The world that exists deep below the surface in Carlsbad Caverns National Park is a subterranean marvel. Created slowly over the millennia, its beautiful formations awe visitors year-round. Considered by many as the Eighth Wonder of the World, it is one of twenty World Heritage Sites in the United States.
Visitors walking through the cave today are seeing but a snapshot of the area’s geologic history. Cavern development began about 250 million years ago when a reef formed along the edge of an inland sea. The sea eventually evaporated and left the reef buried under deposits of gypsum and salts.
Then, 20 to 30 million years later, the Guadalupe Mountains were uplifted thousands of feet above sea level, fracturing the ancient reef. Rainwater percolated down from the surface and mixed with hydrogen sulfide-rich brine from local oil and gas deposits to form sulfuric acid. This very strong acid carved out the large rooms and passageways that exist today. Finally, about 500,000 years ago, after groundwater levels had dropped, the slow process of speleothem – stalactites, stalagmites, and flowstone – formation began with a single drop of water. Drop by drop…billions and billions of drops later, park visitors marvel at these monuments of time.