Sediment isotope tomography (SIT) model version 1

Geochronology using 210Pb is the principal method used to quantify sediment accumulation in rapidly depositing aquatic environments such as lakes, estuaries, continental shelves, and submarine canyons. This method is based on the radioactive decay of 210Pb with depth in a column of sediment. The decay through time of 210Pb P(t) is governed by the exponential law P(t) = P0 exp( -λt) where P0 is the surficial concentration at time t = 0, and λ is the decay constant (3.114 sm-bullet 10-2 year [yr]-1 for 210Pb). If the sedimentation rate is constant, then elapsed time t is connected to burial depth x, through x = Vt where V is the sedimentation velocity. Accordingly, P(x) = P0exp( -λx/V). The sedimentation velocity is obtained from an exponential fit to the measured 210Pb data P(x), with depth x