Pre-Variscan granitoids with adakitic signature at west Getic basement of the South Carpathians (Romania): constraints on genesis and timing based on whole-rock and zircon geochemistry


  • Anca Dobrescu Department of Regional Geology, Geological Institute of Romania. Caransebes Str. 1, 012271, Bucharest 32, Romania.



Granitoids, Adakitic signature, U-Pb zircon ages and geochemistry, Getic basement, Romanian South Carpathians


Research on two strata-like intrusions from Slatina-Timiş (STG) and Buchin (BG) at West Getic Domain of the South Carpathians (Semenic Mountains) identified granitoids with adakitic signature in a continental collision environment. Whole-rock geochemical composition with high Na2O, Al2O3 and Sr, depleted Y (<18ppm) and HREE (Yb< 1.8ppm) contents, high Sr/Y (>40), (La/Yb)N (>10) ratios and no Eu anomalies overlaps the High-Silica Adakites (HSA) main characteristics, though there are differences related to lower Mg#, heavy metal contents and slightly increased 87Sr/86Sr ratios. Comparison with HSA, Tonalite-Trondhjemite-Granodiorite (TTG) rocks and melts from experiments on basaltic sources suggests partial melting at pressures exceeding 1.25GPa and temperatures of 800-900ºC (confirmed by calculated Ti-in zircon temperatures) as the main genetic process, leaving residues of garnet amphibolite, garnet granulite or eclogite type. The adakitic signature along with geochemical variations observed in the STG-BG rocks indicate oceanic source melts affected by increasing mantle influence and decreasing crustal input that may restrict the tectonic setting to slab melting during a subduction at low angle conditions. An alternative model relates the STG-BG magma genesis to garnet-amphibolite and eclogite partial melting due to decompression and heating at crustal depth of 60-50km during syn-subduction exhumation of eclogitized slab fragments and mantle cumulates. The granitoids were entrained into a buoyant mélange during collision and placed randomly between two continental units. U-Pb zircon ages obtained by LA-ICP-MS and interpreted as Ordovician igneous crystallization time and Variscan recrystallization imprint are confirmed by trace-element characteristics of the dated zircon zones, connecting the STG-BG magmatism to a pre-Variscan subduction-collision event. The rich zircon inheritance reveals Neoproterozoic juvenile source and older crustal components represented by Neoarchean to Paleoproterozoic zircons. 


Atherton, M.P., Petford, N., 1993. Generation of sodium-rich magmas from newly underplated basaltic crust. Nature, 362,


Balica, C., 2007. Age and origin of the metamorphic units of the South Carpathians and Apuseni Mountains with possible

implications on the Pre-Alpine termotectonic evolution (in Romanian). PhD Thesis. Cluj-Napoca, University of Cluj, 212pp.

Balintoni, I., 1997. Geotectonics of Romanian Metamorphic Terrains (in Romanian). Cluj-Napoca, Editura Carpatica, 176pp.

Balintoni, I., Balica, C., Ducea, M.N., Fukun, C., Hann, H.P., Sabliovschi, V., 2009. Late Cambrian-Early Ordovician Gondwanan terranes in the Romanian Carpathians A zircon U-Pb provenance study. Gondwana Research, 16, 119-133.

Balintoni, I., Balica, C., 2010. The high U zircons, recorders of the post-crystallization thermotectonic events. Goldschmidt

Conference Abstracts, A44.

Balintoni, I., Balica, C., Ducea, M.N., Hann, H.P., Sabliovschi, V., 2010. The anatomy of a Gondwanan terrane. The Neoproterozoic-Ordovician basement of the pre-Alpine Sebeş-Lotru composite terrane (South Carpathians, Romania). Gondwana Research, 17, 561-572.

Balintoni, I., Balica, C., Ducea, M.N., Hann H.P., 2014. PeriGondwanan terranes in the Romanian Carpathians A review of the spatial distribution, origin, provenance, and evolution. Geosciences Frontiers, 5(3), 395-411.

Bayanova, T., Ludden, J., Mitrofanov, F., 2009. Timing and duration of Palaeoproterozoic events producing ore-bearing layered intrusions of the Baltic Shield: Metallogenic, petrological and geodynamic implications. Geological Society London Special Publications, 323(1), 165-198. DOI: 10.1144/SP323.8

Bea, F., Montero, P., Gonzalez-Lodeiro, F., Talavera, F., 2007. Zircon Inheritance Reveals Exceptionally Fast Crustal Magma

Generation Processes in Central Iberia during the CambroOrdovician. Journal of Petrology, 48, 2327-2339. DOI: 10.1093/petrology/egm061

Belousova, E.A., Griffin, W.L., O’Reilly, S.Y., Fisher, N.J., 2002. Igneous zircon: Trace element composition as an indicator of

source rock type. Contributions to Mineralogy and Petrology, 143, 602-622. DOI: 10.1007/s00410–002–0364–7

Castillo, P.R., 2006. An overview of adakite petrogenesis. Chinese Science Bulletin, 51, 257-268.

Castillo, P.R., 2012. Adakite Petrogenesis. Lithos, 134, 304-316.

Chamberlain, K.J., Wilson, C.J.N., Wooden, J.L., Cherlier, B.L.A., Ireland, T.R., 2014. New perspectives on the Bishop Tuff from zircon textures, ages and trace elements. Journal of Petrology, 55, 395-426. DOI: 10.1093/ petrology/egt072

Chappel, B.W., 1999. Aluminium saturation in I- and S-type granites and the characterization of fractionated haplogranites.

Lithos, 46, 535-551.

Chappell, B.W., White, A.J.R., 2001. Two contrasting granite types: 25 years later. Australian Journal of Earth Sciences, 48,


Clemens, J.D., Stevens, G., 2012. What controls chemical variations in granitic magmas? Lithos, 134-135, 317-329.

Condie, K.C., 2005. TTGs and adakites: are they both slab melts? Lithos, 80(1-4), 33-44.

Conovici, M., 2000. Geostructural study on the Getic-Supragetic domain from the south-western part of the South Carpathians (in Romanian). PhD Thesis. Cluj-Napoca, Babeş-Bolyai University, 224pp.

Defant, M.J., Drummond, M.S., 1990. Derivation of some modern arc magmas by melting of the subducted lithosphere. Nature, 347, 662-665.

Dimitrescu, R., 2007. The Neresnica-Poniasca granitoids and their prolongations within the South Carpathians. Proceedings of the Romanian Academy, 9-1, 33-35.

Dobrescu, A., Tiepolo, M., Negulescu, E., Dordea, D., 2010. U/Pb zircon geochronology on TTG rocks from South Carpathians (Romania) insights into the geologic history of the Getic crystalline basement. Greece, Proceedings of the XIX

CBGA Congress, Scientific Annals of the School of Geology Aristotle University of Thessaloniki, 99 (Special volume), 225-232.

Drummond, M.S., Defant, M.J., 1990. A model for trondhjemitetonalite-dacite genesis and crustal growth via slab melting Archaean to modern comparisons. Journal of Geophysical Research, 95, 21503-21521.

Drummond, M.S., Defant, M.J., Kepezhinskas, P.K., 1996. The petrogenesis of slab-derived trondhjemite-tonalite-dacite/adakite magmas. Transactions of the Royal Society of Edinburgh Earth Sciences, 87, 205-215.

Duchesne, J-C., Liegeois, J-P., Iancu, V., Berza, T., Matukov, D.I, Tatu, M., Sergeev, S.A., 2008. Post-collisional melting of crustal sources constraints from geochronology, petrology and Sr, Nd isotope geochemistry of the Variscan Sichevita and Poniasca granitoid plutons (South Carpathians, Romania). International Journal of Earth Sciences, 97, 705-723.

Ferry, J.M., Watson, E.B., 2007. New thermodynamic models and revised calibrations for the Ti-in-zircon and Zr-in-rutile thermometers. Contribution to Mineralogy and Petrology, 154, 429-437.

Foley, S., Tiepolo, M., Vannucci, R., 2002. Growth of early continental crust controlled by melting of amphibolite in subduction zones. Nature, 417, 637-640.

Girardi, J.D., Patchett, P.J., Ducea, M.N., Gehrels, G.E., Robinsoncecil, M., Rusmore, M.E., Woodsworth, G.J., Pearson, D.M., Manthei, C., Wetmore, P., 2012. Elemental and isotopic evidence for granitoid Genesis from deep-seated sources in the Coast Mountains Batholith, British Columbia. Journal of Petrology, 53, 1505-1536.

Gridan, T., 1981. The petrology of the north-eastern part of the Semenic Mountains (in Romanian). Bucureşti, Editura Academiei Romane, 194pp.

Grimes, C.B., John, B.E., Kelemen, P.B., Mazdab, F., Wooden, J.L., Cheadle, M.J., Hanghøj, K., Schwartz, J.J., 2007. The trace element chemistry of zircons from oceanic crust a method for distinguishing detrital zircon provenance. Geology, 35, 643-646. DOI: 101130/G23603A1

Grimes, C.B., John, B.E., Cheadle, M.J., Mazdab, F.K., Wooden, J.L., Swapp, S., Schwartz, J.J., 2009. On the occurrence, trace

element geochemistry, and crystallization history of zircon from in situ ocean lithosphere. Contribution to Mineralogy

and Petrology, 158, 757-783. DOI: 10.1007/s00410-009-0409-2

Grimes, C.B., Wooden, J.L., Cheadle, M.J., John, B.E., 2015. “Fingerptinting” tectono-magmatic provenance using trace elements in igneous zircon. Contribution to Mineralogy Petrology, 170:46, 1-26. DOI: 10. 1007/s00410-015-1199-3

Gutscher, M-A., Maury, R., Eissen, J-P., 2000. Can slab melting be caused by flat subduction? Geology, 28, 535-538.

Henderson, P., 1984. Rare Earth Element Geochemistry. Amsterdam, Elsevier, 510pp.

Hickey-Vargas, R., Moreno Roa, H., Lopez Escobar, L., Frey, F.A., 1989. Geochemical variations in Andean basaltic and silicic

lavas from the Villarica-Lanin volcanic chain (395ºS) an evaluation of source heterogeneity, fractional crystallisation and crustal assimilation. Contribution to Mineralogy and Petrology, 103, 361-386.

Hoskin, P.W.O., Black, L.P., 2000. Metamorphic zircon formation by solid-state recrystallization of protolith igneous zircon.

Journal of Metamorphic Geology, 18, 423-439.

Hoskin, P.W.O., Schaltegger, U., 2003. The Composition of Zircon and Igneous and metamorphic Petrogenesis. Reviews in

Mineralogy and Geochemistry, 53(1), 27-62.

Hu, F., Ducea, M.N., Liu, S., Chapman, J.B., 2017. Quantifying Crustal Thickness in Continental Collisional Belts: Global Perspective and a Geologic Application. Scientific Reports, 7:7058, 1-10. DOI: 10.1038/s41598-017-07849-7

Iancu, V., Mărunăiu, M., 1989. Toroniţa Zone and problems of the pre-Alpine metamorphic basement of the Getic and Danubian realms. Bucureşti, Dări de Seamă ale Institutului de Geologie şi Geofizică, 74(1), 223-237.

Iancu, V., Berza, T., Seghedi, A., Mărunţiu, M., 2005. Paleozoic rock assemblages incorporated in the South Carpathian Alpine thrust belt (Romania and Serbia) a review. Geologica Belgica, 8, 48-68.

Iancu, V., Seghedi, A., 2018. The South Carpathians: TectonoMetamorphic Units related o Variscan and Pan-African inheritance. Geo-Eco-Marina, 23, 245-262.

Martin, H., 1999. Adakitic magmas modern analogues of Archaean granitoids. Lithos, 46, 411-429.

Martin, H., Smithies, R.H., Rapp, R.P., Moyen, J-F., Champion, D.C., 2005. An overview of adakite, tonalite-trondhjemitegranodiorite (TTG) and sanukitoid relationships and some implications for crustal evolution. Lithos, 79, 1-24.

Medaris, G., Ducea, M., Ghent, E., Iancu, V., 2003. Conditions and timing of high-pressure Variscan metamorphism in the South Carpathians, Romania. Lithos, 70, 141-161.

Miller, C., McDowell, S.M., Mapes, R.W., 2003. Hot or cold granites? Implications of zircon saturation temperatures and preservation of inheritance. Geology, 31(6), 529-532. DOI: 10.1130/0091-7613(2003)031<0529:HACGIO>2.0.CO;2

Moyen, J-F., 2009. High Sr/Y and La/Yb ratios The meaning of the “adakitic signature”. Lithos, 112, 556-574.

Moyen, J-F., 2011. The composite Archean grey gneisses. Petrological significance and evidence for a non-unique tectonic setting for Archean crustal growth. Lithos, 123, 21-36.

Moyen, J-F., Martin, H., 2012. Forty years of TTG research. Lithos, 148, 312-336.

Qian, Q., Hermann, J., 2013. Partial melting of lower crust at 10-15 kbar constraints on adakite and TTG formation. Contributions to Mineralogy and Petrology, 165(6), 1195-1224.

Peacock, S.M., Rushmer, T., Thompson, A.B., 1994. Partial melting of subducting oceanic crust. Earth and Planetary Science Letters, 121, 227-244.

Pearce, J.A., Harris, N.B.W., Tindle, A.G., 1984. Trace element discrimination diagrams for the tectonic interpretation of

granitic rocks. Journal of Petrology, 25, 956-983.

Profeta, L., Ducea, M.N., Chapman, J.B., Paterson, S.R., Gonzales, S.M., Kirsh, M., Petrescu, L., DeCelles, P.G., 2015. Quantifying rustal thickness over time in magmatic arcs. Scientific Reports, 5(17786), 1-7. DOI: 10.1038/srep17786

Rapp, R.P., Watson, E.B., Miller, C.F., 1991. Partial melting of amphibolite/eclogite and the origin of Archean trondhjemites

and tonalites. Precambrian Research, 51(1-4), 1-25. DOI:

Rapp, R.P., Watson, E.B., 1995. Dehydration melting of metabasalts at 8-32 kbar implications for continental growth and crustalmantle recycling. Journal of Petrology, 36, 891-931.

Rapp, R.P., Shimizu, N., Norman, M.D., 2003. Growth of early continental crust by partial melting of eclogite. Nature, 425,


Richards, J., Kerrich, R., 2007. Special paper Adakite-like rocks their diverse origins and questionable role in metallogenesis.

Economic Geology, 102, 1-40.

Rollinson, H., Martin, H., 2005. Geodynamic controls on adakite, TTG and sanukitoid genesis implications for models of crust formation, introduction to the special issue. Lithos, 79, IX-XII.

Rubatto, D., 2002. Zircon trace element geochemistry partitioning with garnet and the link between U-Pb ages and metamorphism. Chemical Geology, 184, 123-138.

Rudnick, R.L., Gao, S., 2003. Composition of the continental crust. In: Rudnick, R.L., Holland, H.D., Turekian, K. (eds.). Treatise on geochemistry, The Crust. Elsevier, 3, 1-64.

Savu, H., 1997. On some granitods with trondhjemitic affinities from the NE Semenic Mountains - Southern Carpathians.

Analele Universităţii Bucureşti, Geologie, XLVI, 41-52.

Săbău, G., 1999. Baric types of metamorphism in the Getic Crystalline significance and implications on the interpretation

of the lithostratigraphic sequence (in Romanian). PhD Thesis. Bucharest, University of Bucharest, 270pp.

Săbău, G., Massone, H.J., 2003. Relationships among eclogite bodies and host rocks in the Lotru metamorphic suite (South Carpathians, Romania); petrological evidence for multistage tectonic emplacement of eclogites in a medium-pressure terrain. International Geology Review, 45, 225-262.

Săbău, G., Negulescu, E., 2012. U-Th-Pb Monazite Geochronology in the South Carpathian Basement Variscan Syn-Metamorphic Tectonic Stacking and Long-lasting Post-Peak Decompressional Overprints. AGU Fall Meeting, Control ID 1485915.

Săndulescu, M., Krautner, H.P., Borcoş, M., Năstăseanu, S., Patrulius, D., Ştefănescu, M., Ghenea, C., Lupu, M., Savu, H., Bercia, I., Marinescu, F., 1978. Geological map of Romania, scale 11,000,000. Geological Institute of Romania. Săndulescu, M., 1984. Geotectonics of Romania (in Romanian). București, Editura Tehnica, 336pp.

Schiller, F., Finger, F., 2019. Application of Ti-in-zircon thermometry to granite studies: Problems and possible solutions. Contribution to Mineralogy and Petrology. 174 (51), 1-16. DOI:

Smithies, R.H., 2000. The Archean tonalite-trondhjemitegranodiorite (TTG) series is not an analogue of Cenozoic adakite. Earth and Planetary Sciences Letters, 182(1), 115-125.

Stoica, A.M., Ducea, M.N., Roban, R.D., Jianu, D., 2016. Origin and evolution of the South Carpathians basement (Romania) a

ircon and monazite geochronologic study of its Alpine sedimentary cover. International Geology Review, 58(4), 510-524. DOI:

Sun, S.S., McDonough, W.F., 1989. Chemical and isotopic systematics of oceanic basalts implications or mantle composition and processes. Geological Society Special Publications, 42, 313-345.

Tiepolo, M., 2003. In situ Pb geochronology of zircon with laser ablation-inductively coupled plasma-sector field mass spectrometry. Chemical Geology, 192, 1-19.

Thirwall, M.F., Smith, T.E., Graham, A.M., Theodorou, N., Hollings, P., Davidson, J.P., Arculus, R.J., 1994. High field strength element anomalies in arc lavas source or process? Journal of Petrology, 35, 819-838.

Vavra, G., 1990. On the kinematics of zircon growth and its petrogenetic significance: a cathodoluminescence study. Contributions to Mineralogy and Petrology, 106(1), 90-99.

Wang, Q., Wyman, D.A., Xu, J.F., Jian, P., Zhao, Z.H., Li, C.H., Xu, W., 2007. Early Cretaceous adakitic granites in the Northern Dabie Complex, central China: implications for partial melting and delamination of thickened lower crust. Geochimica et Cosmochimica Acta, 71, 2609-2636.

Watson, E.B., Harrison, T.M., 1983. Zircon saturation revisited: temperature and composition effects in a variety of crustal magma types. Earth and Planetary Science Letters, 64, 295-304.

Watson, E.B., Harrison, T.M., 2005. Zircon thermometer reveals minimum melting conditions on earliest Earth. Science, 308, 841-844.

Watson, E.B., Wark, D., Thomas, J., 2006. Crystallization thermometers for zircon and rutile. Contributions to Mineralogy and Petrology, 151, 413-433.

Winther, T.K., 1996. An experimentally based model for the origin of tonalitic and trondhjemitic melts. Chemical Geology, 127, 43-59.

Whitehouse, M.J., Kamber, B., Moorbath, S., 1999. Age significance of U-Th-Pb zircon data from early Archaean rocks of west Greenland - a reassessment based on combined ion-microprobe and imaging studies. Chemical Geology, 160, 201-224.

Whitehouse, M.J., Kamber, B.S., 2005. Assigning dates to thin gneissic veins in high-grade metamorphic terranes a cautionary tale from Akilia, southwest Greenland. Journal of Petrology, 46(2), 291-318. DOI: 101093/petrology/egh075

Xiong, X.L., Liu, X.C., Zhu, Z.M., Li, Y., Xiao, W.S., Song, M.S., Zhang, S., Wu, J.H., 2011. Adakitic rocks and destruction of the North China Craton Evidence from experimental petrology and geochemistry. China Earth Sciences, 54, 858-870.

Yogodzinski, G.M., Lees, J.M., Churikova, T.G., 2001. Geochemical evidence for the melting of subducting oceanic lithosphere at plate edges. Nature, 409, 500-504.