Soda Straw Landscape

A soda straw is a slender, hollow tube-like depositional feature that hangs on the roof of a karst cave and it gets its name because it looks like a straw. When calcium carbonate solution seeps from a crack in the cave roof, the solution droplets regularly (from seconds to hours) hang on the roof. Carbon dioxide in the droplets escape, causing the water droplets to become saturated. Calcium carbonate released from the droplets crystallises to form a very thin calcium membrane. When the water drops, the calcium membrane bursts, and a small amount of calcium carbonate is deposited on the cave roof, forming a ring. The ring’s diameter is similar to that of the water droplet. Dripping water droplets continue to supply calcium carbonate, and the ring will accumulate downwards to form a slender and hollow soda straw-like stalactite. The inner diameter of the straw is generally 3–4 mm, the wall thickness is 0.5–2 mm, and the lengths range from dozens of centimetres to several metres. Soda...