The 2002-2003 El Niño recorded in Australian cave drip waters: Implications for reconstructing rainfall histories using stalagmites

A 30‐month study of drip hydrochemistry from Kooringa Cave, eastern Australia, revealed a clear geochemical response to the 2002–2003 El Niño. Through the drought, drip discharge fell to base flow, drip Ca2+ concentrations fell by half and drip Mg/Ca and Sr/Ca increased in a co‐varying pattern. Calcite Mg/Ca and Sr/Ca predicted from drip waters displayed a marked increase through, and just beyond, the period of greatest moisture deficit. The results suggest that stalagmites from shallow caves in drought‐sensitive eastern Australia potentially preserve a valuable record of El Niño‐La Niña history.