Geochemistry and the Biosphere. Vladimir I. Vernadsky
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The notion of geochemistry as a science about the history of terrestrial atoms appeared as a background to the new atomistics, chemistry and physics, in close connection with the idea of mineralogy typical of the Moscow University in 1890–1911. Both in teaching and in scientific mineralogical work there, most attention was paid to the history of minerals – their genesis and their change – which usually occupied a second rank in the mineralogy of schools of higher education at that time. With such a presentation of mineralogy, geochemical problems were presented on a larger scale, and were considered more important15 than in the common university courses of inorganic chemistry. Gradually, the work of the Mineralogy Chair of the Moscow University, and later the work related to it at the Mineralogy Museum of the Academy of Sciences, was more and more directed toward geochemistry. The name given by Clarke immediately found content here (although different from his own) and fruitful ground. The phenomena of life, and the mineralogy of sedimentary rocks in connection with radioactivity and general issues concerning the properties and character of atoms, occupied a considerable place. In 1912 in Moscow, in the university named after Shaniavsky, A. E. Fersman delivered the first university course of this new science. Furthermore, a series of A. E. Fersman’s and Ya. V. Samoylov’s works (1870–1925) have firmly established the traditions of geochemical work in our country.
By the twentieth century, the study of ore deposits, which had made great progress by that time, contributed greatly to the creation of geochemistry. The close connection between geochemical problems and insights about ores, which had led to the generalizations of Bischof, Breithaupt, and Elie de Beaumont in the previous century, has never been interrupted. But in the new century it acquired quite a different appearance due to the progress of chemistry, the unusual deepening of technology, and the great scope of extracting old metals and introducing new metals into the structure of human economy and life. In our century this phenomenon has acquired an extraordinary form: that of the global economy.
The works of the Frenchman, L. de Launay, and the German, A. Stelzener (1840–1895), were of great influence and posed geochemical problems. But considering the problems of the theory of ore deposits or applied mineralogy, most significant in the creation of the field of geochemistry are the works of the Norwegian, I. Focht (1858–1932), which are closely connected with the century-long mineralogical research based on the nature of Fennoscandia, and the works of North American mining engineers such as C. Van Hise and W. Lindgren. They connected the problems of geochemistry to that of ores, and in this way gave it a great practical value. This applied significance of geochemistry is growing rapidly during recent years. It manifests itself in our country as well, but we have to say that the conditions for its correct development are not favorable here.
Modern geochemistry is closely connected with the work and thought of another scientist – Prof. V. M. Goldschmidt – who in 1930 created the most powerful scientific center of geochemical work in Göttingen, Germany, although he himself was a product of the century-long scientific traditions of the Norwegian school of mineralogy. From 1914 to 1930, V. M. Goldschmidt, disciple of the outstanding mineralogist V. Brögger, was a professor in Christiania (now Oslo), where he created a mineralogical and geochemical institute with a high level of scientific thought. The Institute of Göttingen made further progress. The nature of Fennoscandia gave the mineralogical work in that country quite a unique flavor; it is an area of ancient crystalline rocks, and radioactive minerals are also present.
Often they are quite unusual in beauty and manifestation, distinctly different from all others in their outer form, unique in color, shine, and chemical composition, and also in such physical properties as metamic structures, compounds of uranium and thorium, rare earths, titanium, niobium, tantalum, zirconium, and hafnium. The school of chemists and mineralogists, which was here for centuries, covered this most difficult group of terrestrial bodies and discovered in the native material a quantity of new minerals and new elements. Bercelius, proceeding from this native material, applied his thought and exact methods to the whole area of inorganic chemistry of the twentieth century.
At the end of the century, Brögger synthesized the mineralogical work of the Fennoscandian and German scientists with reference to the same natural bodies. W. C. Brögger (born in 1851), a man of rare knowledge and exactitude of work, is equally prominent in geology, paleontology, and crystallography. He is a first-class researcher both in the field and in the laboratory; he connected the chemical study of minerals with their crystalline structure, developing in this field the ideas of another Norwegian scientist, the chemist and mineralogist T. Hjortdal (1839–1925).
Brögger’s disciple, V. M. Goldschmidt, therefore approached geochemical problems in surroundings full of traditions. The deeper geospheres of the Earth’s crust that are located beyond the stratisphere and the biosphere drew his attention; they constitute the largest part of the substance of our planet open to research. Solid matter acquired a special significance, and due to a new specification of roentgenometric methods, led to creation of crystal chemistry, in which Goldschmidt played an important role. Working in this direction, and taking into consideration the processes of elements’ migrations in the vectorial solid medium, Goldschmidt introduced into geochemistry a notion fraught with many consequences: the notion of the chemical elements’ behavior, as conditioned by their structure. He pointed out the regularities of their manifestation in the solid medium forming the Earth’s crust. Goldschmidt’s Institute in Göttingen is at present the largest center for this kind of scientific work.
Geochemistry is developing rapidly now; its influence and significance in purely scientific issues is constantly growing and increasing. The preparatory period is over. Separate branches are beginning to spring up thanks to the close connection of the large complex of its problems with fields that are in fact separated from geological disciplines, one of which is geochemistry. In this way, biogeochemistry has begun to separate. In 1927, the center for research in this field was established in Russia at the Academy of Sciences: its Biogeochemical Laboratory, which is not very powerful as yet.16
table 1
Table I Periodic Table of the Elements. [This is a modern version, included for reference. It is a far cry from the original version by Mendeleyev, Vernadsky’s professor. Elements in italics have been created in laboratories of nuclear physics; all are highly radioactive. The names of these are interesting: After honoring Greek gods, places, and scientists, the namers apparently gave up with #104 and used a numbering system. Ed.]
chemical elements in the earth’s crust; their forms of existence and classification
1 geochemistry classification of chemical elements
The first question that appeared in geochemistry was that of the number of bodies subject to its study: i.e., the number of different chemical elements and atoms that exist or possibly exist in the Earth’s crust. At present we can only investigate this problem as far as it concerns the surface layer of the Earth. As for this area, the question can be answered definitely enough. In general, taking into account only the isotopes we know, and not the possibly existing ones, we can state more than 200 different compositions of atoms, corresponding to the 92 atomic numbers – N. Moselli’s numbers – in the Periodic Table of D. I. Mendeleyev (table 1).
Within the limits of Mendeleyev’s table, all the representatives of its 92 atomic numbers are apparently known; they are either isolated, or their existence on our planet is confirmed by exact data. But it is possible that in the world – on our planet – there are several elements that are not covered by this table elements lighter than hydrogen, for which Moselli’s number is one, or heavier than uranium, which has atomic number