Experimental determination of the 14C initial activity of calcareous deposits

Abstract

We have reconstructed the initial activity of calcareous sediments by 1) measuring the 14C activity of recent pre-bomb-test calcareous deposits, 2) calculating the ratio of the 14C activity of the calcareous sediment to that of the adjacent coeval wood, and 3) extrapolating 14C of the deep lacustrine sediment layers to the surface, assuming a constant sedimentation rate. We show here that the uppermost sediment is affected by the global increase of atmospheric 14C activity due to thermonuclear bomb tests in the early 1960s. -from Authors