TY - JOUR
T1 - The validity of steady-state flux calculations in early diagenesis
T2 - a computer simulation of deep-sea silica diagenesis
AU - Rabouille, Christophe
AU - Gaillard, Jean François
PY - 1990/4
Y1 - 1990/4
N2 - A time-dependent mathematical model for the early diagenesis of silica is used to examine closely the dynamic behaviour of the sediment under two types of perturbation: the mixing of the sediment by benthic megafauna and turbidite deposition. Numerical simulations provide times for which steady state is re-established, and times for which the perturbation signature remains detectable for both dissolved and biogenic solid silica systems. Simulation are executed for different trophic supplies and benthic populations densities. According to the density of megafauna population, we provide estimates of flux variability. The calculated dissolved silica flux at the sediment-water interface can increase up to 35% with respect to the steady-state calculation. This contribution is not negligible when quantifying the recycling of silica within the sediment. Times needed to go back to steady state are rather short on the sedimentary time scale for both systems (≅100 h for the dissolved part of the system and less than one year for the solid part). Hence, we believe that surface perturbations are hardly recorded at depth in the sediments. We conclude that changes in sediment composition at depth may be more reliably linked to variations in deposition conditions.
AB - A time-dependent mathematical model for the early diagenesis of silica is used to examine closely the dynamic behaviour of the sediment under two types of perturbation: the mixing of the sediment by benthic megafauna and turbidite deposition. Numerical simulations provide times for which steady state is re-established, and times for which the perturbation signature remains detectable for both dissolved and biogenic solid silica systems. Simulation are executed for different trophic supplies and benthic populations densities. According to the density of megafauna population, we provide estimates of flux variability. The calculated dissolved silica flux at the sediment-water interface can increase up to 35% with respect to the steady-state calculation. This contribution is not negligible when quantifying the recycling of silica within the sediment. Times needed to go back to steady state are rather short on the sedimentary time scale for both systems (≅100 h for the dissolved part of the system and less than one year for the solid part). Hence, we believe that surface perturbations are hardly recorded at depth in the sediments. We conclude that changes in sediment composition at depth may be more reliably linked to variations in deposition conditions.
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U2 - 10.1016/0198-0149(90)90094-C
DO - 10.1016/0198-0149(90)90094-C
M3 - Article
AN - SCOPUS:0025262638
SN - 0198-0149
VL - 37
SP - 625
EP - 646
JO - Deep Sea Research Part A, Oceanographic Research Papers
JF - Deep Sea Research Part A, Oceanographic Research Papers
IS - 4
ER -