Some considerations of the ²¹⁰Pb constant rate of supply (CRS) dating model

Abstract

One of the most widely used radionuclides in the study of recent sedimentation processes is 210Pb. Its depth profile in sediments is used as input for various dating models, which provide chronologies, mass fluxes, and sedimentation rates. In this work we revisited the CRS (constant rate of supply) model, widely used for dating sediments through 210Pb. A more general hypothesis (periodic flux [PF]) was proposed and, although it confirmed the validity of CRS chronology, a detailed analysis of the mass sedimentation formula pointed out an inconsistency of the cited model. A new mass sedimentation formula was proposed and validated with a lake sediment core and four marine sediment cores.

Historical changes of sediments and mollusk assemblages in the Gulf of Batabanó (Caribbean Sea) in the twentieth century

“…The radionuclide 210 Pb has been widely used as a geochronometer of recent sediments in order to establish historical changes in decennial to secular time scales (e.g., Appleby 2008;Sanchez-Cabeza et al 2000). The combination of dating with the analysis of the ecological structure of fossil assemblages is a powerful tool for disentangling historical processes.…”

Geochronology of anthropogenic radionuclides in Ribeira Bay sediments, Rio de Janeiro, Brazil

“…The sediment core chronologies were determined using the Constant Flux e Constant Sediment Accumulation Rate (CF:CS) method (see, for example: Joshi and Shukla, 1991;Appleby and Oldfield, 1992;Sanchez-Cabeza et al, 2000). First, logarithmic plots of 210 Pb concentration versus sediment depth were made.…”

Guanabara bay sedimentation rates based on 210Pb dating: reviewing the existing data and adding new data

“…The sediment core chronologies were determined using the constant rate of supply (CRS) model [17][18][19] for the sediment cores, BG-08 and BG-28. Logarithmic plots of the 210 Pb concentration versus sediment depth were first built, and excess 210 Pb was calculated by subtracting the constant value observed in the core bottom, as shown in Figures 2a, b and c. According to Masqué et al,20 these velocities should be considered as an upper limit.…”