Climatic Data, Cave Records

CAVES HAVE PROVIDED climate researchers with several useful ways to learn about past climates. In caves that are connected to the surface, plant (particularly pollen) and animal remains allow scientists to study floral and faunal successions over time, which often reflect concurrent climate shifts. Cave deposits, collectively called speleothems (for example, stalagmites and stalagtites) provide interesting information that, though geochemical techniques are still being refined, promises a detailed and well-constrained record of past climate variability.

Caves are commonly found in limestone (calcium carbonate, CaCO3) bedrock settings. When precipitation moves through a soil horizon, it picks up dissolved carbon dioxide (CO2) produced in organic decomposition, thereby becoming mildly acidic. The acidic groundwater then slowly dissolves CaCO3 bed-rock, forming caves over time. Speleothems form when dissolved CaCO3 precipitates ...