Cave Popcorn: Delicate Wall Decorations
Cave popcorn (also called cave grapes or corraloids) is a catchall term describing a small, bumpy speleothem that usually does not have a central conduit, unlike stalactites. Although these formations are given the same name, they can form in very different ways depending on the location in the cave. Popcorn can be deposited on the walls of a standing pool of water (like on the rimstone dams in the Cypress Swamp and the small hollow along the West Room path). Most of the popcorn in Lehman Caves was not formed under water, however. Other ways popcorn can form is by a thin film of water flowing over an irregular surface, splashing water, and by water seeping through the bedrock. The seepage method is probably predominant at Lehman Caves. The water "sweats" out of the wall and the crystals of the popcorn. The water then evaporates, or sometimes drips, and leaves calcite deposits.
Last updated: February 28, 2015