Contributions to Mineralogy and Petrology

, Volume 92, Issue 4, pp 413–427 | Cite as

Cooling and uplift patterns in the Lepontine Alps South Central Switzerland and an age of vertical movement on the Insubric fault line

  • Anthony J. Hurford


96 new fission track (FT) apatite and zircon, K/Ar and Rb/Sr biotite and muscovite ages are presented for 19 samples (mainly acid gneisses) from a 40 km traverse through the Lepontine Alps in the Maggia Valley, South Central Switzerland. Plotting measured mineral ages against assumed system closure temperatures yields cooling rates for each sample. The entire profile shows a fairly uniform Late Neogene-Recent mean uplift rate of ∼0.5 mm/a, confirmed by a gradient of FT apatite age with elevation. Cooling from higher temperatures occurred earlier in the south, where uplift rates of ∼2.2 mm/a in the Steep Belt (root zone) indicate >9 km Early Miocene uplift of the northern Pennine block. This uplift started before 23 Ma and is interpreted as resulting from a major phase of backthrusting along the Insubric Line, and as dating the formation of the mylonite belt. Estimated cooling rates constrain the timing of Lepontine Mid-Tertiary metamorphism: 3 schematic models are proposed which also consider published Rb/Sr, K/Ar mica and hornblende and U/Pb monazite ages. Slow cooling, differential initial heating and subsequent cooling of different parts of the Central Alps and post-38 Ma cooling with syntectonic metamorphism at ∼27 Ma are postulated as alternative interpretations of isotopic data and geologic evidence. From extrapolation between K/Ar and Rb/Sr mica ages and apatite FT ages, 240±50° C is proposed as the closure temperature for the retention of fission tracks in zircon.


Apatite Fission Track Closure Temperature South Central Uplift Rate 
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  1. Ayrton SN, Ramsay JG (1974) Tectonic and metamorphic events in the Alps. Schweiz Mineral Petrogr Mitt 54:609–639Google Scholar
  2. Bearth P (1958) Über einen Wechsel der Mineralfazies in der Wurzelzone des Penninikums. Schweiz Mineral Petrogr Mitt 38:363–373Google Scholar
  3. Berger GW, York D (1981) Geothermometry from 40Ar/39Ar dating experiments. Geochim Cosmochim Acta 45:795–811Google Scholar
  4. Bernoulli D, Lemoine M (1980) Birth and early evolution of the Tethys: the overall situation. In: Geology of the Alpine Chains born of Tethys. 26th Int Geol Cong ParisGoogle Scholar
  5. Bigioggero B, Boriani A, Colombo A, Tunesi A (1981) Eta'e caratteri petrochimica degli ortogneiss della zona Moncucco-Orselina nell'area Ossolana. Rendiconti 38:207–218Google Scholar
  6. Clark SP, Jäger E (1969) Denudation rate in the Alps from geochronologic and heat flow data. Am J Sci 267:1143–1160Google Scholar
  7. Dallmeyer RD (1978) 40Ar/39Ar incremental release ages of hornblende and biotite across the Georgia Inner Piedmont: their bearing on Late Palaeozoic-Early Mesozoic tectono-thermal history. Am J Sci 278:124–149Google Scholar
  8. Dal Piaz GV, Hunziker JC, Martinotti G (1972) La Zona Sesia-Lanzo e l'evoluzione tettonico-metamorfica delle Alpi nordoccidentali interni. Mem Geol Soc Ital 11:433–460Google Scholar
  9. Dempster TJ (1985) Uplift patterns and orogenic evolution in the Scottish Dalradian. J Geol Soc London 142:111–128Google Scholar
  10. Deutsch A, Steiger RH (1985) Hornblende K/Ar ages and the climax of Tertiary metamorphism in the Lepontine Alps (South Central Switzerland): an old problem reassessed. Earth Planet Sci Letts 72:175–189Google Scholar
  11. Dewey JF, Bird JM (1970) Mountain belts and the new global tectonics. J Geophys Res 75:2625–2647Google Scholar
  12. Fleischer RL, Hart HR (1972) Fission track dating: techniques and problems. In: Bishop WW, Miller JA (eds) Calibration of hominoid evolution. Scott Acad Press, Edinburgh, pp 135–170Google Scholar
  13. Fleischer RL, Price PB, Walker RM (1965) Effects of temperature, pressure and ionization on the formation and stability of fission tracks in minerals and glasses. J Geophys Res 70:1497–1502Google Scholar
  14. Flisch M (1982) Potassium argon analysis. In: Odin GS (ed) Numerical dating in stratigraphy. John Wiley, Chichester, pp 151–158Google Scholar
  15. Frey M, Bucher K, Frank E, Mullis J (1980) Alpine metamorphism along the geotraverse Basel-Chiasso — a review. Eclogae Geol Helv 73:527–546Google Scholar
  16. Galbraith RF (1981) On statistical models for fission track counts. Math Geol 13:471–488Google Scholar
  17. Gansser A (1968) The Insubric Line — a major geotectonic problem. Schweiz Mineral Petrogr Mitt 48:123–143Google Scholar
  18. Gleadow AJW (1981) Fission track dating methods: what are the real alternatives? Nucl Tracks 5:3–14Google Scholar
  19. Gleadow AJW, Brooks CK (1979) Fission track dating, thermal histories and tectonics of igneous intrusions in East Greenland. Contrib Mineral Petrol 71:45–60Google Scholar
  20. Gleadow AJW, Duddy IR (1981) A long-term track annealing experiment for apatite. Nucl Tracks 5:169–174Google Scholar
  21. Gleadow AJW, Lovering JF (1977) Geometry factor for external detectors in fission track dating. Nucl Track Detection 1:99–106Google Scholar
  22. Gleadow AJW, Duddy IR, Lovering JF (1983) Fission track analysis: a new tool for the evaluation of thermal histories and hydrocarbon potential. Austral Petrol Explor Assoc J 23:93–102Google Scholar
  23. Gleadow AJW, Hurford AJ, Quaife DR (1976) Fission track dating of zircon — improved etching techniques. Earth Planet Sci Letts 33:273–276Google Scholar
  24. Green PF (1981) A new look at statistics in fission track dating. Nucl Tracks 5:77–86Google Scholar
  25. Gulson BL (1973) Age relations in the Bergell region of the South-East Swiss Alps: with some geochemical comparisons. Eclogae Geol Helv 66:293–313Google Scholar
  26. Haack U (1977) The closing temperature for fission track retention in minerals. Am J Sci 277:459–464Google Scholar
  27. Hanson GN, Gast PW (1967) Kinetic studies in contact metamorphic zones. Geochim Cosmochim Acta 31:1119–1153Google Scholar
  28. Harrison TM, McDougall I (1980) Investigations of an intrusive contact, northwest Nelson, New Zealand I: Thermal, chronological and isotopic constraints. Geochim Cosmochim Acta 44:1985–2003Google Scholar
  29. Harrison TM, Armstrong RL, Naeser CW, Harakal JE (1979) Geochronology and thermal history of the Coast Plutonic complex, near Prince Rupert BC Can J Earth Sci 16:400–410Google Scholar
  30. Heitzmann P (1975) Zur Metamorphose und Tektonik im südöstlichen Teil der Lepontinischen Alpen. Schweiz Mineral Petrogr Mitt 55:467–522Google Scholar
  31. Hunziker JC (1969) Rb/Sr Altersbestimmungen aus den Walliser Alpen Hellglimmer- und Gesamtgesteinsalterwerte. Eclogae Geol Helv 62:527–542Google Scholar
  32. Hunziker JC (1970) Polymetamorphism in the Monte Rosa, Western Alps. Eclogae Geol Helv 63:151–161Google Scholar
  33. Hunziker JC (1974) Rb/Sr and K/Ar age determination and the Alpine tectonic history of the Western Alps. Mem Ist Geol Mineral Univ Padova, 31Google Scholar
  34. Hurford AJ, Green PF (1982) A users' guide to fission track dating calibration. Earth Planet Sci Letts 59:343–354Google Scholar
  35. Hurford AJ, Green PF (1983) The zeta age calibration of fission track dating. Isot Geosci 1:285–317Google Scholar
  36. Jäger E (1970) Rb/Sr systems in different degrees of metamorphism. Eclogae Geol Helv 63:163–172Google Scholar
  37. Jäger E (1973) Die alpine Orogenese im Lichte der radiometrischen Altersbestimmung. Eclogae Geol Helv 66:11–21Google Scholar
  38. Jäger E (1979) Introduction to geochronology. In: Jäger E, Hunziker JC (eds) Lectures in isotope geology. Springer, Berlin Heidelberg New York, pp 1–12Google Scholar
  39. Jäger E, Niggli E, Wenk E (1967) Rb/Sr Altersbestimmungen an Glimmern der Zentralalpen. Beitr Geol Karte Schweiz NF 134, pp 67Google Scholar
  40. Jäger E, Hunziker JC, Graeser S, Grünenfelder M (1969) Unpublished Field Guide for Coll. on Geochron. Phanerozoic Orogenic Belts, SwitzerlandGoogle Scholar
  41. Jeanrichard F (1975) Summary of geodetic studies of recent crustal movements in Switzerland. Tectonophysics 29:289–292Google Scholar
  42. Köppel V, Grünenfelder M (1975) Concordant U/Pb ages of monazite and xenotime from the Central Alps and the timing of high temperature Alpine metamorphism: a preliminary report. Schweiz Mineral Petrogr Mitt 55:129–132Google Scholar
  43. Köppel V, Grünenfelder M (1978) The significance of monazite U/Pb ages: examples from the Lepontine area of the Swiss Alps. In: Zartman RE (ed) Short papers of the 4th Int Conf Geochron Cosmochron Isotope Geol US Geol Surv Open File Report 78-701, pp 226–227Google Scholar
  44. Krishnaswami S, Lal D, Prabhu N, MacDougall D (1974) Characteristics of fission tracks in zircon: applications to geochronology and cosmology. Earth Planet Sci Letts 22:51–59Google Scholar
  45. Lal D, Murali AV, Rajan RS, Tamhane AS, Lorin JC, Pellas P (1968) Techniques for proper revelation and viewing of etch tracks in meteoritic and terrestrial materials. Earth Planet Sci Letts 5:111–119Google Scholar
  46. Milnes AG (1974) Structure of the Pennine zone (Central Alps): a new working hypothesis. Bull Geol Soc Am 85:1727–1732Google Scholar
  47. Milnes AG (1978) Structural zones and continental collision, Central Alps. Tectonophysics 47:369–392Google Scholar
  48. Milnes AG, Pfiffner OA (1977) Structural development of the Infrahelvetic complex, Eastern Switzerland. Eclogae Geol Helv 70:83–95Google Scholar
  49. Naeser CW (1979) Fission track dating and geologic annealing of fission tracks. In: Jäger E, Hunziker JC (eds) Lectures in Isotope Geology. Springer, Berlin Heidelberg New York, pp 154–169Google Scholar
  50. Naeser CW, Faul H (1969) Fission track annealing in apatite and sphene. J Geophys Res 74:705–710Google Scholar
  51. Naeser CW, Izett GA, Obradovich JD (1980) Fission track and K/Ar ages of natural glasses. Bull US Geol Surv 1489, pp 31Google Scholar
  52. Neugebauer HJ, Brotz R, Rybach L (1980) Recent crustal uplift and the present stress field of the Alps along the Swiss Geotraverse Basel-Chiasso. Eclogae. Geol Helv 73:489–500Google Scholar
  53. Niggli E (1970) Alpine Metamorphose und alpine Gebirgsbildung. Fortschr Mineral 47:16–26Google Scholar
  54. Purdy JW, Jäger E (1976) K/Ar ages on rock-forming minerals from the Central Alps. Mem Ist Geol Mineral Univ Padova, 30Google Scholar
  55. Rybach L, Müller S, Milnes AG, Ansorge J, Bernoulli D, Frey M (1980) The Swiss geotraverse Basel-Chiasso — a review. Eclogae Geol Helv 73:437–462Google Scholar
  56. Schaer JP, Reimer GM, Wagner GA (1975) Actual and ancient uplift rate in the Gotthard region, Swiss Alps: a comparison between precise levelling and fission track apatite age. Tectonophysics 29:293–300Google Scholar
  57. Schmid SM, Zingg A, Handy M (1986) The kinematics of movements along the Insubric Line and the emplacement of the Ivrea zone (in press)Google Scholar
  58. Schumacher E (1975) Herstellung von >99.9997% 38Ar für die 40K/40Ar Geochronologie. Chimia 29:441–442Google Scholar
  59. Siegenthaler R (1984) Alter und Geochemie von Glimmern und Feldspäten. Unpublished doctoral thesis, University of BerneGoogle Scholar
  60. Steiger R (1964) Dating of orogenic phases in the Central Alps by K/Ar ages of hornblende. J Geophys Res 69:5407–5421Google Scholar
  61. Steiger RH, Jäger E (1977) Subcommission on geochronology: convention on the use of decay constants in geo- and cosmochronology. Earth Planet Sci Lett 36:359–362Google Scholar
  62. Steinitz G, Jäger E (1981) Rb/Sr and K/Ar studies on rocks from the Suretta nappe, Eastern Switzerland. Schweiz Mineral Petrogr Mitt 61:121–131Google Scholar
  63. Trümpy R (1975) On crustal subduction in the Alps. In: Mahel M (ed) Tectonic problems of the Alpine system. Slovak Acad Sci, Bratislava, pp 121–130Google Scholar
  64. Trümpy R (1980) Geology of Switzerland — a guide book. Part A: An outline of the geology of Switzerland. Wepf, Basel, pp 104Google Scholar
  65. Turner DL, Forbes RB (1976) K/Ar studies in two deep basement drillholes: a new estimate of argon blocking temperature for biotite. Trans Am Geophys Union 57:353Google Scholar
  66. Verschure RH, Andriessen PAM, Boelrijk NAIM, Hebeda EH, Maijer C, Priem HNA, Verdurmen EATh (1980) On the thermal stability of Rb/Sr and K/Ar biotite systems: evidence from coexisting Sveconorwegian (ca 870 Ma) and Caledonian (ca 400 Ma) biotites in SW Norway. Contrib Mineral Petrol 74:245–252Google Scholar
  67. Vogler WS, Voll G (1981) Deformation and metamorphism at the south margin of the Alps, East of Bellinzona, Switzerland. Geol Rund 70:1232–1262Google Scholar
  68. Wagner GA (1968) Fission track dating of apatites. Earth Planet Sci Lett 4:411–415Google Scholar
  69. Wagner GA (1969) Spuren der spontanen Kernspaltung des 238Urans als Mittel zur Datierung von Apatiten und ein Beitrag zur Geochronologie des Odenwaldes. N Jahrb Mineral Abh 110:252–286Google Scholar
  70. Wagner GA, Reimer GM (1972) Fission track tectonics: the tectonic interpretation of fission track apatite ages. Earth Planet Sci Lett 14:263–268Google Scholar
  71. Wagner GA, Reimer GM, Jäger E (1977) Cooling ages derived by apatite fission track, mica Rb/Sr and K/Ar dating: the uplift and cooling history of the Central Alps. Mem Ist Geol Mineral Univ Padova, 30Google Scholar
  72. Wenk E, Keller F (1969) Isograde in Amphibolitserien der Zentralalpen. Schweiz Mineral Petrogr Mitt 49:157–198Google Scholar
  73. Werner D (1980) Probleme der Geothermik im Bereich der Schweizer Zentralalpen. Eclogae Geol Helv 73:513–525Google Scholar
  74. Zeitler P, Tahirkheli RAK, Naeser CW, Johnson NM (1982) Unroofing history of a suture zone in the Himalaya of Pakistan by means of fission track annealing ages. Earth Planet Sci Lett 57:227–240Google Scholar
  75. Zingg A (1983) The Ivrea and Strona-Ceneri Zones (Southern Alps, Ticino and N. Italy) — a review. Schweiz Mineral Petrogr Mitt 63:361–392Google Scholar

Copyright information

© Springer-Verlag 1986

Authors and Affiliations

  • Anthony J. Hurford
    • 1
  1. 1.Laboratory for Isotope GeologyUniversity of BerneBerneSwitzerland

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