包头地区氟的表生地球化学

HYPERGENIC GEOCHEMISTRY OF FLUORINE IN THE REGION OF BAO TOU, CHINA

Chemical analyses of water and soil samples from the region of Bao Tou, and chemical equilibrium calculations indicate a large amount of water-soluble fluorine accumulating in the surface soil, giving rise to ground water with high fluorine during the process of soda-salinizatiun. Thermodynamic calculations of ground water from the region of Bao Tou show: △GaCO3>△GC2F2 >△GCaSO4,, leading to the following sequence in respect to fluorine: CaCO3→CaF2→Ca8O4. But during the process of sodasalinization the sequence should be: CaSO4→NaF→ NaCl. Ground water saturated with fluorine is generally related to water-soluble fluorine-rich sediments of the Middle-Pleistonce series, the distribution of which is controlled by new tectonic movement on one hand,and controls the distribution of endemic fluorosis on the other hand.

Chemical analyses of water and soil samples from the region of Bao Tou, and chemicalequilibrium calculations indicate a large amount of water-soluble fluorine accumulating in thesurface soil, giving rise to ground water with high fluorine during the process of soda-sali-nization. Thermodynamic calculations of ground water from the region of Bao Tou show: ΔG_(CaCO_3)>ΔG_(CaF_2)>ΔG_(CaSO_4), leading to the-following sequence in respect to fluorine: CaCO_3→CaF_2→CaSO_4. But during the process of sodasalinization the sequence should be: CaSO_4→NaF→NaCl. Ground water saturated with fluorine is generally related to water-soluble fluorine-richsediments of the Middle-Pleistonce series, the distribution of which is controlled by newtectonic movement on one hand,and controls the distribution of endemic fluorosis on theother hand.