Evaluating the historical sedimentation patterns in two different Mediterranean deep environments (Sardinia and Sicily Channels)

Abstract

The sediment accumulation rate in the Sardinia and Sicily channels in the central part of the Mediterranean Sea was studied by using short-lived radionuclides (210Pb and 137Cs) in two deep sediment cores. Different sedimentation regimes were identified indicating substantial differences in accumulation rates and historical patterns. The 210Pb-derived mean accumulation rate found in the Strait of Sardinia was 0.05 g.cm-2.y-1, lower than that in Sicily Channel (0.1 g.cm-2.y-1) suggesting an inverse correlation with water depth. Excess 210Pb inventories were 24 ± 1 and 6.0 ± 0.4 kBq.m-2, while the fluxes to the sediment were 745 ± 31 and 188 ± 11 Bq.m-2.y-1 in Sicily and Sardinia channels, respectively. 137Cs failed to use for the validation of the established chronologies, while its inventories found 450 Bq.m-2 and 355 Bq.m-2 in the Sicily and Sardinia channel, respectively.

Reconstructing Bioinvasion Dynamics Through Micropaleontologic Analysis Highlights the Role of Temperature Change as a Driver of Alien Foraminifera Invasion

“…While the absence of the Chernobyl peak of 137 Cs is common in sediments collected in the southern part of the Mediterranean Sea due to the dispersion pattern of 137 Cs fallout that followed the accident, it is surprising to have no signal of nuclear bomb experiments. Nevertheless, the absence of 137 Cs in both cores supports the finding that in this area the 137 Cs supply is negligible, as also reported by other works (e.g., Hassen et al, 2019).…”

Crustal deformation, active tectonics and seismic potential in the Sicily Channel (Central Mediterranean), along the Nubia–Eurasia plate boundary

“…However, we note that in the depocenters, H1 is located about 1 s two-way-time below the seafloor, roughly corresponding to about 1 km of depth. Considering a constant sedimentation rate of 1 mm/year, as deduced for the uppermost sedimentary sequence by radiometric dating 46 , this level might be dated back to about 1 Ma. This estimate, although very rough, agrees with chrono-stratigraphic and biostratigraphic reconstructions carried out in the Gela basin, where the more recent depositional sequence boundaries were dated to 1.4 Ma (Early Pleistocene) and 0.8 Ma, during a peak of the regression 43 , 47 .…”

Sedimentary carbon on the continental shelf: Emerging capabilities and research priorities for Blue Carbon

“…Alternatively, 210 Pb can also be determined indirectly by measuring polonium-210 ( 210 Po), its granddaughter decay product, via alpha spectrometry. Although this alternative traditional radiometric technique requires samples to be digested in strong acid mixtures and treated prior to analysis, the limits of detection and level of accuracy and precision that can be achieved are more appropriate (Hassen et al, 2020). The underlying assumption, that 210 Pb is in secular equilibrium with 210 Po such that both radionuclides are present at the same concentration, can be verified by performing a second analysis of 210 Po at a later stage, i.e., generally, by determining 210 Po ingrowth from the decay of 210 Pb after three to four months.…”