Do caves form slowly from descending weak acidic water or quickly from ascending strong acidic water?
For many decades, caves have been argued to have formed due to weak acidic (carbonic acid) water descending from above caves to slowly dissolve them over thousands of years. However, many of the caves in the western United States (and elsewhere) are now acknowledged to be caves that formed more quickly from stronger acidic water (e.g., sulfuric acid) ascending from below caves (hypogene speleogenesis). These images provide evidence that the caves of the eastern U.S. are also hypogene caves. The presence of three morphological features are strong diagnostic features of hypogene caves: inlets at the base of caves (feeders), transitional features (channels), and outlet features at the top of caves (cupolas).
Cupolas are dome structures on cave ceilings were pooled acidic water lost its dissolution potential before breaking into the next level of the cave or surface above the cave.
