Geochemistry Dept. Home Page 
Abteilung Geochemie - Postfach 3060 - 55020 Mainz - Germany
E-mail address:
puchtel@geobar.mpch-mainz.mpg.de
TEL: +49 6131 305394 FAX: +49 6131 371051 Background
1. University education
1978 Department of Petrography, Geological Prospecting Institute (MGRI), Moscow
1983 B.Sc. (hons.), Department of Petrography MGRI.
2. Professional background
1983 Postgraduate student, Department of Petrology IGEM, Moscow
1985 Junior research scientist, Department of Petrology IGEM 1990 Research scientist, Department of Petrology IGEM 1995 Postdoctoral researcher, Max-Planck Institut für Chemie in Mainz3. Academic degrees
1992 Ph.D. in Geology and Mineralogy, IGEM, Moscow (Prof. O. Bogatikov, Prof. I. Ryabchikov, Prof. O. Rosen, Moscow). Title of the dissertation: "Petrology of mafic-ultramafic rocks and crust-mantle evolution in the early Precambrian: a case study from the Olekma gneiss-greenstone terrane, Aldan Shield".
Trace element and radiogenic isotope (Rb-Sr, Sm-Nd, U-Pb, Pb-Pb, Re-Os) geochemistry and geochronology, petrology of mafic-ultramafic rocks, origin and growth of the Earth's crust and complementary mantle evolution.
1. Evolution of the crust-mantle system
This was the major topic of my Ph'D thesis assigned as a case study from the Olekma granite-greenstone terrane, Aldan Shield. The main emphasis was placed on the petrology of mafic- ultramafic rocks. In my studies of these rocks from several greenstone belts in the Olekma region ranging in age from the early Archaean to early Proterozoic, I tried to combine thorough field and petrographic observations with processing the material using electron and ion microprobe, XRF, and ID-TIMS techniques. The information obtained was then used to reconstruct the timing and environment of rock deposition, and the conditions of magma generation, the compositions of mantle sources and their evolution in time and space. It was shown that the lowermost part of the Olekma GGT consists of the early Archaean (3.4 Ga) mafic supracrustal sequences. These form the basement for the late Archaean (3.0 Ga) granite-greenstone belts and were intruded by picrite dike swarms in the early Proterozoic (2.2 Ga). The earliest sequences are characterized by a predominance of Al-depleted komatiites, while Al-undepleted komatiites prevail in the late Archaean greenstone belts. In the Proterozoic, komatiites are replaced by picrites derived from basaltic magmas. Irreversible cooling of the Precambrian mantle resulted in a successive decrease in the depth of melting initiation and consequent changes in liquidus mineral assemblages also, hence, in the geochemistry of volcanics. The early Precambrian mantle was isotopically uniform and reveal long-term depletion in highly incompatible elements. Its evolution was controlled by three dominant processes: continuous temperature decrease, extraction of continental crustal material, and returning of oceanic crust back into the mantle.
2. The mechanisms and history of the early Precambrian continental growth and complementary mantle evolution
During my postdoctoral research at IGEM and at the Max-Planck Institut für Chemie I have been involved in work on the problems of origin and evolution of the Earth's crust. We test several tectonic models for the origin of the early Precambrian granite-greenstone belts, which are among the best preserved "witnesses" of the distant geological past. We compare the inferred tectonic settings and compositions of lavas from various greenstone belts with compositions of recent oceanic, island arc and continental magmas on the basis of field relationships and Nb-Th-U-REE and Nd-Pb isotope data. We suggest that mantle plumes were major contributors of juvenile crustal material in the Baltic shield creating oceanic and continental volcanic plateaux. Oceanic plateaux were accreted laterally to the existing continental blocks by the processes of plate tectonics and became new fragments of continental crust. The plumes that rose beneath the continental blocks, created several continental flood basalt provinces and contributed to the vertical growth of the continental crust. Furthermore, we used the Nb/U ratio, calculated from Th-U-Pb relationships in thoroughly selected uncontaminated rocks, in order to deduce the history of continental crustal growth. Our studies of several Archaean and Proterozoic volcanic provinces within the Baltic shield imply a nearly constant continental mass since the Archaean provided that the mass of the residual, and presumably convecting mantle reservoir was constant through time. We plan further detailed geochemical and isotope studies of rocks of different age and from various continents in order to test the possible universal character of the "near-steady-state no-continental-growth" model.
3. Oceanic crust recycling and core-mantle interaction in the Precambrian
This new project is aimed at studying the Pt-Re-Os isotope system in mafic-ultramafic lavas from three large provinces within the Baltic Shield in order to estimate the influence of oceanic crust recycling upon the source composition, the timing and rate of this recycling and the duration of the oceanic crust storage in the mantle as well as the extent of chemical exchange between the mantle and outer core in the generation of the plume-derived magmas.
The Earth's upper mantle is characterized by essentially chondritic Re/Os and Pt/Os ratios. Due to the fact that Os is highly compatible with the solid mantle residue whereas Re is moderately incompatible, the basaltic oceanic crust must have had high Re/Os ratios, which with time produce radiogenic Os isotope compositions. Therefore, the recycled basaltic component may be easily identified by elevated 187Os/188Os isotope ratios in plume-derived magmas. Indeed, this component has been recognized in some oceanic basalts. However, some plume-derived magmas reveal elevated both 187Os/188Os and 186Os/188Os isotope ratios. The increase in 186Os/188Os is a result of 190Pt decay. Unlike Re, Pt is moderately compatible during mantle melting and therefore mantle enrichment in 186Os cannot be accounted for by oceanic crust recycling, but is consistent with the derivation of the Os from the outer core.
Pt-Re-Os evidence for mantle evolution models and oceanic plate tectonics operating in the early Precambrian is far less straightforward and the Re-Os data on Precambrian rocks are still extremely scarce. One of the difficulties encountered is the necessity for age-correction procedures, which requires precise evaluation of Re/Os ratios in the original rock. This proved an extraordinarily difficult quest mostly owing to the Re-mobility during secondary alteration processes. Another complication is that the previous studies were performed on single spatially separated objects thus not allowing to trace the temporal evolution of the mantle. The third obstacle is crustal contamination, which results in elevated 187Os/188Os in hybrid magmas, the excess radiogenic 187Os being introduced from the continental crust.
The samples of rocks and mineral separates we select for this study cover a time span between 2.8 and 2.0 Ga. They represent plume-derived magmas and are characterized by good state of preservation of primary mineralogy. These rocks were emplaced in a variety of tectonic settings; most of them escaped crustal contamination.
Recent studies of Lu-Hf isotope geochemistry (Blichert-Toft & Albarède 1997) also suggest that a large volume of subducted basalts is presently hidden in the mantle and the source of oceanic basalts is dominated by ancient residues left after melting. We plan to test the oceanic crust recycling model by studying the Lu-Hf isotopic system in the rocks from the three provinces highlighted above in collaboration with the colleagues from Lyon.
4. Re-Os systematics of the Archaean upper mantle as inferred from studies of an ancient opiolite
The modern upper mantle sampled by MORB is characterized by essentially chondritic Re/Os ratios and Os isotope compositions. However, it is not known if these compositions reflect the long-term chondritic Re/Os ratio of the source regions, or represent mixtures of several non-chondritic reservoirs, especially taking into account the fact that the modern mantle is highly heterogeneous with respect to Os isotopes. Moreover, reliable data that demonstrate chondritic evolution of the upper mantle with time, particularly with respect to Precambrian rocks, are almost completely lacking.
Determining the Os isotope composition of the Archaean upper mantle is a difficult task. Abundant basalts derived from upper mantle sources have low Os concentrations and high Re/Os ratios. Komatiites are more suitable from a Re-Os standpoint, but they are normally considered as plume-related. One possibility is to study ancient ophiolites. They include ultramafic sections that likely represent uppermost oceanic mantle and lower oceanic crust. Such rocks typically have low Re/Os ratios and can, therefore, be used to accurately estimate initial Os isotope compositions in the Precambrian upper mantle.
Although Precambrian ophiolites are rare, there are several postulated examples such as the ~2.0 Ga old Outokumpu ophiolite in Finland. Another occurrence is the 3.0 Ga old Olondo greenstone belt in the Aldan shield, which contains sheeted dike complex, abundant gabbro intrusions, large bodies of ultramafic cumulates and tectonite peridotites. These are interpreted as representing obducted upermost section of ancient oceanic lithosphere (e.g., Dobretsov et al., 1992). We plan to study Re-Os isotope system in several lenses including the Red Hill massif consisting entirely of dunites and harzburgites (Puchtel and Zhuravlev, 1993).
Puchtel, I.S., Hofmann, A.W., Mezger, K., Jochum, K.P., Shchipansky, A.A. and Samsonov, A.V. Oceanic plateau model for continental crustal growth in the Archean: a case study from the Kostomuksha greenstone belt, NW Baltic Shield. Earth Planet. Sci. Lett., 1997 (in press).
Puchtel, I.S., Arndt, N.T., Hofmann, A.W., Haase, K.M., A. Kröner, Kulikov, V.S., Kulikova, V.V., Garbe-Schönberg, C.-D., and Nemchin, A.A. Petrology of mafic lavas within the Onega plateau, central Karelia: Evidence for the 2.0 Ga plume-related continental crustal growth in the Baltic Shield. Contrib. Mineral. Petrol., 1997 (in press).
Puchtel, I.S., Hofmann, A.W., Jochum, K.P., Mezger, K., Shchipansky, A.A., and Samsonov, A.V. The Kostomuksha greenstone belt, NW Baltic Shield: Remnant of a late Archean oceanic plateau? Terra Nova, 1997, vol. 9, pp. 87-90.
Puchtel, I.S., Haase, K.M., Hofmann, A.W., Chauvel, C., Kulikov, V.S., Garbe-Schönberg, C.-D., and Nemchin, A.A. Petrology and geochemistry of crustally contaminated komatiitic basalts from the Vetreny Belt, southeastern Baltic Shield: Evidence for an early Proterozoic mantle plume beneath rifted Archean continental lithosphere. Geochim. Cosmochim. Acta, 1997, vol. 61, pp. 1205-1222.
Puchtel, I.S., Shchipansky, A.A., Samsonov, A.V., and Zhuravlev, D.Z. The Karelian granite-greenstone terrain in Russia. In: deWit, M.J. and Ashwal, L.D. (eds), Greenstone Belts. Clarendon Press, Oxford, 1997, pp 699-706.
Puchtel, I.S., Hofmann, A.W., Mezger, K., Shchipansky, A.A., Kulikov, V.S., and Kulikova, V.V. Petrology of a 2.41 Ga remarkably fresh komatiitic basalt lava lake in Lion Hills, Central Vetreny Belt, Baltic Shield: Contrib. Mineral. Petrol., 1996, vol. 124, pp. 273-290.
Kovalenko, V.I., Yarmolyuk, V.V., Puchtel, I.S., Stosch, H.-G., Jagoutz, E., and Korikovsky, S.P. Igneous rocks and magma sources of the Ozernaya Zone ophiolites, Mongolia. Petrology, 1996, vol. 4, pp. 420-459.
Kovalenko, V.I., Puchtel, I.S., Yarmolyuk, V.V., Zhuravlev, D.Z., Stosch, H.-G., and Jagoutz, E. The Sm-Nd isotope systematics of ophiolites in the Ozernaya Zone (Mongolia). Stratigraphy and Geological Correlation, 1996, vol. 4, pp. 107-113.
Stosch, H.-G., Ionov, D.A., Puchtel, I.S., Galer, S.J.G., and Sharpouri, A. Lower crustal xenoliths from Mongolia and their bearing on the nature of the deep crust beneath central Asia. Lithos, 1995, vol. 36, pp. 227-242.
Puchtel, I.S., Bogatikov, O.A., Kulikov, V.S., Kulikova, V.V., and Zhuravlev, D.Z. The role of crustal and mantle sources in the petrogenesis of continental magmatism: Evidence from isotope and geochemical studies of the early Proterozoic picrites from the Onega plateau, Baltic Shield. Petrology, 1995, vol. 3, pp. 397-419.
Puchtel, I.S., Zhuravlev, D.Z., and Kulikova, V.V. Petrology and Sm-Nd and Pb-Pb isotope systematics of the early Archean high-magnesian metavolcanics of the Vodla Block, Baltic Shield. International Geology Review, 1993, vol. 35, pp. 825-839.
Puchtel, I.S., Bogatikov, O.A., and Simon, A.K. The early Precambrian crust-mantle evolution of the Olekma gneiss-greenstone terrane, Aldan Shield. Petrology, 1993, vol. 1, pp. 451-473.
Puchtel, I.S. and Zhuravlev, D.Z. Petrology of mafic-ultramafic metavolcanics and related rocks from the Olondo greenstone belt, Aldan Shield. Petrology, 1993, vol. 1, pp. 308-348.
Samsonov, A.V., Puchtel, I.S., Zhuravlev, D.Z., and Chernyshev, I.V. Geochronology of the Archaean Auli Gneiss Complex and the problem of the basement under the greenstone belts in the Ukrainian Shield. Petrology, 1993, vol. 1, pp. 23-41.
Puchtel, I.S. and Zhuravlev, D.Z. Nd-isotope systematics and petrogenesis of the early Proterozoic picrites in the Olekma granite-greenstone terrane. Geochemistry International, Scripta Technica, N.Y., 1993, vol. 30, No. 3, pp. 37-49.
Puchtel, I.S., Zhuravlev, D.Z., Samsonov, A.V., and Arndt, N.T. Petrology and geochemistry of metamorphosed komatiites and basalts from the Tungurcha greenstone belt, Aldan Shield. Precambrian Res., 1993, vol. 62, pp. 399-417.
Puchtel, I.S. Petrology of Mafic-Ultramafic Rocks and Evolution of the Crust-Mantle System in early Precambrian of the Olekma gneiss-greenstone terrain, Aldan Shield. Ph.D. thesis, Institute of Ore Deposit Geology, Petrology, Mineralogy and Geochemistry, Russian Academy of Sciences, Moscow, 1992, 280 p.
Puchtel, I.S., Zhuravlev, D.Z., Kulikov, V.S., and Kulikova, V.V. Petrography and Sm-Nd age of a differentiated sheet of komatiitic basalt in the Vetreny belt, Baltic Shield. Geochemistry International, Scripta Technica, N.Y., 1991, vol. 28, No. 12, pp. 14-23.
Kepezhinskas, P.K., Kepezhinskas, K.B., and Puchtel, I.S. Lower Paleozoic oceanic crust in Mongolian Caledonides: Sm-Nd isotope and trace element data. Geophys. Research Letters, 1991, vol. 18, pp. 1301-1304.
Puchtel, I.S., Frikh-Khar, D.I., Ashikhmina, N.A., Tomashpol'sky, Yu.Ya, and Shirina, N.G. Metamorphic olivines in ultramafic rocks of the Olondo greenstone belt and the komatiite identification problem. International Geology Review, Scripta Technica, N.Y., 1991, vol. 33, pp. 161-173.
Puchtel, I.S. Comparative petrology of the oldest ultramafic rocks of the Earth and Moon. In: Sharkov, E.V. (Ed.). Magmatism of the Earth and the Moon: Results of Comprehensive Studies. Nauka, Moscow, 1990, pp. 153-175.
Zhuravlev, D.Z., Puchtel, I.S., and Samsonov, A.V. Sm-Nd age and geochemistry of metavolcanics from the Olondo greenstone belt, Aldan Shield. Izv. Akad. Nauk SSSR, Ser. Geol., 1989, No. 2, pp. 32-49
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Drugova, G.M., Puchtel, I.S., Shustova, L.E., and Berezhnaya, N.G. Olondo greenstone belt, Aldan Shield. Izv. Akad. Nauk SSSR, Ser. Geol., 1988, No. 8, pp. 40-56.
Puchtel, I.S. and Simon, A.K. Precambrian ultramafic metavolcanics of greenstone belts. In: Laz'ko, E.E. and Sharkov, E.V. (Eds.) Igneous Rocks, vol. V (Ultramafic Rocks). Nauka, Moscow, 1988, pp. 230-248.
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