Drops that fall from a cave ceiling splash onto the floor and deposit mineral there. A stalagmite is the upward-growing mound that results. Like stalactites, most are calcite, though other minerals occur in some caves.

Stalagmites tend to be broader and more rounded than the slender stalactites above them. When a stalactite and stalagmite meet they form a column. Growth is intermittent and depends on the supply of drip water and its degree of supersaturation.

Because stalagmites grow from the floor and are less easily disturbed, they are favored for paleoclimate studies. Layers within them can be dated by uranium-series methods and analyzed for isotopic and chemical proxies of temperature and rainfall. A single well-dated stalagmite can provide a continuous climate record spanning tens of thousands of years.

• Mineral formation rising from a cave floor
• Grows upward from dripping water
• Often paired with overlying stalactites
• Valuable archive of past climate