Large deposits of barite were discovered in association with biological communities, indicative of active fluid seepage on the middle slope of Paita and in the Chiclayo Canyon, in the Peru margin. It is postulated that the barium source for the deposits is associated with the high concentration of non-detrital barite buried in sediments from this high productivity region. Barite is remobilized within the sediment column due to sulfate depletion. Subsequent flushing of the barium-rich fluids from the sediment to the bottom water, leads to the formation of barite deposits at the cold vent sites. Observations indicate that the barite deposits associated with fluid seepage in the Peru margin are restricted to areas where slope failure has exposed sequences deep enough such that the barium-rich fluids do not encounter sulfate-bearing pore fluids before emanating at the seafloor.