Speleothem

A mineral deposit formed in a cave, usually when dissolved minerals precipitate from water. Stalactites and stalagmites are familiar examples.

Calcite: A crystalline form of calcium carbonate and a common mineral in limestone and cave deposits. Calcite precipitating from water forms many familiar cave speleothems.
Stalactite: A cave deposit that hangs from a ceiling or overhang. It grows downward as mineral-bearing water loses carbon dioxide and deposits minerals.
Paleoclimatology: The study of climates and climate change in Earth's past. Speleothem layers provide dated records of past climate conditions.
Cave of the Crystals: A cave in Naica, Mexico, famous for exceptionally large gypsum crystals. Its crystals are spectacular cave mineral deposits, though they formed differently from ordinary dripstone.
Carbon dioxide: A colorless gas that dissolves in water and participates in carbonate chemistry. Carbon dioxide loss from cave water can trigger calcium carbonate precipitation.
Stalagmite: A cave deposit that rises from the floor beneath dripping water. It forms where drops splash and leave minerals on the cave floor.
Oxygen isotope ratio: The relative abundance of oxygen isotopes in a sample, commonly expressed as δ18O. Measurements in speleothem calcite can reflect changes in rainfall and temperature.
Carlsbad Caverns: A cave system in New Mexico known for extensive limestone chambers and formations. Its chambers contain varied examples of cave mineral deposits.
Karst: A landscape shaped by the dissolution of soluble rocks, especially limestone. Karst drainage supplies the mineral-rich water from which many speleothems form.
Flowstone: A sheet-like cave deposit formed by flowing water over a surface. It shows how mineral precipitation can build broad coatings rather than hanging or rising forms.

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