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Titel |
Gateway restriction and climatic conditions of the Mediterranean Sea during the Messinian Salinity Crisis; A box model including Sr-isotope ratios |
VerfasserIn |
Robin Topper, Paul Meijer, Rachel Flecker, Rinus Wortel |
Konferenz |
EGU General Assembly 2010
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Medientyp |
Artikel
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Sprache |
Englisch
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Digitales Dokument |
PDF |
Erschienen |
In: GRA - Volume 12 (2010) |
Datensatznummer |
250038986
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Zusammenfassung |
Under certain conditions the ratio of two stable isotopes of strontium present in the water of a
semi-enclosed basin (87Sr/86Sr) is known to be sensitive to the relative size of the inflow of
ocean water and river input. Combining Sr-isotope ratios measured in Mediterranean Late
Miocene successions with data on past salinity, Flecker et al. (EPSL, 203, 221-233, 2002)
and Flecker and Ellam (Sed.Geol., 188-189, 189-203, 2006) were able to derive quantitative
information on the Mediterranean hydrological budget at times before and during the
Messinian Salinity Crisis (MSC). The authors obtained this hydrological budget by inverting
the salinity and strontium data with steady-state solutions to the conservation equations of
salt, strontium and water.
In this study, we incorporate strontium concentration, Sr-isotope ratio and a Late Miocene
water budget from Gladstone et al. (P3, 251, 254-267, 2007) in the box model from Meijer
(EPSL, 248, 486-494, 2006) which quantifies the water and salt budget of the basin under
specified conditions of connectivity with the Atlantic Ocean, representing tectonic restrictions
of the Rifian and Betic gateways, and atmospheric fluxes, induced by climatic changes.
This model will give insight in the coeval behaviour of salt and Sr-isotope ratios
under changing contributions of ocean and fresh water. With respect to the model of
Flecker et al. (2002) the extended model is a significant advancement as it allows for
examination of the temporal evolution of salt and Sr-isotope ratio as a function of the
individual hydrologic fluxes (Atlantic inflow and outflow, river input and evaporation,
instead of the inflow and outflow parameters used by Flecker et al. (2002)), and the
possibility of non-equilibrium states during the Late Miocene. Model evaluation
is performed using the Sr-isotope ratio data set compiled by Flecker and Ellam
(2006).
Results from our model have implications for the timing and extent of Late
Miocene Atlantic gateway restrictions and climatic changes (expressed as changes in
evaporation and river input) and hence for scenarios for pre-MSC and MSC intervals. |
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