Source mixing and kinetic effects on REE patterns in a stalagmite

Abstract

We investigate the REE pattern in a stalagmite developed 18-4.5 ka in Maboroshi cave in Hiroshima Prefecture for understanding its potential use as a paleoenvironmental archive. The geology consists mainly of limestone, which is intruded by andesite dyke. The limestone-normalized REE patterns of the stalagmite show clear HREE enriched pattern. This is likely due to the higher solubility of HREE than LREE during dissolution of bedrock. The degree of HREE enrichment is influenced by growth kinetics of calcite. The other feature of REE pattern in the stalagmite is positive Eu anomaly, which is inherited from that in plagioclase in weathered andesite.