A Look Back...5 Years

Deposits of calcite in caves (speleothems) have served as important paleoclimate proxies, providing detailed information of late Pleistocene and Holocene change.  To explore the use of these important proxies, Banner et al. described a series of studies of speleothem growth rates from several sites in three present-day caves and compared these data with measurements of controlling factors (temperature, rainfall, drip rates, drip-water composition, and cave-air composition).  The results suggested that growth rate was most closely influenced “by regional temperature effects on ventilation of cave-air CO₂ concentrations and/or drip-water CO₂ contents,” although local changes in drip rate changed the absolute rates within each cage.  The results suggested that “growth-rate variations in ancient speleothems may serve as a paleoenvironmental proxy with seasonal resolution.”

Seasonal variations in modern speleothem calcite growth in Central Texas, USA by Jay L. Banner, Amber Guilfoyle, Eric W. James, Libby A. Stern and MaryLynn Musgrove