Quantification des flux sédimentaires et de la subsidence du bassin ...

tel-00790852, version 1 - 21 Feb 2013
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To calculate the evaporite thickness, it is necessary to know the water volume and the salt
concentration. The salinity of the Mediterranean at the beginning of the crisis C0 is considered
to be 35 g/l, equal to the salinity of the Atlantic Ocean Cocean. The salinity of rivers Criver is
assumed to be of 1 g/l. The salt concentration of the Western Mediterranean Basin at time t is
therefore given by:
C(t) = [M0 + Mriver (t) + Mocean(t)] / V(t)
where V(t) is the volume of the sea water at the time t and M0 = C0.V0 is the mass of
evaporites when all the water in the Western Mediterranean is evaporated. Mriver(t) =
Qriver(t).Criver.t is the mass of evaporites which come from river discharge Qriver,
Mocean(t)=Qocean .Cocean . t is the mass of evaporites which come from the Atlantic Ocean
through an oceanic inflow Qocean when Atlantic waters overflooded the Gibraltar sill. The salt
precipitates when C(t) >130 g/l. This precipitation allows the formation of evaporite minerals.
The salt density used to calculate the volume of evaporites is 2170 kg/m 3 .
10. Acknowledgments
We thank Bertrand Meyer, Vaughan Stagpoole and Bilal Haq for critical discussions and
reading of a preliminary version of the manuscript. We thank TGS-Nopec and Total for
making their data available and in particular Jacqueline Camy-Peyret (Total) for her help in
working with the database.
11. References cited
Abd Ellah, R.G., 2009. Evaporation rate at Wadi El-Rayan Lake, Egypt. World Applied
Sciences Journal 6, 524-528.
Alhammoud, B., Meijer, P., Dijkstra, H.A., 2010. Sensitivity of Mediterranean thermohaline
circulation to gateway depth: A model investigation. Paleoceanography 25, PA2220.
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