Kaik,
The caption claims the environment is virtually identical to a nearby famous cave.
George Rogers Clark Memorial is built on the bank of the Wabash River at Vincennes, Indiana. The limestone came from Bedford Quarry, near Bedford, Indiana, just six miles from the entrance of Blue Springs Cave, one of the most beautifully decorated caves in the nation. Water percolates down through cracks in the memorial building into the basement as it does in the cave and the result is the same kind of formations as found in the cave.
It certainly looks identical to cave formations claimed to be millions of years old. A better explanation is not that the chemical make up might be different, but that the rate of mineral deposit varied from what ever testing was originally done to determine the rate of mineral flow.
This huge mineral mound was cause by a farmer's field pipe that was left flowing for 100 years and formed this mineral rich deposit. It is called the Teepee Formation in Thermopolis, Wyoming.
Here's some beautiful formations in a manmade tunnel. Notice the sign.