1.1 by 1.3 mile rectangle of surface land above. Present expeditions involved in mapping out the larger undiscovered parts of the cave require about a two-day journey just to begin. And how do they measure cave length in this modern, digital age? Tape measures. Flat Stanley was on the case to figure out why this cave was called Wind Cave. It turns out that the cave is so large and deep that it spans a significant amount of elevation, so significant that the barometric pressure difference between inside and outside the cave can often result in a strong wind at the cave entrance; up to 75 miles per hour! It was the sound of this howling wind that lead to the cave discovery. Wind Cave is home to over 95% of the word’s known boxwork. Boxwork is a curious cave formation that requires some fairly special circumstances to occur. The base rock of the cave is limestone. Through plate earthquakes and other natural phenomenon, small cracks developed in the limestone. Then as the rain fell on the ground above, the mineral gypsum was leached into the cracks. As the gypsum crystallized, it expanded, in the same way that water expands when it is frozen. This expansion acted to enlarge existing cracks in the sandstone, and to create new cracks as well. Gypsum again was leached into the cracks, and the process was repeated. Calcite also leaked into these cracks over the base gypsum, providing an enhanced strength. At some point, the cave became flooded for a very long time; long enough that the limestone actually dissolved in a mix of water, hydrogen sulfide, and sulfuric acid. The gypsum and calcite, resistant to the acid bath, were left behind in delicate and intricate patterns. Today we see them as fossilized cracks, which is pretty amazing!

Random Hole Leading to ???




Cave Boxwork




Me with a Well Abused Boxwork Sample

Mt. Rushmore

Tucked away in the Black Hills of South Dakota is Mt. Rushmore. Flat Stanley stopped by for a photo with four of our most famous presidents: George Washington, Thomas Jefferson, Theodore Roosevelt, and Abraham Lincoln Washington was chosen due to his involvement in the birth of the country; Jefferson due to his expansion of the country through the Louisiana Purchase of 1803; Lincoln due to his acts to preserve the country through the civil war; and Roosevelt due to his development of the United States as a world power and influence, as seen in the building of the Panama Canal. There is a very nice visitor center there, packed with information about the presidents and the carving of the monument. It’s amazing to think that dynamite and chisels could render such fine sculpture. Originally the monument had been planned to include about half of the upper bodies of the presidents as well. The project ran out of funding in 1941, and, due to World War II and the death of the project leader, was not further funded to complete the project. If you look closely, you can see where President Washington’s coat was going to be. Believe it or not, it takes some effort to maintain these rock stars. They are exposed to the elements of nature all year long. Most of the year is not a problem. However, winter can be harsh. If there are any open cracks in the faces, water could seep in. Then when the water freezes, the expansion could enlarge the cracks. Over time, such a process could lead to cracking their noses off! To combat the threat of freeze damage, the original sculptors packed a pasty mixture of lead carbonate and linseed oil into the cracks. Nowadays, the cracks are treated with silicone sealant, to which some granite sand is sprinkled on top so that it blends in with the rest of the rock face.