Open AccessPrecessional control of Sr ratios in marginal basins during the Messinian Salinity Crisis?
Author(s) -
Topper R. P. M.,
Lugli S.,
Manzi V.,
Roveri M.,
Meijer P. Th.
Publication year - 2014
Publication title -
geochemistry, geophysics, geosystems
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.928
H-Index - 136
ISSN - 1525-2027
DOI - 10.1002/2013gc005192
Subject(s) - geology , salinity , structural basin , precession , forcing (mathematics) , mediterranean climate , mediterranean sea , mediterranean basin , oceanography , geomorphology , climatology , ecology , physics , astronomy , biology
Based on 87 Sr/ 86 Sr data of the Primary Lower Gypsum (PLG) deposits in the Vena del Gesso basin—a marginal basin of the Mediterranean during the Messinian Salinity Crisis—a correlation between 87 Sr/ 86 Sr values and precessional forcing has recently been proposed but not yet confirmed. In this study, a box model is set up to represent the Miocene Mediterranean deep basin and a connected marginal basin. Measurements of 87 Sr/ 86 Sr in the Vena del Gesso and estimated salinity extrema are used to constrain model results. In an extensive analysis with this model, we assess whether coeval 87 Sr/ 86 Sr and salinity fluctuations could have been forced by precession‐driven changes in the fresh water budget. A comprehensive set of the controlling parameters is examined to assess the conditions under which precession‐driven 87 Sr/ 86 Sr variations occur and to determine the most likely setting for PLG formation. Model results show that precession‐driven 87 Sr/ 86 Sr and salinity fluctuations in marginal basins are produced in settings within a large range of marginal basin sizes, riverine strontium characteristics, amplitudes of precessional fresh water budget variation, and average fresh water budgets of both the marginal and deep basin. PLG deposition most likely occurred when the Atlantic‐Mediterranean connection was restricted, and the average fresh water budget in the Mediterranean was significantly less negative than at present day. Considering the large range of settings in which salinities and 87 Sr/ 86 Sr fluctuate on a precessional timescale, 87 Sr/ 86 Sr variations are expected to be a common feature in PLG deposits in marginal basins of the Mediterranean.