Lead 210 and silicate profiles from sediments of the equatorial Pacific and South Atlantic ...

• Main Authors: DeMaster, David J, Cochran, James R
• Format: Article in Journal/Newspaper
• Language: English
• Published: PANGAEA 1982
• Subjects: Box corer; Gravity corer; Antarctic; Pacific; Antarc*
• Online Access: https://dx.doi.org/10.1594/pangaea.733921; https://doi.pangaea.de/10.1594/PANGAEA.733921

Particle mixing rates have been determined for 5 South Atlantic/Antarctic and 3 equatorial Pacific deep-sea cores using excess 210Pb and 32Si measurements. Radionuclide profiles from these siliceous, calcareous, and clay-rich sediments have been evaluated using a steady state vertical advection diffusion model. In Antarctic siliceous sediments210Pb mixing coefficients (0.04-0.16 cm**2/y) are in reasonable agreement with the 32Si mixing coefficient (0.2 or 0.4 cm**2/y, depending on 32Si half-life). In an equatorial Pacific sediment core, however, the 210Pb mixing coefficient (0.22 cm**2/y) is 3-7 times greater than the 32Si mixing coefficient (0.03 or 0.07 cm**2/y). The difference in 210Pb and 32Si mixing rates in the Pacific sediments results from: (1) non-steady state mixing and differences in characteristic time and depth scales of the two radionuclides, (2) preferential mixing of fine-grained clay particles containing most of the 210Pb activity relative to coarser particles (large radiolaria) containing ... : Supplement to: DeMaster, David J; Cochran, James R (1982): Particle mixing rates in deep-sea sediments determined from excess 210Pb and 32Si profiles. Earth and Planetary Science Letters, 61(2), 257-271 ...