Today we visited the Mammoth Site in Hot Springs, the world’s largest mammoth research facility. After viewing a 10 minute video we took a 30 minute guided tour of this active paleontological dig site. During the month of July, Earthwatch volunteers excavate, identify and study the Ice Age fossils. Which meant they weren't there today. We were a bit bummed as this is the first time we've visited that they weren't working & that's always interesting to watch. Nevertheless, we still enjoyed our visit.
The Mammoth Site really allows you to go back to the time when Ice Age mammoth, camel, and giant short-faced bear roamed the Great Plains of North America. Imagine a sudden collapse of a 60 foot deep sinkhole. The sinkhole formed approximately 26,000 years ago when a cavern in the Minnelusa limestone collapsed. The collapse caused a vertical shaft called a breccia (BREH-chee-uh) pipe to form. The ground surface of Spearfish Shale, a rock strata, also caved in. This opened a sixty-five foot deep, 120 X 150 foot sinkhole. This type of sinkhole is called "karst" (named after a region in Italy). The breccia pipe provided a chimney-like opening for a warm artesian spring to percolate up through the rocks to create a steeply-sided pond.
Enticed by the warm water and pond vegetation, the mammoths entered the pond to eat, drink or bathe and then could not escape. The mammoths were unable to find a foothold to scale the steep shale banks. Trapped in the pit, the mammoths ultimately died of starvation, exhaustion, or drowning.
The watering hole, active for about 350-700 years, slowly filled with layers of drying silt, sediments, and dying mammoths. The mud, which had aided in trapping the mammoths, now entombed and preserved the mammoth remains.
Eventually the sinkhole filled, and the artesian spring diverted to the lower elevation of Fall River, as the river cut deeper in the valley floor. Over thousands of years, the "hardened mud plug" inside the dried-up pond has remained stable. The surrounding dirt, the soft red Spearfish shale, ultimately eroded, leaving the sinkhole a hill.
For centuries the bones lay buried until discovered by chance in 1974 while excavating for a housing development. Now enclosed and protected by a climate controlled building, the sinkhole and the exhibit of mammoth bones attracts many visitors year round. The bones are displayed as they were discovered, in the now dry pond sediments, for an "in-situ" exhibit. Walkways allow visitors a close-up view of the fossils. To date, 55 mammoths have been identified, along with the remains of a giant short-faced bear, camel, llama, prairie dog, wolf, fish, and numerous invertebrates.
We took the time to enjoy the exhibits after our tour but all too soon it was time to get back on the road. We wanted to take the Wildlife Loop in today before it got to dark after visiting the Mammoth Site. I took many pics on today's trip so will split them into two posts. Mammoth Site today, Wildlife Loop tomorrow. So please stop back soon....