The huge rooms were formed when the water table paused and fresh water mixed with sulfuric acid for a long period of time in one specific place. The Big Room (4,000 feet long, 625 feet wide and 255 feet high) is the largest natural limestone chamber in the United States. When the water drained from the cave areas, loose sections fell and surface water entered through every fissure, picking up dissolved limestone along the way. When the limestone precipitated out as calcite, about 800,000 years ago, it acted as an artist’s tool, decorating a multitude of formations. It dripped, forming stalactites (which hang “tight” to the ceiling) and stalagmites (which seem to grow from the floor).
The Big Room is the largest natural limestone chamber in the United States.
Stalactites start as “soda straws”, rings of calcite deposited on the outside of drops of water entering through a fissure. The rate of drip determines their shape: fast growing ones are long and thin; slow-growing ones are stubby. Stalagmites, like those in the Hall of Giants, form when water falls over a long distance and splashes over a wide area. Giant Dome (at 60 feet, it is the tallest formation in the Big Room) is actually a column, formed when a stalactite and a stalagmite meet. Fairyland is an area of popcorn-covered stalagmites. The popcorn effect is caused by condensation.
Mirror Lake, like all the “lakes” and “springs” in the Caverns, is actually a drip pool, formed and fed by surface water. When the climate at Carlsbad began to dry, most formations stopped growing, and today 95% of them are dormant. Crystal Springs Dome is the largest active formation in the Cavern. Water, entering through fractures and pores, travels through many pathways throughout the cave. Because, the pathways vary, so does the amount of time it takes the rainwater to reach Crystal Springs Dome, from two weeks to more than a year….this fantasy land is full of complexity.
Stalagmites form when water falls over a long distance and splashes over a wide area.
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