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Advances in geochemistry during the last four decades: A personal perspective
Applied Geochemistry 24 (2009) 1048–1051
Contents lists available at ScienceDirect
Applied Geochemistry journal homepage: www.elsevier.com/locate/apgeochem
Advances in geochemistry during the last four decades: A personal perspective Eric M. Galimov V.I. Vernadsky Institute of Geochemistry and Analytical Chemistry, Moscow, Russia
a r t i c l e
i n f o
Article history: Available online 10 March 2009
a b s t r a c t This is the author’s speech at the meeting in Cologne (2007) to celebrate the 40th anniversary of the International Association of Geochemistry and Cosmochemistry, which the author served as the President in 2000 to 2004. The paper narrates the author’s personal involvement in important scientific programs during the last 4 decades, including implementation of isotope techniques, oil-and-gas research, diamond research, deep-sea drilling, space research, molecular biology and the origin of life. Ó 2009 Elsevier Ltd. All rights reserved.
1. Influence of isotopic methods on the development of geological sciences in the 20th century In 1966, Academician A.P. Vinogradov, the author’s teacher, who was at the time Director of the V.I. Vernadsky Institute of Geochemistry and Analytical Chemistry, organized the USSR’s first Symposium on Stable Isotopes. The author was tasked to present a plenary paper on C isotopes. Carbon is an element that forms the basis of life and is contained in some of the Earth’s most important mineral products such as oil, natural gas, coal and diamonds. Some data presented in that paper are worth mentioning here. The value of the average isotope composition of Earth’s crustal C was calculated by the author to be d13C = 5‰; this figure has been accepted as valid up to the present day. Also, the hypothesis was made that ocean water and organic C were produced due to fallout of materials similar to carbonaceous chondrites on the Earth at a later stage of its accumulation. This idea became popular in the published literature years later. In 1967, the author wrote a book titled Geochemistry of Stable Carbon Isotopes that summarized the initial stage of research in this field (Galimov, 1968). In the decades 1960 and 1970 extensive studies of oil and gas in the USSR were carried out using isotopic techniques. It was realized very soon that data interpretation was impeded by inadequate background on the isotope chemistry of organic compounds. Indeed, geochemistry of isotopes can only become a serious science when it is based on a system of thermodynamic and kinetic constants. Otherwise, it is simply a primitive empiricism. Early in the 1960s, theoretical coefficients of isotope separation (b-factors, as they were called) were only known for simple C compounds, such as CH4, CO and CO2, and for single-C crystals (diamond and graphite). As oil and gas were being dealt with at that time there was interested in calculating the isotopic constants for hydrocarbon systems. The b-factors for hydrocarbons were calculated in the author’s laboratory: alkanes up to pentane, cyclohexane, benzene, toluene, and then for acetate aldehyde, acetic acid, methylE-mail address: [email protected] 0883-2927/$ - see front matter Ó 2009 Elsevier Ltd. All rights reserved. doi:10.1016/j.apgeochem.2009.02.020
amine and some other organic compounds (Galimov and Ivlev, 1973; Galimov, 1973a). In so doing, the isotopic thermodynamics of complex organic compounds was developed, taking account of the non-equivalent position of different C atoms in organic molecules. The notion of an intramolecular isotope effect was introduced (Galimov, 1971). The author suggested a method, which became known as the ‘method of the isotopic bond numbers’, that facilitated a close approximation to the b-factor of highly complex C compounds (Galimov, 1973b, 1985). From theory, it was determined that the isotope effect depends on the band of activation energy, e.g., it is different for CH4 formed from kerogen and from a single component (Galimov, 1974). This work later proved to be important for the understanding of mechanisms of natural gas formation (Galimov, 1988). 2. Industrial development and the growth of production and use of hydrocarbon raw materials and fuels It is quite understandable that oil and gas geology became at the time a most important area of application for new isotopic methods. Several results related to the activities in that field will now be cited: (1) The author’s group suggested the oil–oil correlation and oil-source rock identification methods based on comparison of isotope compositions of the corresponding fractions extracted from oil and the organic matter of the putative oil-source beds (Galimov and Frik, 1985; Galimov, 1986). Identification of oilsource beds significantly increases the reliability of predicting the hydrocarbon reserves in sedimentary basins. The method was successfully applied in many oil fields of the former USSR. (2) It was shown that isotopic composition of CH4 depends on maturity of the gas source organic matter (Galimov, 1973a; Galimov et al., 1973). This dependence has served as an effective tool in the search for gas source rocks both in Russia and abroad. (3) It was demonstrated that the main bulk of hydrocarbons and biological markers contained in oil have a common line of isotope fractionation, which unequivocally indicates the organic origin of oil (Bogacheva and Galimov, 1979; Galimov, 1985). (4) Analysis of hydrocarbons
E.M. Galimov / Applied Geochemistry 24 (2009) 1048–1051
contained in minerals of igneous rocks showed that they have isotopic characteristics that are fundamentally different from those of hydrocarbons in sedimentary rocks (Galimov and Petersilie, 1967). (5) A vast number of oils, individual hydrocarbons, and oil fractions from many fields in the Volga-Ural region, western and eastern Siberia, Caucasus, Central Asia, and the Far East were analyzed. At the time, it was probably the most comprehensive collection of data on the isotopic composition of C in oil and gas that existed anywhere in the world. These data were summarized in a monograph Carbon Isotopes in Oil and Gas Geology (Galimov, 1973a). By the end of the 1980s, a general model of isotope fractionation in hydrocarbon gas was developed that took into account the differences between distribution functions of activation energies for organic matter of different types and structures (i.e., sapropelic and humic). This model was based on the theoretical work already mentioned on the dependence of isotopic composition on the activation energy band. It allowed interpretation of the origin of the giant gas accumulations in Cenomanian deposits of western Siberia that amount to 30% of the world’s gas resources. In general, the possibility of CH4 generation at an earlier stage of transformation of humic organic matter that was demonstrated did much to establish search criteria and prospects for evaluation of new gas-bearing territories (Galimov, 1988). The methods that are useful for oil and gas exploration have been developed on the basis of the systematic study of isotope fractionation processes on the way from living to fossil forms of organic substances (Galimov, 1980, 1995, 2006a). 3. Diamonds and economic development in the latter half of the 20th century The author was once amazed to read in a book a phrase stating that the economic potential of the USA would fall by about 1/3 if all diamonds were to be extracted from all tools in operation. In the USSR, diamond-related research activities were stimulated by the discovery of diamond-rich kimberlitic pipes in eastern Siberia. Isotopic analysis of C is a direct and profound method to investigate the nature of diamonds. Thousands of diamond crystals were analyzed in the author’s laboratory. The bulk of data produced by the end of the 1970s constituted some 90% of all isotopic data obtained for diamonds by laboratories around the world. The result of this work was to establish the fundamental laws of the distribution of C isotopes in diamond crystals with respect to deposit type, mineral paragenesis, crystal morphology, etc. (Galimov, 1984, 1991). Most remarkable was the discovery of the isotopically-light diamonds. It was totally unexpected to find such a wide range of Cisotope variation for such a high-temperature mineral. Also, an important observation was the principal difference in composition of diamonds of ultrabasic and eclogitic genesis, found in all diamond deposits. In 1973, a theoretical paper was published on possible diamond formation during the process of cavitation in an ascending kimberlite melt (Galimov, 1973c). Cavitation results from the collapse of gas bubbles as a liquid moves along a channel of variable cross-section. Cavitational formation of diamonds in kimberlitic liquid as it bursts out from the mantle offered an explanation for many diamond properties. Recently, the author’s group managed to produce diamonds by inducing cavitation in a laboratory experiment (Galimov et al., 2004). 4. Revolutionary changes in geological sciences due to research on the deep ocean floor The initiation of the ocean deep-sea drilling project (DSDP and, afterwards, ODP) opened a new window to the geology beneath the sea. Up to the early 1960s, hundreds of thousands of wells
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had been drilled in the continents, and none in the ocean. In 1976, the author participated in an expedition of the Glomar Challenger drill-ship, the flagship of ocean floor research. During Leg 50, as well No. 415 was being drilled, the re-entry procedure (repeated entering of a hole drilled in ocean floor) was attempted for the first time. Before that, drilling in bottom sediments would continue only until the drill bit wore out, which normally happened at a depth of 300–400 m. In order to replace the bit with a new one, the pipe string with the bit attached end had to be withdrawn, afterwards to be sunk again through many meters of water, exactly hitting a 10–15 cm diameter spot on the ocean floor. It was in 1976 that this procedure was successfully carried out up to 12 times using specially-designed devices. As a result, the deepest bore hole of the DSDP project (1700 m deep) was drilled. Analysis of the extracted core was undertaken initially by the organic geochemistry group aboard the vessel and then continued in detail in the author’s laboratory in the Vernadsky Institute. It was from this work that the evolution of chemical and isotopic composition of organic materials and gases along the entire depth range of sedimentary strata of the ocean was established (Galimov et al., 1980). Later on, the author took part in many nautical expeditions. One of the most fruitful cruises was the 14th run of the R/V Academician Boris Petrov carried out in 1990, which studied the H2S generating basins in the Atlantic Ocean (Cariaco), in the Mediterranean (Bannok), and in the Black Sea. In 1992, the author had occasion to work aboard the JOIDES Resolution, a more powerful American drill-ship that replaced the Glomar Challenger. The cruise traversed from north to south across the sedimentary layer of the equatorial zone of the Pacific. As a result, material was obtained that became the basis of a paper on global changes in isotopic composition of C related to climatic changes during the Cenozoic (Galimov, 1996, 1999). Detailed investigations in biogeochemistry, radiochemistry, and organic chemistry of marine sediments were also carried out in the ship, the Academician Boris Petrov, in the Arctic basin (Kara Sea) (Galimov et al., 1996). During the 1999 Antarctic passage of the Academician Boris Petrov, the author landed on islands in sub-Antarctic archipelagoes to gather mosses and lichens; later, a paper was published on the peculiar features of C composition in sub-Antarctic plants (Galimov, 2000). The last cruise that the author took part in was during November 2006, and was aimed at the search for gas hydrates in the Indian Ocean. The author has always been interested in the problem of gas hydrates, and several publications address this topic (Galimov and Shabaeva, 1985a,b; Galimov and Kodina, 1982; Galimov, 2006a). One of the conclusions, drawn as early as the beginning of the 1980s, is that gas hydrate accumulations in the ocean can only be relevant when they are related to gas inflow from deeper (more than 2–3 km deep) sea floor sediments, i.e., only in regions where such sediments and structures exist. Ocean research was one of the most fascinating enterprises in geology and geochemistry during the latter half of the 20th century. The author is happy that he could be directly involved in it. 5. Breakthroughs in our scientific knowledge resulting from studies of the Moon and planets The author had the chance to witness the epoch of Sturm und Drang in this field that took place during the 1960s and 1970s. The Vernadsky Institute, where the author worked, was at the centre of this research. The author’s group analyzed the C-isotopic composition in lunar soil returned by the Soviet Luna-16 automated probe in 1972. One should note, however, that by this time, analyses had previously been made on the lunar samples returned by the Apollo 11 to Apollo14 missions.
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The author has always been interested in the problem of the origin of the Moon. The hypothesis of Moon formation as a result of collision of the Earth with another planetary body, as put forward by Hartmann and Davis (1975) and Cameron and Ward (1976), was never satisfying. In this case, 80% of the Moon would have had to have been formed out of a foreign planetary body of unknown origin, rather than from Earth material (Canap, 2004). This did not agree with the absolute coincidence of fractionation lines of isotopic composition of the Earth and the Moon at the 3-isotope-oxygen diagram, which suggested a complete unity of the initial reservoir of the Earth and the Moon. There were other objections as well. That is why my research group began to develop an alternative chemical and dynamic model for Moon formation. It was demonstrated that the Moon and the Earth could be formed out of a common reservoir, a dust cloud that was produced within the circumsolar nebula at the earliest stage of formation of the Solar System (Galimov et al., 2005). The main idea of the hypothesis was that the dust particles were heated and partly evaporated during cloud contraction. Evaporation ensured the appearance of a repulsion force that could easily account for the advent of fragmentation at the angular momentum of the dust cloud, smaller than the momentum of the present Earth–Moon system. A model involving evaporation within the cloud could also explain the loss of volatiles without isotope fractionation, which the giant-impact model failed to explain. Finally, as it turned out, evaporation could also explain the loss of Fe and, consequently, the observed deficit of Fe in the Moon (Galimov, 2004b). Computer simulation demonstrated that, at the suggested conditions, fragmentation of a dust cloud does develop, and two condensations are formed that can be considered embryos of the Earth and the Moon. When addressing the problem of the origin of the Moon, it is important to have information on its inner structure, the size of the core, and the chemical composition of the mantle. In 1995, the author put forward a project of a space mission to the Moon aimed at investigating its inner structure. The project passed the preliminary development stage and became known under the name of Luna-Glob (Galimov et al., 1999) Launch of the spacecraft is now included in the Russian Federal Program and is scheduled for 2012. It includes special seismic experiments, to be carried out with penetrators. It is hoped that carrying out the project will allow the solution of the problem of the origin of the Moon, which is also important for reconstruction of early Earth history. The Russian Federal Program also includes another planetary research project named Phobos-Grunt (Galimov, 2006b). The Phobos-Grunt mission involves recovering samples from Phobos (a satellite of Mars). Launch of the spacecraft is scheduled for 2009. Fragments of material from Mars, known as SNC meteorites, are present on Earth. Comparing their composition with that of the samples brought back from Phobos will allow the question to be answered as to whether Phobos is related to the Martian reservoir or is an alien body captured by Mars.
6. Isotopes, molecular biology, and the origin of life One of the most paradoxical phenomena that the author has managed to discover is a specific feature of isotope fractionation in biological objects (Galimov, 1973d, 1985; Galimov and Shirinsky, 1975; Bogacheva and Galimov, 1979; Meinschein et al., 1984; Schmidt, 2003). The method of ‘isotopic bond numbers’, developed to calculate b-factors of biochemical components: lipids, proteins, and carbohydrates, was used. Measured isotopic composition of biological compounds was found to correlate to calculated values of their respective b-factors. It should be emphasized that this correlation is characteristic of biological compounds and is not to be found in analogous compound of non-biological
nature. The paradoxicality of this observation lies in the fact that the b-factor characterizes the equilibrium state. Correlation between measured isotopic compositions and b-factors is only observed in systems that are close to equilibrium. How then can one make this agree with the seemingly absolute non-equilibrium character of living systems? It has been demonstrated that such extraordinary distribution of isotopes is caused by the fact that all biosynthesis reactions in an organism are carried out and controlled by enzymes (Galimov, 1985, 2007; Galimov and Polyakov, 1991). It involves a reversible substrate-to-product transformation that takes place in the enzyme–substrate complex. Individual biochemical reactions are close to equilibrium, and the observed chemical non-equilibrium of biosystems is determined by a complex system of enzymes that had been taking form for billions of years of biological evolution. The above phenomenon became the impetus that made the author address, and develop a profound interest in, the problem of the origin of life. In 2001, a book was published titled Phenomenon of Life: Between Equilibrium and Non-Linearity (Galimov, 2001). In the book it was concluded that the ever-increasing ordering of matter that is peculiar to life is an immanent property of the steady state system of conjugated reactions, proceeding with disproportionation of entropy. The author has suggested and developed a model wherein the adenosine triphosphate (ATP) molecule plays the key role in the origin and evolution of life (Galimov, 2004a, 2006a). Development of this concept requires theoretical and experimental studies in which the author is taking part at present. Following the initiative, the Russian Academy of Sciences approved a dedicated program titled ‘Origin and Evolution of Biosphere’. To conclude, the author believes that the 21st century will be marked by two main achievements: (1) the solution of the problem of the origin of life, which will enlarge our understanding of the Universe and provide an impetus to development of new biotechnologies; and (2) economical exploration of the Moon, which will provide the most efficient and the most environmentally acceptable solution to the energy problem. The activities of the International Association of GeoChemistry can provide a valuable contribution to both these directions. References Bogacheva, M.P., Galimov, E.M., 1979. Intramolecular distribution of carbon isotopes in chlorophyll and hemine. Geokhimia (7), 1166–1172. Cameron, A.G.W., Ward, W., 1976. The origin of the Moon. In: Proc. 7th Lunar Science Conf., pp. 120–122. Canap, R.M., 2004. Simulations of a late lunar forming impact. Icarus 168, 433–456. Galimov, E.M., 1968. Geochemistry of Stable Carbon Isotopes. Nedra, Moscow. Galimov, E.M., 1971. On the relationship of the isotope fractionation coefficient to the equilibrium constants of the isotope exchange reactions of carbon in hydrocarbon systems. Russ. J. Phys. Chem. 45, 1187–1191. Galimov, E.M., 1973a. Carbon Isotopes in Oil and Gas Geology. Nedra, Moscow (NASA Translation, F-682, Washington, DC, 1975). Galimov, E.M., 1973b. Biogenetic intermolecular and intramolecular isotope effects. Method of ‘‘isotopic number of bond”. Biochemical and geochemical application. In: Internat. Meeting Isotope Effects in Physical and Chemical Processes. Cluj, Romania, pp. 96–100. Galimov, E.M., 1973c. On possibility of natural diamond syntheses under conditions of cavitation, occurring in a fast-moving magmatic melt. Nature 243, 389–391. Galimov, E.M., 1973d. Organic geochemistry of carbon isotopes. In: Tissot, B., Bienner, F. (Eds.), Advances in Organic Geochemistry. Edition Technip, pp. 439– 442. Galimov, E.M., 1974. Peculiar character of kinetic isotope effect under destruction of organic macromolecules. Russ. J. Phys. Chem. 48, 1381–1385. Galimov, E.M., 1980. 13C/12C in kerogen. In: Durand, B. (Ed.), Kerogen. Edition Technip, Paris, pp. 271–300. Galimov, E.M., 1984. The relation between formation conditions and variations in isotope composition of diamonds. Geokhimiya (8), 1091–1118 (reprinted in Geochemistry International, 1985, 118–141). Galimov, E.M., 1985. Biological Fractionation of Isotopes. Academic Press, I.N.C., Orlando, NY, London. Galimov, E.M., 1986. Isotopic method of identification of oil source rocks on case of deposits in some regions of the USSR. Izvest. Akad. Nauk SSSR, Ser. Geol. 4, 3–21.
E.M. Galimov / Applied Geochemistry 24 (2009) 1048–1051 Galimov, E.M., 1988. Sources and mechanisms of formation of gaseous hydrocarbons in sedimentary rocks. Chem. Geol. 71, 77–95. Galimov, E.M., 1991. Isotope fractionation related to kimberlite magmatism and diamond formation. Geochim. Cosmochim. Acta 55, 1697–1708. Galimov, E.M., 1995. Fractionation of carbon isotopes on the way from living to fossil organic matter. In: Wada, E., Yoneyama, T., Minagawa, M., Ando, T., Fry, D. (Eds.), Stable Isotopes in the Biosphere. Kyoto Univ. Press, Japan, pp. 133–170. Galimov, E.M., 1996. Change of the isotopic composition of organic carbon during last 10 million years, observed in sediments of the equatorial Eastern Pacific. Dok. RAN 347, 524–527. Galimov, E.M., 1999. The causes of the global variations of carbon isotopic composition in the biosphere. Geochem. Int. 37, 699–713. Galimov, E.M., 2000. Carbon isotopic composition of Antarctic plants. Geochim. Cosmochim. Acta 64, 1737–1739. Galimov, E.M., 2001, Phenomenon of life: between equilibrium and non-linearity. Origin and principles of evolution. Engl. translation: Geochem. Internat. 44 (Suppl. 1), 2006, pp. S1–S95 (in Russian). Galimov, E.M., 2004a. Phenomenon of life: between equilibrium and non-linearity. Origins Life Evol. B. 34, 599–613. Galimov, E.M., 2004b. On the origin of lunar material. Geochem. Internat. 42 (7), 595–609. Galimov, E.M., 2006a. Isotope organic geochemistry. Org. Geochem. 37, 1–63. Galimov, E.M., 2006b. Phobos-Grunt. The Russian project. Sci. Russia (1), 4–12. Galimov, E.M., 2007. On erroneous ‘‘experience” of isotope fractionation in enzymatic reaction. Russ. J. Phys. Chem. 81, 831–835. Galimov, E.M., Frik, M.G., 1985. Isotopic method of identification of oil-source rock. Geochemiya (10), 1474–1484. Galimov, E.M., Ivlev, A.A., 1973. Thermodynamic isotope effects of organic compounds. I. Carbon isotope effects in normal alkanes. Russ. J. Phys. Chem. 47, 2787–2791. Galimov, E.M., Kodina, L.A., 1982. Organic Matter and Gases in Sedimentary Succession of the World Ocean. Nauka, Moscow 228p. (in Russian). Galimov, E.M., Petersilie, I.A., 1967. On carbon isotope composition of hydrocarbon gases and CO2 occurring in alkali igneous rocks of Khibiny, Lovozero and Ilimaussaq intrusions. Dokl. Akad. Nauk. USSR 176, 914–917. Galimov, E.M., Polyakov, V.B., 1991. Thermodynamically ordered distribution of carbon isotopes in biogenic geochemical specimens. Geochem. Internat. 28 (4), 13–20.
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Galimov, E.M., Shabaeva, I.Yu., 1985a. Carbon isotope composition of CH4 and CO2 in sediments of the Middle American Trench. In: Initial Reports of the DSDP, Washington, US Government Printing Office, LXXXIV, pp. 693–694. Galimov, E.M., Shabaeva, I.Yu., 1985b. Carbon isotope composition of CH4 and CO2 in sediments of the Middle American Trench. Geokhimiya (6), 850–857 (DSDP Leg 84). Galimov, E.M., Shirinsky, V.G., 1975. Ordered distribution of carbon isotopes in compounds and components of the lipid fraction in organisms. Geokhimiya (4), 503–528. Galimov, E.M., Kodina, L.G., Shirinskiy, V.G., Drozdova, T.V., Generalova, V.N., Bogacheva, M.P., Chinyonov, V.A., 1980. A study of organic matter from deep oceanic bore holes Deep Sea Drilling Project, sites 415 and 416 in the Moroccan Basin. Initial Reports of the DSDP Leg 50, Washington, US Government Printing Office, pp. 575–600. Galimov, E.M., Krivtsov, A.M., Zabrodin, A.V., Legkostupov, M.S., Eneev, T.M., Sidorov, Yu.I., 2005. Dynamic model for the formation of the Earth–Moon System. Geochem. Internat. 43, 1045–1055. Galimov, E.M., Kudin, A.M., Skorobogatskiy, V.N., Plotnichenko, V.G., Bondarev, O.L., Zarubin, B.G., Strazdovskiy, V.V., Aronin, A.S., Fisenco, A.V., Bykov, I.V., Barinov, A.Y., 2004. Experimental corroboration of the synthesis of diamond in the cavitation process. Dok. RAN 395, 187–191. Galimov, E.M., Kulikov, S.D., Kremnev, R.S., Serco, Yu.A., Khavroshkin, O.B., 1999. The Russian Lunar Exploration Project. Solar System Res. 33, 327–337. Galimov, E.M., Laverov, N.P., Stepanets, O.V., Kodina, L.A., 1996. Preliminary results of ecological and geochemical investigations of the Russian Arctic Seas (data obtained from cruise 22 of the R/V ‘‘Akademik Boris Petrov”). Geochem. Internat. 34 (7), 521–538. Galimov, E.M., Teplinskiy, G.I., Tabassaranskiy, Z.A., Gavrilov, Ye.Ya., 1973. On the conditions of formation of gas deposits in the eastern part of Turan Plate as revealed by carbon isotopic composition of the gases. Geochem. Internat. 10, 1259–1271. Hartmann, W.K., Davis, D.R., 1975. Satellite-sized planets and lunar origin. Icarus 24, 504–515. Meinschein, W.G., Hageman, C.D., Bromley, B.W., 1984. Intramolecular distribution of stable isotopes of carbon. In: 27th Internat. Geol. Congress 5 (sec. 10–11), pp. 345–346. Schmidt, H.-L., 2003. Fundamentals and systematic of the nonstatistical distributions of isotopes in natural compounds. Naturwissenschaften 90, 552–597.
Contents lists available at ScienceDirect
Applied Geochemistry journal homepage: www.elsevier.com/locate/apgeochem
Advances in geochemistry during the last four decades: A personal perspective Eric M. Galimov V.I. Vernadsky Institute of Geochemistry and Analytical Chemistry, Moscow, Russia
a r t i c l e
i n f o
Article history: Available online 10 March 2009
a b s t r a c t This is the author’s speech at the meeting in Cologne (2007) to celebrate the 40th anniversary of the International Association of Geochemistry and Cosmochemistry, which the author served as the President in 2000 to 2004. The paper narrates the author’s personal involvement in important scientific programs during the last 4 decades, including implementation of isotope techniques, oil-and-gas research, diamond research, deep-sea drilling, space research, molecular biology and the origin of life. Ó 2009 Elsevier Ltd. All rights reserved.
1. Influence of isotopic methods on the development of geological sciences in the 20th century In 1966, Academician A.P. Vinogradov, the author’s teacher, who was at the time Director of the V.I. Vernadsky Institute of Geochemistry and Analytical Chemistry, organized the USSR’s first Symposium on Stable Isotopes. The author was tasked to present a plenary paper on C isotopes. Carbon is an element that forms the basis of life and is contained in some of the Earth’s most important mineral products such as oil, natural gas, coal and diamonds. Some data presented in that paper are worth mentioning here. The value of the average isotope composition of Earth’s crustal C was calculated by the author to be d13C = 5‰; this figure has been accepted as valid up to the present day. Also, the hypothesis was made that ocean water and organic C were produced due to fallout of materials similar to carbonaceous chondrites on the Earth at a later stage of its accumulation. This idea became popular in the published literature years later. In 1967, the author wrote a book titled Geochemistry of Stable Carbon Isotopes that summarized the initial stage of research in this field (Galimov, 1968). In the decades 1960 and 1970 extensive studies of oil and gas in the USSR were carried out using isotopic techniques. It was realized very soon that data interpretation was impeded by inadequate background on the isotope chemistry of organic compounds. Indeed, geochemistry of isotopes can only become a serious science when it is based on a system of thermodynamic and kinetic constants. Otherwise, it is simply a primitive empiricism. Early in the 1960s, theoretical coefficients of isotope separation (b-factors, as they were called) were only known for simple C compounds, such as CH4, CO and CO2, and for single-C crystals (diamond and graphite). As oil and gas were being dealt with at that time there was interested in calculating the isotopic constants for hydrocarbon systems. The b-factors for hydrocarbons were calculated in the author’s laboratory: alkanes up to pentane, cyclohexane, benzene, toluene, and then for acetate aldehyde, acetic acid, methylE-mail address: [email protected] 0883-2927/$ - see front matter Ó 2009 Elsevier Ltd. All rights reserved. doi:10.1016/j.apgeochem.2009.02.020
amine and some other organic compounds (Galimov and Ivlev, 1973; Galimov, 1973a). In so doing, the isotopic thermodynamics of complex organic compounds was developed, taking account of the non-equivalent position of different C atoms in organic molecules. The notion of an intramolecular isotope effect was introduced (Galimov, 1971). The author suggested a method, which became known as the ‘method of the isotopic bond numbers’, that facilitated a close approximation to the b-factor of highly complex C compounds (Galimov, 1973b, 1985). From theory, it was determined that the isotope effect depends on the band of activation energy, e.g., it is different for CH4 formed from kerogen and from a single component (Galimov, 1974). This work later proved to be important for the understanding of mechanisms of natural gas formation (Galimov, 1988). 2. Industrial development and the growth of production and use of hydrocarbon raw materials and fuels It is quite understandable that oil and gas geology became at the time a most important area of application for new isotopic methods. Several results related to the activities in that field will now be cited: (1) The author’s group suggested the oil–oil correlation and oil-source rock identification methods based on comparison of isotope compositions of the corresponding fractions extracted from oil and the organic matter of the putative oil-source beds (Galimov and Frik, 1985; Galimov, 1986). Identification of oilsource beds significantly increases the reliability of predicting the hydrocarbon reserves in sedimentary basins. The method was successfully applied in many oil fields of the former USSR. (2) It was shown that isotopic composition of CH4 depends on maturity of the gas source organic matter (Galimov, 1973a; Galimov et al., 1973). This dependence has served as an effective tool in the search for gas source rocks both in Russia and abroad. (3) It was demonstrated that the main bulk of hydrocarbons and biological markers contained in oil have a common line of isotope fractionation, which unequivocally indicates the organic origin of oil (Bogacheva and Galimov, 1979; Galimov, 1985). (4) Analysis of hydrocarbons
E.M. Galimov / Applied Geochemistry 24 (2009) 1048–1051
contained in minerals of igneous rocks showed that they have isotopic characteristics that are fundamentally different from those of hydrocarbons in sedimentary rocks (Galimov and Petersilie, 1967). (5) A vast number of oils, individual hydrocarbons, and oil fractions from many fields in the Volga-Ural region, western and eastern Siberia, Caucasus, Central Asia, and the Far East were analyzed. At the time, it was probably the most comprehensive collection of data on the isotopic composition of C in oil and gas that existed anywhere in the world. These data were summarized in a monograph Carbon Isotopes in Oil and Gas Geology (Galimov, 1973a). By the end of the 1980s, a general model of isotope fractionation in hydrocarbon gas was developed that took into account the differences between distribution functions of activation energies for organic matter of different types and structures (i.e., sapropelic and humic). This model was based on the theoretical work already mentioned on the dependence of isotopic composition on the activation energy band. It allowed interpretation of the origin of the giant gas accumulations in Cenomanian deposits of western Siberia that amount to 30% of the world’s gas resources. In general, the possibility of CH4 generation at an earlier stage of transformation of humic organic matter that was demonstrated did much to establish search criteria and prospects for evaluation of new gas-bearing territories (Galimov, 1988). The methods that are useful for oil and gas exploration have been developed on the basis of the systematic study of isotope fractionation processes on the way from living to fossil forms of organic substances (Galimov, 1980, 1995, 2006a). 3. Diamonds and economic development in the latter half of the 20th century The author was once amazed to read in a book a phrase stating that the economic potential of the USA would fall by about 1/3 if all diamonds were to be extracted from all tools in operation. In the USSR, diamond-related research activities were stimulated by the discovery of diamond-rich kimberlitic pipes in eastern Siberia. Isotopic analysis of C is a direct and profound method to investigate the nature of diamonds. Thousands of diamond crystals were analyzed in the author’s laboratory. The bulk of data produced by the end of the 1970s constituted some 90% of all isotopic data obtained for diamonds by laboratories around the world. The result of this work was to establish the fundamental laws of the distribution of C isotopes in diamond crystals with respect to deposit type, mineral paragenesis, crystal morphology, etc. (Galimov, 1984, 1991). Most remarkable was the discovery of the isotopically-light diamonds. It was totally unexpected to find such a wide range of Cisotope variation for such a high-temperature mineral. Also, an important observation was the principal difference in composition of diamonds of ultrabasic and eclogitic genesis, found in all diamond deposits. In 1973, a theoretical paper was published on possible diamond formation during the process of cavitation in an ascending kimberlite melt (Galimov, 1973c). Cavitation results from the collapse of gas bubbles as a liquid moves along a channel of variable cross-section. Cavitational formation of diamonds in kimberlitic liquid as it bursts out from the mantle offered an explanation for many diamond properties. Recently, the author’s group managed to produce diamonds by inducing cavitation in a laboratory experiment (Galimov et al., 2004). 4. Revolutionary changes in geological sciences due to research on the deep ocean floor The initiation of the ocean deep-sea drilling project (DSDP and, afterwards, ODP) opened a new window to the geology beneath the sea. Up to the early 1960s, hundreds of thousands of wells
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had been drilled in the continents, and none in the ocean. In 1976, the author participated in an expedition of the Glomar Challenger drill-ship, the flagship of ocean floor research. During Leg 50, as well No. 415 was being drilled, the re-entry procedure (repeated entering of a hole drilled in ocean floor) was attempted for the first time. Before that, drilling in bottom sediments would continue only until the drill bit wore out, which normally happened at a depth of 300–400 m. In order to replace the bit with a new one, the pipe string with the bit attached end had to be withdrawn, afterwards to be sunk again through many meters of water, exactly hitting a 10–15 cm diameter spot on the ocean floor. It was in 1976 that this procedure was successfully carried out up to 12 times using specially-designed devices. As a result, the deepest bore hole of the DSDP project (1700 m deep) was drilled. Analysis of the extracted core was undertaken initially by the organic geochemistry group aboard the vessel and then continued in detail in the author’s laboratory in the Vernadsky Institute. It was from this work that the evolution of chemical and isotopic composition of organic materials and gases along the entire depth range of sedimentary strata of the ocean was established (Galimov et al., 1980). Later on, the author took part in many nautical expeditions. One of the most fruitful cruises was the 14th run of the R/V Academician Boris Petrov carried out in 1990, which studied the H2S generating basins in the Atlantic Ocean (Cariaco), in the Mediterranean (Bannok), and in the Black Sea. In 1992, the author had occasion to work aboard the JOIDES Resolution, a more powerful American drill-ship that replaced the Glomar Challenger. The cruise traversed from north to south across the sedimentary layer of the equatorial zone of the Pacific. As a result, material was obtained that became the basis of a paper on global changes in isotopic composition of C related to climatic changes during the Cenozoic (Galimov, 1996, 1999). Detailed investigations in biogeochemistry, radiochemistry, and organic chemistry of marine sediments were also carried out in the ship, the Academician Boris Petrov, in the Arctic basin (Kara Sea) (Galimov et al., 1996). During the 1999 Antarctic passage of the Academician Boris Petrov, the author landed on islands in sub-Antarctic archipelagoes to gather mosses and lichens; later, a paper was published on the peculiar features of C composition in sub-Antarctic plants (Galimov, 2000). The last cruise that the author took part in was during November 2006, and was aimed at the search for gas hydrates in the Indian Ocean. The author has always been interested in the problem of gas hydrates, and several publications address this topic (Galimov and Shabaeva, 1985a,b; Galimov and Kodina, 1982; Galimov, 2006a). One of the conclusions, drawn as early as the beginning of the 1980s, is that gas hydrate accumulations in the ocean can only be relevant when they are related to gas inflow from deeper (more than 2–3 km deep) sea floor sediments, i.e., only in regions where such sediments and structures exist. Ocean research was one of the most fascinating enterprises in geology and geochemistry during the latter half of the 20th century. The author is happy that he could be directly involved in it. 5. Breakthroughs in our scientific knowledge resulting from studies of the Moon and planets The author had the chance to witness the epoch of Sturm und Drang in this field that took place during the 1960s and 1970s. The Vernadsky Institute, where the author worked, was at the centre of this research. The author’s group analyzed the C-isotopic composition in lunar soil returned by the Soviet Luna-16 automated probe in 1972. One should note, however, that by this time, analyses had previously been made on the lunar samples returned by the Apollo 11 to Apollo14 missions.
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The author has always been interested in the problem of the origin of the Moon. The hypothesis of Moon formation as a result of collision of the Earth with another planetary body, as put forward by Hartmann and Davis (1975) and Cameron and Ward (1976), was never satisfying. In this case, 80% of the Moon would have had to have been formed out of a foreign planetary body of unknown origin, rather than from Earth material (Canap, 2004). This did not agree with the absolute coincidence of fractionation lines of isotopic composition of the Earth and the Moon at the 3-isotope-oxygen diagram, which suggested a complete unity of the initial reservoir of the Earth and the Moon. There were other objections as well. That is why my research group began to develop an alternative chemical and dynamic model for Moon formation. It was demonstrated that the Moon and the Earth could be formed out of a common reservoir, a dust cloud that was produced within the circumsolar nebula at the earliest stage of formation of the Solar System (Galimov et al., 2005). The main idea of the hypothesis was that the dust particles were heated and partly evaporated during cloud contraction. Evaporation ensured the appearance of a repulsion force that could easily account for the advent of fragmentation at the angular momentum of the dust cloud, smaller than the momentum of the present Earth–Moon system. A model involving evaporation within the cloud could also explain the loss of volatiles without isotope fractionation, which the giant-impact model failed to explain. Finally, as it turned out, evaporation could also explain the loss of Fe and, consequently, the observed deficit of Fe in the Moon (Galimov, 2004b). Computer simulation demonstrated that, at the suggested conditions, fragmentation of a dust cloud does develop, and two condensations are formed that can be considered embryos of the Earth and the Moon. When addressing the problem of the origin of the Moon, it is important to have information on its inner structure, the size of the core, and the chemical composition of the mantle. In 1995, the author put forward a project of a space mission to the Moon aimed at investigating its inner structure. The project passed the preliminary development stage and became known under the name of Luna-Glob (Galimov et al., 1999) Launch of the spacecraft is now included in the Russian Federal Program and is scheduled for 2012. It includes special seismic experiments, to be carried out with penetrators. It is hoped that carrying out the project will allow the solution of the problem of the origin of the Moon, which is also important for reconstruction of early Earth history. The Russian Federal Program also includes another planetary research project named Phobos-Grunt (Galimov, 2006b). The Phobos-Grunt mission involves recovering samples from Phobos (a satellite of Mars). Launch of the spacecraft is scheduled for 2009. Fragments of material from Mars, known as SNC meteorites, are present on Earth. Comparing their composition with that of the samples brought back from Phobos will allow the question to be answered as to whether Phobos is related to the Martian reservoir or is an alien body captured by Mars.
6. Isotopes, molecular biology, and the origin of life One of the most paradoxical phenomena that the author has managed to discover is a specific feature of isotope fractionation in biological objects (Galimov, 1973d, 1985; Galimov and Shirinsky, 1975; Bogacheva and Galimov, 1979; Meinschein et al., 1984; Schmidt, 2003). The method of ‘isotopic bond numbers’, developed to calculate b-factors of biochemical components: lipids, proteins, and carbohydrates, was used. Measured isotopic composition of biological compounds was found to correlate to calculated values of their respective b-factors. It should be emphasized that this correlation is characteristic of biological compounds and is not to be found in analogous compound of non-biological
nature. The paradoxicality of this observation lies in the fact that the b-factor characterizes the equilibrium state. Correlation between measured isotopic compositions and b-factors is only observed in systems that are close to equilibrium. How then can one make this agree with the seemingly absolute non-equilibrium character of living systems? It has been demonstrated that such extraordinary distribution of isotopes is caused by the fact that all biosynthesis reactions in an organism are carried out and controlled by enzymes (Galimov, 1985, 2007; Galimov and Polyakov, 1991). It involves a reversible substrate-to-product transformation that takes place in the enzyme–substrate complex. Individual biochemical reactions are close to equilibrium, and the observed chemical non-equilibrium of biosystems is determined by a complex system of enzymes that had been taking form for billions of years of biological evolution. The above phenomenon became the impetus that made the author address, and develop a profound interest in, the problem of the origin of life. In 2001, a book was published titled Phenomenon of Life: Between Equilibrium and Non-Linearity (Galimov, 2001). In the book it was concluded that the ever-increasing ordering of matter that is peculiar to life is an immanent property of the steady state system of conjugated reactions, proceeding with disproportionation of entropy. The author has suggested and developed a model wherein the adenosine triphosphate (ATP) molecule plays the key role in the origin and evolution of life (Galimov, 2004a, 2006a). Development of this concept requires theoretical and experimental studies in which the author is taking part at present. Following the initiative, the Russian Academy of Sciences approved a dedicated program titled ‘Origin and Evolution of Biosphere’. To conclude, the author believes that the 21st century will be marked by two main achievements: (1) the solution of the problem of the origin of life, which will enlarge our understanding of the Universe and provide an impetus to development of new biotechnologies; and (2) economical exploration of the Moon, which will provide the most efficient and the most environmentally acceptable solution to the energy problem. The activities of the International Association of GeoChemistry can provide a valuable contribution to both these directions. References Bogacheva, M.P., Galimov, E.M., 1979. Intramolecular distribution of carbon isotopes in chlorophyll and hemine. Geokhimia (7), 1166–1172. Cameron, A.G.W., Ward, W., 1976. The origin of the Moon. In: Proc. 7th Lunar Science Conf., pp. 120–122. Canap, R.M., 2004. Simulations of a late lunar forming impact. Icarus 168, 433–456. Galimov, E.M., 1968. Geochemistry of Stable Carbon Isotopes. Nedra, Moscow. Galimov, E.M., 1971. On the relationship of the isotope fractionation coefficient to the equilibrium constants of the isotope exchange reactions of carbon in hydrocarbon systems. Russ. J. Phys. Chem. 45, 1187–1191. Galimov, E.M., 1973a. Carbon Isotopes in Oil and Gas Geology. Nedra, Moscow (NASA Translation, F-682, Washington, DC, 1975). Galimov, E.M., 1973b. Biogenetic intermolecular and intramolecular isotope effects. Method of ‘‘isotopic number of bond”. Biochemical and geochemical application. In: Internat. Meeting Isotope Effects in Physical and Chemical Processes. Cluj, Romania, pp. 96–100. Galimov, E.M., 1973c. On possibility of natural diamond syntheses under conditions of cavitation, occurring in a fast-moving magmatic melt. Nature 243, 389–391. Galimov, E.M., 1973d. Organic geochemistry of carbon isotopes. In: Tissot, B., Bienner, F. (Eds.), Advances in Organic Geochemistry. Edition Technip, pp. 439– 442. Galimov, E.M., 1974. Peculiar character of kinetic isotope effect under destruction of organic macromolecules. Russ. J. Phys. Chem. 48, 1381–1385. Galimov, E.M., 1980. 13C/12C in kerogen. In: Durand, B. (Ed.), Kerogen. Edition Technip, Paris, pp. 271–300. Galimov, E.M., 1984. The relation between formation conditions and variations in isotope composition of diamonds. Geokhimiya (8), 1091–1118 (reprinted in Geochemistry International, 1985, 118–141). Galimov, E.M., 1985. Biological Fractionation of Isotopes. Academic Press, I.N.C., Orlando, NY, London. Galimov, E.M., 1986. Isotopic method of identification of oil source rocks on case of deposits in some regions of the USSR. Izvest. Akad. Nauk SSSR, Ser. Geol. 4, 3–21.
E.M. Galimov / Applied Geochemistry 24 (2009) 1048–1051 Galimov, E.M., 1988. Sources and mechanisms of formation of gaseous hydrocarbons in sedimentary rocks. Chem. Geol. 71, 77–95. Galimov, E.M., 1991. Isotope fractionation related to kimberlite magmatism and diamond formation. Geochim. Cosmochim. Acta 55, 1697–1708. Galimov, E.M., 1995. Fractionation of carbon isotopes on the way from living to fossil organic matter. In: Wada, E., Yoneyama, T., Minagawa, M., Ando, T., Fry, D. (Eds.), Stable Isotopes in the Biosphere. Kyoto Univ. Press, Japan, pp. 133–170. Galimov, E.M., 1996. Change of the isotopic composition of organic carbon during last 10 million years, observed in sediments of the equatorial Eastern Pacific. Dok. RAN 347, 524–527. Galimov, E.M., 1999. The causes of the global variations of carbon isotopic composition in the biosphere. Geochem. Int. 37, 699–713. Galimov, E.M., 2000. Carbon isotopic composition of Antarctic plants. Geochim. Cosmochim. Acta 64, 1737–1739. Galimov, E.M., 2001, Phenomenon of life: between equilibrium and non-linearity. Origin and principles of evolution. Engl. translation: Geochem. Internat. 44 (Suppl. 1), 2006, pp. S1–S95 (in Russian). Galimov, E.M., 2004a. Phenomenon of life: between equilibrium and non-linearity. Origins Life Evol. B. 34, 599–613. Galimov, E.M., 2004b. On the origin of lunar material. Geochem. Internat. 42 (7), 595–609. Galimov, E.M., 2006a. Isotope organic geochemistry. Org. Geochem. 37, 1–63. Galimov, E.M., 2006b. Phobos-Grunt. The Russian project. Sci. Russia (1), 4–12. Galimov, E.M., 2007. On erroneous ‘‘experience” of isotope fractionation in enzymatic reaction. Russ. J. Phys. Chem. 81, 831–835. Galimov, E.M., Frik, M.G., 1985. Isotopic method of identification of oil-source rock. Geochemiya (10), 1474–1484. Galimov, E.M., Ivlev, A.A., 1973. Thermodynamic isotope effects of organic compounds. I. Carbon isotope effects in normal alkanes. Russ. J. Phys. Chem. 47, 2787–2791. Galimov, E.M., Kodina, L.A., 1982. Organic Matter and Gases in Sedimentary Succession of the World Ocean. Nauka, Moscow 228p. (in Russian). Galimov, E.M., Petersilie, I.A., 1967. On carbon isotope composition of hydrocarbon gases and CO2 occurring in alkali igneous rocks of Khibiny, Lovozero and Ilimaussaq intrusions. Dokl. Akad. Nauk. USSR 176, 914–917. Galimov, E.M., Polyakov, V.B., 1991. Thermodynamically ordered distribution of carbon isotopes in biogenic geochemical specimens. Geochem. Internat. 28 (4), 13–20.
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Galimov, E.M., Shabaeva, I.Yu., 1985a. Carbon isotope composition of CH4 and CO2 in sediments of the Middle American Trench. In: Initial Reports of the DSDP, Washington, US Government Printing Office, LXXXIV, pp. 693–694. Galimov, E.M., Shabaeva, I.Yu., 1985b. Carbon isotope composition of CH4 and CO2 in sediments of the Middle American Trench. Geokhimiya (6), 850–857 (DSDP Leg 84). Galimov, E.M., Shirinsky, V.G., 1975. Ordered distribution of carbon isotopes in compounds and components of the lipid fraction in organisms. Geokhimiya (4), 503–528. Galimov, E.M., Kodina, L.G., Shirinskiy, V.G., Drozdova, T.V., Generalova, V.N., Bogacheva, M.P., Chinyonov, V.A., 1980. A study of organic matter from deep oceanic bore holes Deep Sea Drilling Project, sites 415 and 416 in the Moroccan Basin. Initial Reports of the DSDP Leg 50, Washington, US Government Printing Office, pp. 575–600. Galimov, E.M., Krivtsov, A.M., Zabrodin, A.V., Legkostupov, M.S., Eneev, T.M., Sidorov, Yu.I., 2005. Dynamic model for the formation of the Earth–Moon System. Geochem. Internat. 43, 1045–1055. Galimov, E.M., Kudin, A.M., Skorobogatskiy, V.N., Plotnichenko, V.G., Bondarev, O.L., Zarubin, B.G., Strazdovskiy, V.V., Aronin, A.S., Fisenco, A.V., Bykov, I.V., Barinov, A.Y., 2004. Experimental corroboration of the synthesis of diamond in the cavitation process. Dok. RAN 395, 187–191. Galimov, E.M., Kulikov, S.D., Kremnev, R.S., Serco, Yu.A., Khavroshkin, O.B., 1999. The Russian Lunar Exploration Project. Solar System Res. 33, 327–337. Galimov, E.M., Laverov, N.P., Stepanets, O.V., Kodina, L.A., 1996. Preliminary results of ecological and geochemical investigations of the Russian Arctic Seas (data obtained from cruise 22 of the R/V ‘‘Akademik Boris Petrov”). Geochem. Internat. 34 (7), 521–538. Galimov, E.M., Teplinskiy, G.I., Tabassaranskiy, Z.A., Gavrilov, Ye.Ya., 1973. On the conditions of formation of gas deposits in the eastern part of Turan Plate as revealed by carbon isotopic composition of the gases. Geochem. Internat. 10, 1259–1271. Hartmann, W.K., Davis, D.R., 1975. Satellite-sized planets and lunar origin. Icarus 24, 504–515. Meinschein, W.G., Hageman, C.D., Bromley, B.W., 1984. Intramolecular distribution of stable isotopes of carbon. In: 27th Internat. Geol. Congress 5 (sec. 10–11), pp. 345–346. Schmidt, H.-L., 2003. Fundamentals and systematic of the nonstatistical distributions of isotopes in natural compounds. Naturwissenschaften 90, 552–597.