Abstract
Metabasic rocks related to pre-Cambrian protoliths from the lower portion of the deep crust of the Serre (Calabria, southern Italy) contain porphyroblastic garnet up to 5–6 cm in diameter. Garnet forms coronas around the inclusions of clinopyroxene and is in contact with various matrix minerals. Both inner and outer coronas formed under granulite facies conditions after the thermal peak during the Hercynian reworking. Six porphyroblastic garnets (≥1 cm in diameter) from four samples have been dated with the Sm-Nd method to constrain the distinct metamorphic stages and, possibly, to investigate the diffusion of Sm and Nd in garnet. They show in the core major element flat profiles whereas one of these, analyzed for REEs, preserves only a feeble zoning. This suggests that the diffusion rates of REEs are effective at the crystal scale. The apparent Nd ages range from 354 to 88 Ma, without any reproducibility in each and in all rock samples. The oldest age of 354 Ma is interpreted as the primary isotopic signatures linked to prograde metamorphism. The interpretation of younger ages (309, 272, 215, 143 and 88 Ma) requires a detailed discussion about: (i) possible modification of chemical and isotopic composition of the rocks during and after garnet growth, (ii) possible contamination by inclusions in garnet, (iii) inherited isotopic disequilibrium, (iv) new growth or recrystallization of garnet and (v) possible isotopic resetting of large crystals which, in principle, is hampered by the slow diffusion of REE’s in garnet. Some of the Nd ages are similar to U-Pb ages of zircon from the metabasic rocks of deep crustal rocks of the Serre (350, 300 and 280 Ma). This convergence of apparent ages can hardly be considered as simply fortuitous. Thus, since: (i) corona formation was fluid-assisted and (ii) all porphyroblasts were broken up into several fragmented subgrains by sets of fractures resulting in smaller volumes, the volume diffusion and the possible role of high-T fluids on the resetting of Sm-Nd ages are discussed. The calculated ages of 354, 309 and 272 Ma are considered as geologically meaningful and related to the thermal peak and subsequent decompression and cooling stage of the Variscan metamorphism.
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Acquafredda P, Fornelli A, Paglionico A, Piccarreta G (2006) Petrological evidence for crustal thickening and extension in the Serre granulite terrane (Calabria, southern Italy). Geol Mag 143:1–19
Acquafredda P, Fornelli A, Piccarreta G, Pascazio A (2008) Multi-stage dehydration-decompression in the metagabbros from the lower crustal rocks of the Serre (southern Calabria, Italy). Geol Mag 145–3:397–411
Caggianelli A, Del Moro A, Paglionico A, Piccarreta G, Pinarelli L, Rottura A (1991) Lower crustal genesis connected with chemical fractionation in the continental crust of Calabria (Southern Italy). Europ J Mineral 3:159–180
Caggianelli A, Prosser G, Del Moro A (2000) Cooling and exhumation history of deep-seated and shallow level, late Hercynian granitoids from Calabria. Geol J 35:33–42
Caggianelli A, Prosser G (2002) Modelling the thermal perturbation of the continental crust after intraplating of thick granitoid sheets: A comparison with the crustal sections in Calabria (Italy). Geol Mag 139:699–706
Carignan J, Hild P, Mévelle G, Morel J, Yeghicheyan D (2001) Routine analyses of trace elements in geological samples using flow injection and low pressure on-line liquid chromatography coupled to ICP-MS: A study of referente materials BR, DR-N, UB-N, AN-G and GH. Geostand Newsl 25:187–198
Dodson MH (1973) Closure temperature in cooling geochronological and petrological system. Contr Mineral Petrol 40:259–274
Dutch R, Hand M (2010) Retention of Sm-Nd isotopic ages in garnets subjected to high-grade thermal reworking: Implications for diffusion rates of major and rare earth elements and the Sm-Nd closure temperature in garnet. Contrib Mineral Petrol 159:93–112
Festa V, Fornelli A, Paglionico A, Pascazio A, Piccarreta G, Spiess R (2012) Asynchronous extension of the late-Hercynian crust in Calabria. Tectonophysics 518–521:29–43
Fornelli A, Piccarreta G, Del Moro A, Acquafredda P (2002) Multistage-melting in the lower crust of the Serre (southern Italy). J Petrol 43:2191–2217
Fornelli A, Piccarreta G, Acquafredda P, Micheletti PA (2004) Geochemical fractionation in migmatitic rocks from Serre granulitic terrane (Calabria, southern Italy). Periodico di Mineralogia LXXIII 2:145–157
Fornelli A, Langone A, Micheletti F, Piccarreta G (2011a) Time and duration of Variscan high-temperature metamorphic processes in the south European Variscides: Constraints from U-Pb chronology and trace element chemistry of zircon. Miner Petrol. doi:10.1007/s00710-011-0156-8
Fornelli A, Pascazio A, Piccarreta G (2011b) Diachronic and different metamorphic evolution in the fossil Variscan lower crust of Calabria. Int J Earth Sci (Geol Rundsch). doi:10.1007/s00531-011-0721-8
Frei R, Rosing MT, Waight TE, Ulfbeck DG (2002) Hydrothermal-metasomatic and tectono-metamorphic processes in the Isua supracrustal belt (West Greenland): A multi-isotopic investigation of their effects on the earth’s oldest oceanic crustal sequence. Geochim Cosmochim Acta 66:467–486
Ganguly J, Tirone M, Hervig RL (1998) Diffusion kinetics of Samarium and Neodymium in garnet, and a method for determining cooling rates of rocks. Science 281:805–807
Ganguly J, Tirone M (1999) Diffusion closure temperature and age of a mineral with arbitrary extend of diffusion: Theoritical formulation and applications. Earth Planet Sci Lett 170:131–140
Harley SL (1984) An experimental study of the partitioning of Fe and Mg between garnet and orthopyroxene. Contrib Mineral Petrol 86:359–373
Harvey J, Baxter EF (2009) An improved method for TIMS high precision neodymium isotope analysis of very small aliquots (1–10 ng). Chem Geol 258:251–257
Hensen B, Zhou B (1995) Retention of isotopic memory in garnets partially broken down during an overprinting granulite-facies metamorphism: Implications for the Sm-Nd closure temperature. Geol 23:225–228
Hensen BJ, Zhou B, Thost DE (1995) Are reaction textures reliable guides to metamorphic histories? Timing constraints from garnet Sm-Nd chronology for ‘decompression’ textures in granulites from Sostrene Island, Prydz Bay. Antartica Geol J 30:261–271
Hermann J, Rubatto D (2003) Relating zircon and monazite domains to garnet growth zones: Age and duration of granulite facies metamorphism in the Val Malenco lower crust. J Metam Geol 21:833–852
Jagoutz E (1988) Nd and Sm systematics in an eclogite xenolith from Tanzania: Evidence for frozen mineral equilibria in the continental lithosphere. Geochim Cosmochim Acta 52:1285–1293
John T, Sherer E, Haase K, Schenk V (2004) Trace element fractionation during fluid-induced eclogitization in a subducting slab: Trace element and Lu-Hf-Sm-Nd isotope systematics. Earth Planet Sci Lett 227:441–456
Jung S, Hellebrand E (2006) Trace element fractionation during high-grade metamorphism and melting - Constraints from garnet geochronology and ion microprobe data. Lithos 87:193–213
Jung S, Hoernes S, Mezger K (2001) Trace element and isotopic (Sr, Nd, Pb, O) arguments for a mid-crustal origin of Pan-African garnet-bearing S-type granites from the Damara orogen (Namibia). Precamb Res 110:325–355
Jung S, Mezger K (2001) Geochronology in migmatites—A Sm-Nd, U-Pb and Rb-Sr study from the Proterozoic Damara belt (Namibia) and implications for polyphase development of migmatites in high-grade terranes. J Metam Geol 19:77–79
Jung S, Mezger K (2003a) Petrology of basement-dominated terranes: I. Regional metamorphic T–t path from U–Pb monazite and Sm–Nd garnet geochronology (Central Damara orogen, Namibia). Chem Geol 198:223–247
Jung S, Mezger K (2003b) U-Pb garnet chronometry in high-grade rocks—case studies from the central Damara orogen (Namibia) and implications for the interpretation of Sm-Nd garnet ages and the role of high U-Th inclusions. Contrib Mineral Petrol 146:382–396
Luais B, Telouk P, Albarede F (1997) Precise and accurate neodymium isotopic measurements by plasma-source mass spectrometry. Geochim Cosmochim Acta 61:4847–4854
Luais B, Duchêne S, de Sigoyer JD (2001) Sm-Nd disequilibrium in high-pressure, low-temperature Himalayan and Alpine rocks. Tectonophysics 342:1–22
Luais B, Le Carlier de Veslud C, Géraud Y, Gauthier-Lafaye F (2009) Comparative behavior of Sr, Nd and Hf isotopic systems during fluid-related deformation at middle crust levels. Geochim Cosmochim Acta 73:2961–2977
Lu M, Hofmann AW, Mazzucchelli M, Rivalenti G (1997) The mafic-ultramafic complex near Finero (Ivrea-Verbano Zone), II. Geochronology and isotope geochemistry. Chem Geol 140:223–235
Ludwig KR (2003) User’s Manual for A Geochronological Toolkit for Microsoft Excel. Berkeley Geochronology Center. Spec Publ 4:25
Martin L, Duchêne S, Deloule E, Vanderhaeghe O (2006) The isotopic composition of zircon and garnet: A record of the metamorphic history of Naxos, Greece. Lithos 87:174–192
Martin C, Duchêne S, Luais B, Goncalves P, Deloule E, Fournier C (2010) Behavior of trace elements in relation to Lu–Hf and Sm–Nd geochronometers during metamorphic dehydration–hydration in the HP domain of Vårdalsneset, Western Gneiss Region. Norway Contrib Mineral Petrol 159:437–458
McDonough WF, Sun S (1995) The composition of the Earth. Chem Geol 120:223–253
Mezger K, Essene EJ, Halliday AN (1992) Closure temperature of the Sm-Nd system in metamorphic garnets. Earth Planet Sci Lett 13:397–409
Micheletti F, Barbey P, Fornelli A, Piccarreta G, Deloule E (2007) Latest Precambrian to Early Cambrian U-Pb zircon ages of augen gneisses from Calabria (Italy), with inference to the Alboran microplate in the evolution of the peri-Gondwana terranes. Int J Earth Sci 96–5:843–860
Micheletti F, Fornelli A, Piccarreta G, Barbey P, Tiepolo M (2008) The basement of Calabria (southern Italy) within the context of the Southern European Variscides: LA-ICPMS and SIMS U-Pb zircon study. Lithos 104:1–11
Mørk MBE, Mearns EW (1986) Sm-Nd isotopic systematics of a gabbro-eclogite transistion. Lithos 19:255–267
Ottamendi JE, de la Rosa JD, Patiño Douce AE, Castro A (2002) Rayleigh fractionation of heavy rare earths and yttrium during metamorphic garnet growth. Geol 30:159–162
Paglionico A, Piccarreta G (1976) Le Unità del Fiume Pomo e di Castagna nelle Serre Settentrionali (Calabria). Boll Soc Geol It 95:27–37
Paglionico A, Piccarreta G (1978) History and petrology of a fragment of the deep crust in the Serre (Calabria, Italy). Neues Jahrb Mineral Petrogr Mitt Monatsh 9:385–396
Pollington A, Baxter EF (2011) High precision microsampling and preparation of zoned garnet porphyroblasts for Sm–Nd geochronology. Chem Geol 281:270–282
Prince CI, Kosler J, Vance D, Gunther D (2000) Comparison of laser ablation ICP-MS and isotope dilution REE analyses—implications for Sm–Nd garnet geochronology. Chem Geol 168:255–274
Rizzo G, Piluso E, Morten L (2005) Tonalitic to trondhjemitic dykes within metabasic lower-crust rocks, Serre Massif, Calabrian-Peloritan Arc. Boll Soc Geol It 4:45–52
Rolland Y, Cox S, Boullier AM, Pennacchioni G, Mancktelow N (2003) Rare earth and trace element mobility in mid-crustal shear zones: Insights from the Mont Blanc Massif (Western Alps). Earth Planet Sci Letters 214:203–219
Romer RL, Rötzler J (2011) The role of element distribution for the isotopic dating of metamorphic minerals. Eur J Mineral 23(1):17–33
Rossi P, Cocheri A, Fanning CM, Deloule E (2006) Variscan to eo-Alpine events recorded in European lower-crust zircons sampled from the French Massif Central and Corsica, France. Lithos 87:235–260
Rubatto D (2002) Zircon trace element geochemistry: Partitioning with garnet and the link between U–Pb ages and metamorphism. Chem Geol 184:123–138
Schenk V (1980) U-Pb and Rb-Sr radiometric dates and their correlation with metamorphic events in the granulite-facies basement of the Serre, Southern Calabria (Italy). Contrib Mineral Petrol 73:23–38
Schenk V (1984) Petrology o felsic granulites, metapelites, metabasics, ultramafics, and metacarbonates from Southern Calabria (Italy): Prograde metamorphism, uplift and cooling of a former lower crust. J Petrol 25:255–298
Schenk V (1989) P-T-t path of the lower crust in the Hercynian fold belt of Souther Calabria. In Daly JS, Cliff RA, Yardley BWD (eds)—Evolution of metamorphic belts. Geol Soc Special Publ, 43, pp 337–342.
Senesi G (1999) Petrologia della zona di bordo delle plutoniti delle Serre (Catanzaro, Calabria). PhD Thesis, Bari University (Italy), pp. 80.
Thöni M, Jagoutz E (1992) Some new aspects in dating eclogites in orogenic belts: Sm-Nd, Rb-Sr and Pb-Pb isotopic results from the Austroalpine Saualpe and Koralpe type-locality (Carinthia/Styria, southeastern Austria). Geochim Cosmochim Acta 56:347–368
Thöni M (2003) Sm-Nd isotope systematics in garnet from different lithologies (Eastern Alps): Age results, and an evaluation of potential problems for garnet Sm-Nd chronometry. Chem Geol 194–4:353–379
Tiepolo M (2003) In situ Pb geochronology of zircon with laser ablation-inductively coupled plasma-sector field mass spectrometry. Chem Geol 199:159–177
Tiepolo M, Bottazzi P, Palenzona M, Vannucci R (2002) A laser probe coupled with ICP–double-focusing sector–field mass spectrometer for in situ analysis of geological samples and U–Pb dating of zircon. Can Mineral 41:259–272
Tirone M, Ganguly J, Dolmen R, Langenhorst F, Hervig R, Becker HW (2005) Rare earth diffusion kinetics in garnet: Experimental studies and applications. Geochim Cosmochim Acta 69–9:2385–2398
van Achterbergh E, Ryan CG, Jackson S, Griffin W (2001) Data reduction software for LA-ICPMS. In: Sylvester P (ed) Laser ablation ICPMS in the earth science. Mineral Assoc Canada 29: 239–243
Vance D, O’Nions RK (1990) Isotopic chronometry of zoned garnets: Growth kinetics and metamorphic histories. Earth Planet Sci Lett 97:227–240
Van Orman JA, Grove TL, Shimizu N (2001) Rare earth diffusion in diopside: Influence of temperature, pressure, and ionic radius, and an elastic model for diffusion in silicates. Contrib Mineral Petrol 141:687–703
Van Orman JA, Grove TL, Shimizu N, Layne GD (2002) Rare earth element diffusion in a natural pyrope single crystal at 2.8 GPa. Contrib Mineral Petrol 142:417–424
Zhou B, Hensen BJ (1995) Inherited Sm/Nd isotope components preserved in monazite inclusions within garnets in leucogneiss from East-Antartica and its implications for closure-temperature studies. Chem Geol 121:317–326
Acknowledgements
We thank two anonymous reviewers, Associate Editor J. Košler and J. G. Raith for their criticism and useful suggestions. We are grateful to A. Langone (IGG-CNR, Pavia, Italy) for the execution of REE analyses on garnet by LA-ICP-MS. This study benefited from the financial support of PRIN 2007 and Aldo Moro University, Bari (G. Piccarreta).
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Duchene, S., Fornelli, A., Micheletti, F. et al. Sm-Nd chronology of porphyroblastic garnets from granulite facies metabasic rocks in Calabria (Southern Italy): inferences for preserved isotopic memory and resetting. Miner Petrol 107, 539–551 (2013). https://doi.org/10.1007/s00710-012-0229-3
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DOI: https://doi.org/10.1007/s00710-012-0229-3