"The Labyrinth"

Deep within the limestone cavities that would become Carlsbad Caverns, sulfuric acid was formed when groundwater combined with hydrogen sulfide gas from underlying oil deposits. This acid slowly carved out sinuous passages like those seen here in "The Labyrinth." Later, dripping water formed stalactites in some of these passages. Air movement evaporated the water, leaving lumpy deposits of calcite called "cave popcorn." Oxidized minerals such as iron and manganese, produce spectacular colors in the formations.