DIAGENETIC TRACE-METAL PROFILES IN ARCTIC LAKE-SEDIMENTS

Heterogeneous trace-metal profiles have been found in the slowly accumulating sediments of Toolik Lake, AK [USA]. Elevated Ba,Co,Cu,Mo, and Ni concentrations near the sediment-water interface are inconsistent with inputs from recent watershed disturbances. The apparent cause of trace-metal enrichment is comigration with Mn and Fe in pore water resulting in narrow bands of trace-metal enrichment associated with high (> 15%) concentrations of Mn and Fe. The misinterpretation of diagenetic enrichments as anthropogenic features is a potential problem in midly reducing, Mn- and Fe-rich lake sediments.