Abstract

The conditions for magnesium fluoride (sellaite) precipitation from seawater with a salinity of 35–105‰ were experimentally determined. It was found that the precipitation of MgF₂ at the salinity of 35, 70, and 105‰ occurs at a concentration of dissolved fluorine above 37, 46, and 51 mg/L, respectively. In isolated evaporite basins, the fluorine concentration required for the formation of sellaite is not reached at all stages of the evaporative thickening of seawater. Therefore, it is assumed that a high concentration of fluorine, sufficient for the precipitation of sellaite, arises as a result of the combined effect of evaporation and additional input of this element into salt-bearing basins with river runoff and/or the release of coprecipitated and sorbed fluorine during the post-sedimentary recrystallization of salt minerals.

中文翻译：

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盐沉积物中硅藻土的形成条件

摘要

实验确定了从盐度为35-105‰的海水中析出氟化镁（硅藻土）的条件。MgF _2的沉淀在 35、70 和 105‰的盐度下，溶解氟浓度分别高于 37、46 和 51 mg/L。在孤立的蒸发岩盆地中，并非在海水蒸发增稠的所有阶段都达到形成硅镁石所需的氟浓度。因此，假设高浓度的氟足以沉淀出硅藻土，这是由于蒸发和该元素额外输入到河流径流的含盐盆地和/或共沉淀物的释放的综合影响而产生的。并在盐矿物的沉积后重结晶过程中吸附氟。