Variations spatiales et temporelles du césium-137 et du carbone dans des sédiments du fjord du Saguenay

Abstract

The accumulation rate of sediments in the Saguenay Fjord, Quebec, Canada, established from 137 Cs activity measured in 19 cores, varies between > 1.0 cm/year upstream and 0.2 cm/year downstream. Cesium-137 profiles in cores from the northern basin follow that of fallouts on the ground and reflect the impact of a sudden inflow of clay from a major mudslide. However, 137 Cs accumulation in the larger basin seems less sensitive to external influences.Carbon content and the C/N ratio are higher upstream than downstream. Based on 137 Cs dating, core sections show carbon contents that reflect changes caused by the forest industry over the years. [Journal Translation]