How does a stalagmite grow from a cave floor?

A stalagmite grows upward from a cave floor as a result of mineral-rich water dripping from above. The process begins when rainwater infiltrates the soil, absorbs carbon dioxide to form a dilute carbonic acid, and dissolves calcite from the overlying limestone bedrock.123

As this water emerges from the cave ceiling and drips onto the floor, it enters the cave atmosphere, where it loses carbon dioxide. This loss reduces the water's ability to hold the dissolved minerals in solution, causing the calcium carbonate to precipitate. Unlike stalactites, which form around a central canal, stalagmites are built up from these falling droplets as superimposed caps or layers of mineral deposits. Over time, these deposits accumulate into various shapes, such as mounds, pagodas, or slender columns. If a stalagmite continues to grow until it meets a downward-growing stalactite, they may eventually join to form a column.123