Evaluation of sediment trace metal records as paleoproductivity and paleoxygenation proxies in the upwelling center off Concepción, Chile (36°S)

► Two sediment cores were collected at the upper boundary and within the OMZ. ► Metals, biogenic opal, stable isotopes and TOC were measured at 1 cm resolution. ► U, Cd and Mo authigenic enrichment along with heavier δ15N suggest suboxic periods. ► Suboxic conditions were associated with high fluxes of organic material to the bottom. ► High inputs of refractive detrital material should occur during oxic periods.