Heterogeneous Processes of Geochemical Migration

The problem of the geochemical migration of elements has received wide attention in the works of V. I. Vernadskii and A. E. Fersman [1, 2J. Vernadskii considered geochemistry to be the science of the history of chemical elements on the earth, their distribution and move­ ments in space and time, and their genetic relations [IJ. Geochemical migration was defined by Fersman as "the movement of chemical elements in the earth's crust leading to their dissemination or concentration. " The views of Vernadskii and Fersman on the migration of elements have received added support and development in connection with successes in physics, chemistry, biology, and other sciences. According to Fersman, the earth is looked upon as a cosmic body, characterized by common origin and Similarity of composition with the sun, the planets, meteorites, and other bodies of the solar system. The scale and trend of geochemical migration of elements in the earth are determined by the initial state of terrestrial matter, its thermal history, and the scale of time. The rules of elemental migration are determined by internal and exterual fac­ tors. Fersman distinguishes five groups of internal factors, i. e.

1. Formulating the Problem of the Geochemical Migration of Included Substances, and Methods of Solving It.- § 1. Formulating the problem of geochemical migration of included substances.- § 2. Equations of material balance and kinetics of the processes of interaction between a substance and host rocks.- § 3. Hydrodynamic equations.- § 4. Simplification and methods of solving the problem.- § 5. The geochemical migration of mixtures.- Literature cited.- 2. Diffusion in Rocks.- § 6. Laws of diffusion.- § 7. Solutions of diffusion equacions for steady-state current.- § 8. Solutions of the linear equation of nonstationary diffusion for an unbounded body.- § 9. Solutions of the linear equation of nonstationary diffusion for a semibounded body.- § 10. Solutions of the diffusion equation for a finite body.- § 11. Factors affecting the coefficient of diffusion.- § 12. Aspects of diffusion in rocks.- § 13. Methods of determining coefficients of diffusion in rocks.- § 14. Description of the diffusion of salt in rocks.- § 15. Experimental data on the diffusion of salt in rocks.- § 16. The effect of moisture content on the diffusion of salt in rocks.- § 17. Experimental data on the diffusion of gases in rocks.- Literature cited.- 3. Adsorption and Ion Exchange in the Interaction of Solutions and Gases with Rocks.- § 18. The concept of adsorption.- § 19. Adsorption isotherms of gases and vapors on a homogeneous surface.- § 20. Adsorption of gases and vapors by porous adsorbents.- § 21. Adsorption of solutions on the surface of solids.- § 22. Ion exchange.- § 23. The concept of chemisorption.- § 24. Ion-exchange equilibrium in soils.- § 25. Investigation of adsorption and ion exchange in rocks.- § 26. Adsorption of gases on rocks.- Literature cited.- 4. The Kinetics of Adsorption, Ion Exchange, and Chemical Reactions of Solutions and Gases with Rocks.- § 27. The basic aspects of formal kinetics.- § 28. Heterogeneous processes.- § 29. Kinetic and diffusion regions of heterogeneous chemical reaction.- § 30. The kinetics of adsorption and ion exchange.- § 31. Equations of internal-diffusion kinetics of adsorption and ion exchange.- § 32. The effect of temperature on reaction rate.- § 33. Methods of studying the kinetics of heterogeneous processes.- § 34. Experimental data on the kinetics of heterogeneous processes in rocks.- Literature cited.- 5. The Kinetics of Adsorption, Ion Exchange, and Chemical Reaction in a Current.- § 35. The kinetics of adsorption and ion exchange in the external-diffusion region.- § 36. The kinetics of adsorption and ion exchange in the internal-diffusion region.- § 37. The kinetics of adsorption and ion exchange with simultaneous consideration of intergranular and intragranular diffusion.- § 38. The kinetics of adsorption and ion exchange due to flow.- § 39. Determination of the diffusion mechanism controlling the rate of adsorption and ion exchange.- § 40. The kinetics of heterogeneous chemical reactions in a current.- § 41. Study of the kinetics of ion exchange in rocks from a current.- Literature cited.- 6. Geochemical Migration Due to Filtration and Diffusion.- § 42. Diffusion in a heterogeneous medium with consideration of adsorption and ion exchange.- § 43. Diffusion in a heterogeneous medium, considering chemical reactions.- § 44. Filtration in a heterogeneous medium in the absence of interaction between substance and medium.- § 45. Filtration of a one-component solution in a porous medium, considering adsorption and ion exchanges.- § 46. Geochemical migration due to filtration in a weakly adsorbent medium.- § 47. Filtration in a heterogeneous medium with consideration of chemical reaction.- § 48. Filtration of a mixture of substances.- § 49. A dynamic method of determining the kinetic coefficients of adsorption and ion exchange.- § 50. Experimental results on filtration of solutions not interacting with the rocks.- § 51. A study of diffusion and filtration of adsorbable solutions and gases in rocks.- § 52. The so-called “filtration effect”.- Literature cited.- 7. The Theory of Formation of Hydrothermal Deposits and Geochemical Aureoles at Deposits of Ores and Gas.- § 53. The formation of hydrothermal deposits and primary aureoles by interaction between solution and country rock.- § 54. The formation of deposits by reaction between components of hydrothermal solutions.- § 55. The theory of forming secondary geochemical aureoles of ore and gas deposits.- § 56. The question of oil formation.- Literature cited.