[MIS07-17] Field investigation on capturing of lake water salts within surface ice on ice-covered saline lakes in Mongolia: Implications for icy shell compositions of Solar System icy bodies.
Keywords:Icy bodies, Surface evolution, Interior evolution
Here, we report results of field survey to ice-covered lakes, the Orog and Olgoy lakes, in Mongolia to investigate water capturing within ice upon freezing. These lakes are saline closed-basin lakes. The surface is completely covered with ice in winter. Upon freezing, surface ice can be pressurized due to volume expansion of the ice, possibly forming cracks and fractures within the ice.
We performed field surveys to these lakes in February 2019 and January 2020. We collected the ices and underlying lake water at different locations of the lakes. The obtained vertical profile of salt contents and their mineral compositions from the ice samples are compared with our calculation results of brine capturing model coupled with low-temperature aqueous geochemical model. From the comparison, salt contents at the bottom are several times higher than calculation of brine captured model. We discuss about possibilities which can produce this variation of vertical profiles about salt contents (e.g. crack formation). We also argue the effect of trapped salt within icy crust to surface and interior evolution in icy bodies.