EXPERIMENTAL MODELING OF SR COPRECIPITATION WITH CA CARBONATE IN THE MOUTHS OF RIVERS

Abstract

The experimentally determined Sr partition coefficients between CaCO 3 and solutions that imitate the water in river mouths are consistent with the available literature data on the Sr partition coefficients for aragonite. These values are equal to 0.91 for fresh water and decrease to 0.72 for the water of the northern Caspian Sea with a salinity of 11.8‰ and to 0.53 for normal seawater with a salinity of 35‰. The origin of autochthonous CaCO3 in river mouths is demonstrated to only insignificantly affect the dissolved Sr flux and can be associated with only week Sr and Ca fractionation. Conversely, the formation of carbonates in seawater plays the decisive role in the increase in the Sr/Ca ratio compared to that in river water.