Abstract
The Southern Alps host volcano-sedimentary basins that formed during post-Variscan extension and strike-slip in the Early Permian. We present U–Pb ages and initial Hf isotopic compositions of magmatic zircons from silicic tuffs and pyroclastic flows within these basins, from caldera fillings and from shallow intrusions from a 250 km long E–W transect (Bozen–Lugano–Lago Maggiore) and compare these with previously published data. Basin formation and magmatism are closely related to each other and occurred during a short time span between 285 and 275 Ma. The silicic magmatism is coeval with mafic intrusions of the Ivrea-Verbano Zone and within Austroalpine units. We conclude that deep magma generation, hybridisation and upper crustal emplacement occurred contemporaneously along the entire transect of the Southern Alps. The heat advection in the lower crust by injected mantle melts was sufficient to produce crustal partial melts in lower crustal levels. The resulting granitoid melts intruded into the upper crust or rose to the surface forming large caldera complexes. The compilation of Sr and Nd isotopic data of these rocks demonstrates that the mantle mixing endmember in the melts may not be geochemically enriched but has a depleted composition, comparable to the Adriatic subcontinental mantle exhumed to form the Tethyan sea floor during Mesozoic continental breakup and seafloor spreading. Magmatism and clastic sedimentation in the intracontinental basins was interrupted at 275 Ma for some 10–15 million years, forming a Middle Permian unconformity. This unconformity may have originated during large-scale strike-slip tectonics and erosion that was associated with crustal thinning, upwelling and partial melting of mantle, and advection of melts and heat into the crust. The unconformity indeed corresponds in time to the transition from a Pangea-B plate reconstruction for the Early Permian to the Late Permian Pangea-A plate assembly (Muttoni et al. in Earth Planet Sci Lett 215:379–394, 2003). The magmatic activity would therefore indicate the onset of >2,000 km of strike-slip movement along a continental-scale mega-shear, as their model suggests.
Similar content being viewed by others
References
Bachmann G, Grauert B (1981) Radiometrische Altersbestimmung des Gabbro von Sondalo, Oberes Veltlin, Italienische Alpen. Fortschr Miner Beih 59:11–12
Bakos F, Del Moro A, Visoná D (1990) The Hercynian volcano-plutonic association of Ganna (Lake Lugano, Central Southern Alps, Italy). Eur J Mineral 2:373–383
Barboza S, Bergantz G (2000) Metamorphism and anatexis in the Mafic Complex contact aureole, Ivrea Zone, Northern Italy. J Petrol 41:1307–1327
Barboza S, Bergantz G, Brown M (1999) Regional granulite facies metamorphism in the Ivrea zone: is the Mafic Complex the smoking gun or a red herring? Geology 27:447–450
Bargossi GM, Di Battistini G, Montanini A (1993a) The andesitic ignimbrites from the Lower Permian volcanic sequence in the Val di Cavè and Val di Fregio area (Trento, N Italy). Miner Petrogr Acta 36:1–17
Bargossi GM, Di Battistini G, Gasparotto G, Vercesi PL, Gualtieri S (1993b) The Permian volcano-sedimentary sequence of the Tione Basin (Val Rendena, Trento, N Italy). Miner Petrogr Acta 36:19–33
Bargossi GM, Rottura A, Vernia L, Visonà D, Tranne CA (1998) Guida all’escursione sul distretto vulcanico atesino e sulle plutoniti di Bressanone–Chiusa e Cima d’Asta. Mem Soc Geol Ital 53:23–41
Barth S, Oberli F, Meier M, Blattner P, Bargossi GM, Di Battistini G (1992) Isotope–geochemical effects of water–rock interactions in the Atesina-Cima d’Asta volcano-plutonic complex, Italy. In: Kharaka YK, Maest AS (eds) Water–rock interaction. Balkeema, Rotterdam, pp 989–994
Barth S, Oberli F, Meier M, Blattner P, Bargossi GM, Di Battistini G (1993) The evolution of a calc-alkaline basic to silicic magma system: geochemical and Rb–Sr, Sm–Nd, and 18O/16O isotopic evidence from the Late Hercynian Atesina-Cima d’Asta volcano–plutonic complex, northern Italy. Geochim Cosmochim Acta 57:4285–4300
Barth S, Oberli F, Meier M (1994) Th–Pb versus U–Pb isotope systematics in allanite from co-genetic rhyolite and granodiorite: implications for geochronology. Earth Planet Sci Lett 124:149–159
Bertotti G (1991) Early Mesozoic extension and Alpine shortening in the western Southern Alps: the geology of the area between Lugano and Menaggio (Lombardy, Northern Italy). Mem Sci Geol (Padova) 43:17–123
Bertotti G, Picotti V, Bernoulli D, Castellarin A (1993) From rifting to drifting: tectonic evolution of the South-Alpine upper crust from the Triassic to the Early Cretaceous. Sed Geol 86:53–76
Blichert-Toft J, Albarède F (1997) The Lu–Hf isotope geochemistry of chondrites and the evolution of the mantle-crust system. Earth Planet Sci Lett 148:243–258
Blichert-Toft J, Chauvel C, Albarède F (1997) Separation of Hf and Lu for high-precision isotope analysis of rock samples by magnetic sector-multiple collector ICP-MS. Contrib Mineral Petrol 127:248–260
Boriani A, Villa IM (1997) Geochronology of regional metamorphism in the Ivrea-Verbano Zone and Serie dei Laghi, Italian Alps. Schweiz Miner Petrogr Mitt 77:381–401
Boriani A, Burlini L, Caironi V, Giobbi Origoni E, Sassi A, Sesana E (1988) Geological and petrological studies on the Hercynian plutonism of Serie dei Laghi. Geological map of its occurrence between Valsesia and Lago Maggiore (N-Italy). Rend Soc Ital Miner Petrol 43:367–384
Boriani A, Burlini L, Sacchi R (1990) The Cossato–Mergozzo–Brissago Line and the Pogallo Line (Southern Alps, Northern Italy) and their relationships with the late-Hercynian magmatic and metamorphic events. Tectonophysics 182:92–102
Boriani A, Giobbi Origoni E, Pinarelli L (1995) Paleozoic evolution of southern Alpine crust (northern Italy) as indicated by contrasting granitoid suites. Lithos 35:47–63
Borsi S, D’ Amico C, Del Moro A (1974) Studio radiometrico delle rocce intrusive del massiccio di Cima d’Asta (Trentino). Mem Soc Geol Ital 13:145–159
Brack P, Schaltegger U (1999) Magmatism and extension in the Lower Permian of the Southern Alps: new age constraints from high-resolution U–Pb dating of zircons. In: International field conference “The Permian of the Southern Alps and Sardinia (Italy)”, Brescia, 15–19 September 1999 (Abstr vol)
Brack P, Rieber H, Urlichs M (1999) Pelagic successions in the Southern Alps and their correlation with the Germanic Middle Triassic. Zbl Geol Paläont Teil I (1998/7-8):853–876
Brack P, Rieber H, Nicora A, Mundil R (2005) The global boundary Stratotype Section and Point (GSSP) of the Ladinian Stage (Middle Triassic) at Bagolino (Southern Alps, Northern Italy) and its implications for the Triassic time scale. Episodes 28:233–244
Breitkreuz C, Cortesogno L, Gaggero L (2001) Crystal-rich mass flow deposits related to the eruption of a sublacustrine cryptodome (Early Permian Collio Basin, Italian Alps). J Volcanol Geotherm Res 114:373–390
Buletti M (1985) Petrographisch-geochemische Untersuchungen im Luganer Porphyrgebiet. Ph.D. thesis, University of Bern, pp 157 (in press)
Bürgi A, Klötzli U (1990) New data on the evolutionary history of the Ivrea zone (Northern Italy). Bull Swiss Assoc Petr Geol Eng 130:49–70
Bussy F, Venturini G, Hunziker J, Martinotti G (1998) U–Pb ages of magmatic rocks of the western Austroalpine Dent-Blanche-Sesia Unit. Schweiz Mineral Petrogr Mitt 78:163–168
Cadel G, Fuchs Y, Meneghel L (1987) Uranium mineralization associated with the evolution of a Permo-carboniferous volcanic field—examples from Novazza and Val Vedello (northern Italy). Uranium 3:407–421
Cadel G, Cosi M, Pennacchioni G, Spalla MI (1996) A new map of the Permo-Carboniferous cover and Variscan metamorphic basement in the central Orobic Alps, Southern Alps—Italy: structural and stratigraphical data. Mem Sci Geol (Padova) 48:1–53
Cassinis G, Ronchi A (2001) Permian chronostratigraphy of the Southern Alps (Italy)—an update. In: Weiss RH (ed) Contributions to geology and paleontology of Gondwana in honour of Helmut Wopfner. Geol Inst Cologne, pp 73–88
Cassinis G, Massari F, Neri C, Venturini C (1988) The continental Permian in the Southern Alps. Z Geol Wiss 16:1117–1126
Cassinis G, Perotti CR, Venturini C (1997) Examples of late Hercynian transtensional tectonics in the Southern Alps (Italy). In: Dickins JM (ed) Late Paleozoic and early Mesozoic Circum-Pacific events and their global correlation, vol 10. Cambridge University Press, World and Regional Geology, pp 41–49
Cortesogno L, Fiorini E, Gaggero L, Molina M, Ronchi A (1998) New stratigraphic and petrographic data on the Permian Tione basin (Lower Val Rendena, Trentino, Italy). Atti Tic Sc Terra (Serie speciale) 7:125–138
Dal Piaz GV, Martin S (1998) Evoluzione litosferica e magmatismo nel dominio Austro-Sudalpino dall’orogenesi varisica al rifting mesozoico. Mem Soc Geol Ital 53:43–62
De Capitani L, Delitalia MC, Liborio G, Mottana A, Rodeghiero F, Thöni M (1994) The granitoid rocks of Val Navazze, Val Torgola and Val di Rango (Val Trompia, Lombardy, Italy). Mem Sci Geol (Padova) 46:329–343
Del Moro A, Visonà D (1982) The epiplutonic Hercynian complex of Bressanone (Brixen, eastern Alps, Italy); Petrologic and radiometric data. N Jb Miner Abh 145:66–85
Demarchi G, Quick JE, Sinigoi S, Mayer A (1998) Pressure gradient and original orientation of a lower-crustal intrusion in the Ivrea-Verbano zone, Northern Italy. J Geol 106:609–622
Desmurs L, Manatschal G, Bernoulli D (2001) The Steinmann Trinity revised: mantle exhumation and magmatism along an ocean-continent transition: the Platta nappe, eastern Switzerland. In: Wilson RCL, Whitmarsh RB, Taylor B, Froitzheim N (eds) Non-volcanic rifting of continental margins: a comparison of evidence from land and sea, vol 187. Geol Soc London Spec Pub, pp 235–266
Fountain DM (1976) The Ivrea-Verbano and Strona-Ceneri Zones, Northern Italy: a cross section of the continental crust—new evidence from seismic velocities of rock samples. Tectonophysics 33:145–165
Gansser A, Pantic N (1988) Prealpine events along the eastern Insubric Line (Tonale Line, Northern Italy). Eclogae Geol Helv 81:567–577
Garuti G, Bea F, Zaccarini F, Monetero P (2001) Age, geochemistry and petrogenesis of the ultramafic pipes in the Ivrea Zone, NW Italy. J Petrol 42:433–457
Gradstein FM, Ogg JG, Smith AG, Bleeker W, Lourens LJ (2004) A new geologic time scale, with special reference to Precambrian and Neogene from the Dabie Mountains, central China. Episodes 27:83–100
Grieco G, Ferrario A, von Quadt A, Köppel V, Mathez EA (2001) The zircon-bearing chromitites of the phlogopite peridotite of Finero (Ivrea Zone, Southern Alps): evidence and geochronology of a metasomatized mantle slab. J Petrol 42:89–101
Handy MR (1987) The structure, age and kinematics of the Pogallo Fault Zone; Southern Alps, northwestern Italy. Eclogae Geol Helv 80:593–632
Handy MR, Streit JE (1999) Mechanics and mechanisms of magmatic underplating: inferences from mafic veins in deep crustal mylonite. Tectonophysics 165:271–286
Handy MR, Zingg A (1991) The tectonic and rheological evolution of an attenuated cross section of the continental crust: Ivrea crustal section, southern Alps, northwestern Italy and southern Switzerland. Geol Soc Am Bull 103:236–253
Handy MR, Franz L, Heller B, Janott B, Zurbriggen R (1999) Multistage accretion and exhumation of the continental crust (Ivrea crustal section, Italy and Switzerland). Tectonics 18:1154–1177
Hansmann W, Müntener P, Hermann J (2001) U–Pb zircon geochronology of a tholeitic intrusion and associated migmatites at a continental crust–mantle transition, Val Malenco, Italy. Schweiz Mineral Petrogr Mitt 81:239–255
Henk A, Leander F, Teufel S, Oncken O (1997) Magmatic underplating, extension and crustal reequilibration: Insights from a cross-section through the Ivrea Zone and Strona-Ceneri Zone, Northern Italy. J Geol 105:367–377
Hermann J, Müntener O, Trommsdorff V, Hansmann W, Piccardo GB (1997) Fossil crust-to-mantle transition, Val Malenco (Italian Alps). J Geophys Res 102(B9):20123–20132
Hermann J, Müntener O, Günther D (2001) Differentiation of mafic magma in a continental crust-to-mantle transition zone. J Petrol 42:189–206
Hess JC (1990) Numerische Stratigraphie permokarbonischer Vulkanite Zentraleuropas. Allgemeine Einführung und Teil I: Südtirol. Z Dt Geol Ges 141:1–11
Hodges KV, Fountain DM (1984) Pogallo Line, South Alps, northern Italy; An intermediate crustal level, low-angle normal fault? Geology 12:151–155
Hunziker JC, Zingg A (1980) Lower Paleozoic amphibolite to granulite facies metamorphism in the Ivrea-Zone (Southern Alps–Northern Italy). Schweiz Mineral Petrogr Mitt 60:181–213
Irving E (1977) Drift of the major continental blocks since the Devonian. Nature 270:304–309
Jongmans W (1960) Die Karbonflora der Schweiz. Beitr Geol Karte Schweiz, NF 108:1–97
Kalvacheva R, Sassi FP, Zanferrari A (1986) Acritarch evidence for the Cambrian age of phyllites in the Agordo area (South-Alpine basement of Eastern Alps, Italy). Rev Palaeobot Palynol 48:311–326
Klötzli US, Mair V, Bargossi GM (2003) The “Bozener Quarzporphyr” (Southern Alps, Italy): single zircon U/Pb age evidence for 10 million years of magmatic activity in the Lower Permian. Mitt Oesterr Miner Ges 148:187–188
Köppel V (1974) Isotopic U–Pb ages of monazites and zircons from the crust–mantle transition and adjacent units of the Ivrea and Ceneri Zones (Southern Alps, Italy). Contrib Mineral Petrol 43:55–70
Läufer AL, Hubich D, Loeschke J (2001) Variscan geodynamic evolution of the Carnic Alps (Austria/Italy). Int J Earth Sci 90:855–870
Lowenstern JB, Persing HM, Wooden JL, Lanphere M, Donnelly-Nolan J, Grove TL (2000) U–Th dating of single zircons from young granitoid xenoliths: new tools for understanding volcanic processes. Earth Planet Sci Lett 183:291–302
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 (2000) Isoplot, ver 2.31: USGS Open-file
Marocchi M, Bargossi GM, Klötzli U, Mair V, Morelli C (2005) Zircon geochronology and a new stratigraphic systematic of the Lower Permian Athesian Volcanic Group (AG), Southern Alps (Italy). Epitome 2005, 1, Geoitalia 2005, abstract 21–6
Marroni M, Molli G, Ottria G, Pandolfi L (2001) Tectono-sedimentary evolution of the External Liguride units (Northern Apennines, Italy): insights in the pre-collisional history of a fossil ocean-continent transition zone. Geodin Acta 14:307–320
Martin S, Zattin M, Del Moro A, Macera P (1996) Chronologic constraints for the evolution of the Giudicarie belt (Eastern Alps, NE Italy). Ann Tectonicae 10:60–79
Mehnert KR (1975) The Ivrea Zone. A model of the deep crust. N Jb Miner Abh 125:156–199
Monjoie P (2004) The Mont Collon mafic complex (Austroalpine Dent Blanche nappe): permian evolution of the western European mantle. Ph.D. thesis, University Lausanne and Grenoble, pp 156
Monjoie P, Bussy F, Schaltegger U, Lapierre H, Pfeifer HR (2001) Permian mafic rocks in the Alps: a post-orogenic mantle melting event illustrated by the Mont Collon-Matterhorn intrusion (Austroalpine Dent Blanche nappe). EUG 11, Strasbourg. J Conf Abstr 6(1):475
Monjoie P, Bussy F, Schaltegger U, Mulch A, Lapierre H, Pfeifer HR (2007) Episodic activity in the Permian Layered Mafic Complex of Mont Collon (Western Alps, Wallis, Switzerland): evidence from U/Pb zircon and 40Ar/39Ar amphibole dating. Swiss J Geosci (in press)
Montanini A, Tribuzio R (2001) Gabbro-derived granulites from the Northern Apennines (Italy): evidence for lower-crustal emplacement of tholeiitic liquids in post-Variscan times. J Petrol 42:2259–2277
Mulch A, Rosenau M, Dörr W, Handy MR (2002) The age and structure of dikes along the tectonic contact of the Ivrea-Verbano and Strona-Ceneri Zones (southern Alps, Northern Italy, Switzerland). Schweiz Mineral Petrogr Mitt 82:55–76
Mundil R, Kudwig KR, Metcalfe I, Renne PR (2004) Age and timing of the Permian mass extinctions: U/Pb dating of closed-system zircons. Science 305:1760–1763
Müntener O, Desmurs L, Pettke T, Meier M, Schaltegger U (2004) Formation of fertile mantle in embryonic ocean basins controlled by melt/rock reaction. Earth Planet Sci Lett 221:239–308
Muttoni G, Kent DV, Garzanti E, Brack P, Abrahamsen N, Gaetani M (2003) Early Permian Pangea “B” to Late Permian Pangea “A”. Earth Planet Sci Lett 215:379–394
Neri C, Avanzini M, Bampi T, Bargossi GM, Mair V, Morelli C, Pittau P, Ronchi A, Sapelza A (1999) The Tregiovo area and related volcanics in the Tregiovo section. In: Cassinis G et al (eds) Stratigraphy and facies of the Permian deposits between eastern Lombardy and the western Dolomites—field trip guidebook, pp 81–89
Petford N, Cruden AR, Mc Caffrey KJW, Vigneresse JL (2000) Granite magma formation, transport and emplacement in the Earth’s crust. Nature 408:669–673
Philippe S, Villemaire C, Lancelot JR, Girod M, Mercadier H (1987) Données minéralogiques et isotopiques sur deux gîtes hydrothermaux uranifères du bassin volcano-sédimentaire permien de Collio Orobico (Alpes Bergamasques): mise en évidence d’une phase de remobilisation crétacée. Bull Minéral 110:283–303
Pin C (1986) Datation U–Pb sur zircons à 285 M.a. du complexe gabbro-dioritique du Val Sesia-Val Mastallone et âge tardi-hercynien du métamorphisme granulitique de la zone Ivrea-Verbano (Italie). C R Acad Sci 303/2:827–830
Pinarelli L, Del Moro A, Boriani A (1988) Rb–Sr geochronology of Lower Permian plutonism in Massiccio dei Laghi, Southern Alps (NW Italy). Rend Soc Ital Miner Petr 43:411–428
Pinarelli L, Boriani A, Del Moro A (1993) The Pb isotopic systematics during crustal contamination of subcrustal magmas: the Hercynian magmatism of the Serie dei Laghi (Southern Alps, Italy). Lithos 31:51–61
Pinarelli L, Del Moro A, Boriani A, Caironi V (2002) Sr, Nd isotope evidence for an enriched mantle component in the origins of the Hercynian gabbro-granite series of the “Serie dei Laghi” (Southern Alps, NW Italy). Eur J Mineral 14:403–415
Pupin JP (1980) Zircon and granite petrology. Contrib Mineral Petrol 73:207–220
Quick JE, Sinigoi S, Mayer A (1994) Emplacement dynamics of a large mafic intrusion in the lower crust, Ivrea-Verbano zone, northern Italy. J Geophys Res 99(B11):21559–21573
Quick JE, Sinigoi S, Snoke AW, Kalakay TJ, Mayer A, Peressini G (2003) Geologic map of the southern Ivrea-Verbano Zone, Northwestern Italy. Geologic Inverstigations Series map I-2776 USGS, map + pamphlet, pp 22
Rampone E, Hofmann AW, Raczek I (1998) Isotopic contrasts within the Internal Liguride ophiolite (N. Italy): the lack of a genetic mantle-crust link. Earth Planet Sci Lett 163:175–189
Rebay G, Spalla MI (2001) Emplacement at granulite facies conditions of the Sesia-Lanzo metagabbros: an early record of Permian rifting? Lithos 58:85–104
Rivalenti G, Rossi A, Siena F, Sinigoi S (1984) The layered series of the Ivrea-Verbano igneous complex, western Alps, Italy. Tschermaks Miner Petrogr Mitt 33:77–99
Rottura A, Bargossi GM, Caggianelli A, Del Moro A, Visonà D, Tranne CA (1998) Origin and significance of the Permian high-K calc-alkaline magmatism in the central–eastern Southern Alps, Italy. Lithos 45:329–348
Rutter EH, Brodie KH, Evans PJ (1993) Structural geometry, lower crustal magmatic underplating and lithospheric stretching in the Ivrea-Verbano zone, northern Italy. J Struct Geol 15:647–662
Rutter EH, Khazanehdari J, Brodie KH, Blundell D, Waltham DA (1999) Synthetic seismic reflection profile through the Ivrea zone—Serie dei Laghi continental crustal section, northwestern Italy. Geology 27:79–82
Rutter EH, Brodie K, James T, Blundell DJ, Waltham DA (2003) Seismic modeling of lower and mid-crustal structure as exemplified by the Massiccio dei Laghi (Ivrea-Verbano zone and Serie dei Laghi) crustal section, N.W. Italy. In: Goff JA, Holliger K (eds) Heterogeneity in the crust and upper mantle: nature, scaling, and seismic properties. Kluwer, New York, pp 67–99
Schaltegger U, Brack P (1999) Short-lived events of extension and volcanism in the Lower Permian of the Southern Alps (northern Italy, southern Switzerland). J Conf Abstr 4(1):296–297
Schaltegger U, Desmurs L, Manatschal G, Müntener O, Meier M, Frank M, Bernoulli D (2002) From a rifted continental margin to a slow spreading system: field and isotopic constraints. Terra Nova 14:156–162
Schmid R, Wood BJ (1976) Phase relationships in granulitic metapelites from the Ivrea-Verbano zone (Northern Italy). Contrib Mineral Petrol 54:255–279
Schmid SM, Zingg A, Handy MR (1987) The kinematics of movements along the Insubric Line and the emplacement of the Ivrea Zone. Tectonophysics 135:47–66
Schnetger B (1994) Partial melting during the evolution of the amphibolite- to granulite-facies gneisses of the Ivrea Zone, northern Italy. Chem Geol 113:71–101
Sciunnach D (2001a) The Lower Permian in the Orobic Anticline (Southern Alps, Lombardy): a review based on new stratigraphic and petrographic data. Riv Ital Paleont Stratigr 107:47–68
Sciunnach D (2001b) Benthic foraminifera from the upper Collio Formation (Lower Permian, Lombardy Southern Alps): implications for the palaeography of the peri-Tethyan area. Terra Nova 13:150–155
Selli L, Bargossi GM, Di Battistini G, Mordenti A, Tranne CA, Stefani A (1996) Le vulcaniti permiane a N della Linea del Calisio: evoluzione strutturale del margine SW del distretto vulcanico atesino (Trento, Italia). Miner Petrogr Acta 39:169–196
Sinigoi S, Quick JE, Clemens-Knott D, Mayer A, Demarchi G, Mazzucchelli M, Negrini L, Rivalenti G (1994) Chemical evolution of a large mafic intrusion in the lower crust, Ivrea-Verbano Zone, northern Italy. J Geophys Res 99(B11):21575–21590
Snoke AW, Kalakay TJ, Quick JE, Sinigoi S (1999) Development of a deep-crustal shear zone in response to syntectonic intrusion of mafic magma into the lower crust, Ivrea-Verbano zone, Italy. Earth Planet Sci Lett 166:31–45
Stacey JS, Kramers JD (1975) Approximation of terrestrial lead isotope evolution by a two-stage model. Earth Planet Sci Lett 26:207–221
Stille P, Buletti M (1987) Nd–Sr isotopic characteristics of the Lugano volcanic rocks and constraints on the continental crust formation in the South Alpine domain (N-Italy—Switzerland). Contrib Mineral Petrol 96:140–150
Stille P, Schaltegger U (1996) The lithospheric mantle beneath Central Europe: Nd isotopic constraints for its Late Proterozoic enrichment and implications for early crustal evolution. In: Basu A, Hart SR (eds) Earth processes: reading the isotopic code, vol 95. Am Geophys Union, Washington, Geophys Monogr Ser, pp 269–276
Stille P, Steiger RH (1991) Hf isotope systematics in granitoids from the Central and Southern Alps. Contrib Mineral Petrol 107:273–278
Stöckhert B, Sigmund J, Hammerschmidt K, Flisch M (1990) The Astjoch diorite—a shallow calc-alkaline intrusion of Permian age in the basement of the Southern Alps. Terra Abstr 2:26
Tribuzio R, Thirlwall MF, Messiga B (1999) Petrology, mineral and isotope geochemistry of the Sondalo gabbroic complex (Central Alps, Northern Italy): implications for the origin of post-Variscan magmatism. Contrib Mineral Petrol 136:48–62
Vavra G, Schaltegger U (1999) Post-granulite facies monazite growth and rejuvenation during Permian to Lower Jurassic thermal and fluid events in the Ivrea Zone (Southern Alps). Contrib Mineral Petrol 134:405–414
Vavra G, Gebauer D, Schmid R, Compston W (1996) Multiple zircon growth and recrystallization during polyphase Late Carboniferous to Triassic metamorphism in granulites of the Ivrea zone (Southern Alps): an ion microprobe (SHRIMP) study. Contrib Mineral Petrol 122:337–358
Vavra G, Schmid R, Gebauer D (1999) Internal morphology, habit and U–Th–Pb microanalysis of amphibolite-to-granulite facies zircons: geochronology of the Ivrea Zone (Southern Alps). Contrib Mineral Petrol 134:380–404
Venturini C, Spalletta C (1998) Remarks on the Paleozoic stratigraphy and the Hercynian tectonics of the Palaeocarnic chain (Southern Alps). Giorn Geol, ser 3a, 60, Spec Issue, ECOS VII Southern Alps Field Trip Guidebook, pp 69–88
Visonà D, Fioretti AM, Poli ME, Zanferrari A, Fanning M (2005) Geochronologial evidence for onset of Permian volcanism in the eastern southalpine (NE Italy). Epitome 2005, 1, Geoitalia 2005, abstr 44–21
Voshage H, Hofmann AW, Mazzucchelli M, Rivalenti G, Sinigoi S, Demarchi G. (1990) Isotopic evidence from the Ivrea zone for a hybrid lower crust formed by magmatic underplating. Nature 347:731–736
Zingg A (1980) Regional metamorphism in the Ivrea Zone (southern Alps, N-Italy): Field and microscopic investigations. Schweiz Mineral Petrogr Mitt 60:153–179
Zingg A (1990) The Ivrea crustal cross-section (northern Italy and southern Switzerland). In: Salisbury MH, Fountain DM (eds) Exposed cross-sections of the continental crust, vol 317. NATO ASI Ser, Ser C, pp 1–20
Zingg A, Handy MR, Hunziker JC, Schmid SM (1990) Tectonometamorphic history of the Ivrea Zone and its relationship to the crustal evolution of the Southern Alps. Tectonophysics 182:169–192
Zurbriggen R, Franz L, Handy MR (1997) Pre-Variscan deformation, metamorphism and magmatism in the Strona-Ceneri Zone (southern Alps of northern Italy and southern Switzerland). Schweiz Mineral Petrogr Mitt 77:361–380
Acknowledgments
We thank I. Ivanov, Th. Bär, D. Seward, W. Witwer and A. von Quadt for help with sample preparation and mass spectrometry and F. Maurer for assistance in sample acquisition. Hafnium isotopic determinations by M. Frank are gratefully acknowledged. M. Buletti helped with maps and the bibliography of the Lugano area. The late R. H. Steiger kindly donated zircons of the sample of Montorfano granite SA-1; this paper is dedicated to his memory. L. Burlini’s input and help with the Ivrea cross-section and comments by D. Chew are highly appreciated. Comments and suggestions by D. Bernoulli and reviewers G. M. Bargossi and M. R. Handy helped to improve and clarify the manuscript.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Schaltegger, U., Brack, P. Crustal-scale magmatic systems during intracontinental strike-slip tectonics: U, Pb and Hf isotopic constraints from Permian magmatic rocks of the Southern Alps. Int J Earth Sci (Geol Rundsch) 96, 1131–1151 (2007). https://doi.org/10.1007/s00531-006-0165-8
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00531-006-0165-8