Friday, July 22, 2011

The Mammoths of Hot Springs

The year is 1974. You're operating a piece of earth-moving equipment at the site of a housing development near Hot Springs, SD. You've removed a few cubic yards of soil when you strike something that looks unusual--extremely unusual. You have discovered what today is the world's largest Columbian mammoth exhibit and a world-renown research center for Pleistocene studies.

Now enclosed and protected by a climate controlled building, the site has displays of bones as they were discovered.

About 26,000 years ago, a sinkhole formed when a cavern in the Minnelusa limestone collapsed and opened a sixty-five foot deep 120 X 150 foot sinkhole. A chimney-like opening enabled a warm artesian spring to percolate up through the rocks to create a steeply-sided pond.

Drawn to the warm water and pond vegetation, the mammoths entered the pond to eat and drink and then could not escape. They 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.

Eventually the sinkhole filled, and the artesian spring diverted to the lower elevation of Fall River.

The next five photos show the same area of the display. This photo (above) shows the size of the dig relative to the size of people.

Our tour guide described the process of determining which bones go to the same skeleton--a big challenge made a bit easier due to the fact of the "layering" of the skeletons as the water source dried up and the soil hardened over thousands of years.

Referring to the photo above, this photo (right) shows the skeleton portion in the foreground,

this portion appears midway in the overview photo, and

this photo shows the skeleton in the background (upper portion) of the overview photo.

The fact that the bones are displayed in the now dry pond sediments just as they were discovered makes for a fascinating "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.

This photo shows two teeth of a mammoth.

Our stop at the Mammoth Site was all too brief, so I did not get the information identifying the three skeletons in the lobby of the main hall. Needless to say, they were quite impressive.

“The Mammoth Site is not just a window into the past—it’s as close to being a true time machine as you’ll find, with some of the best ice-age fossils on the planet on permanent display.” --Ross MacPhee, American Museum of Natural History, New York City.