Contributions to Mineralogy and Petrology

, Volume 120, Issue 2, pp 197–211 | Cite as

Anticorrelated Rb−Sr and K−Ar age discordances, Leuchtenberg granite, NE Bavaria, Germany

  • Wolfgang Siebel


The Leuchtenberg granite (Oberpfalz, NE Bavaria) displays a continuous differentiation trend ranging from mildy peraluminous, coarse-grained, porphyritic biotite granites (BG) to strongly peraluminous, medium- to fine-grained, garnet-bearing muscovite granites (GMG). The Rb−Sr and K−Ar age determinations of whole-rock and mineral samples from the granite and associated intermediate rocks (redwitzites) have revealed two divergent age gradients: Rb−Sr wholerock dates decrease and initial 87Sr/86Sr ratios increase for successively more evolved subsets of the granite. All BG samples (87Rb/86Sr=2–16) yield a date of 326±2 Ma with a low initial 87Sr/86Sr ratio of 0.70778±0.00013 (1ϖ), while all GMG samples (87Rb/86Sr=70 to 1000) yield a younger date of 317±2 Ma with an enhanced initial 87Sr/86Sr ratio of 0.7146±0.0039. The K−Ar measurements on biotites and muscovites give closely concordant dates for the GMG (326–323 Ma) and the southern lobe of the BG (324–320 Ma). The northern lobe of the BG, including the redwitzites, shows a well-defined trend of decreasing K−Ar dates from 320 Ma to 300 Ma towards the northwest. Critical consideration of both isotope systems leads to the conclusion that the Rb−Sr system of the GMG was disturbed by a later hydrothermal event. The ca. 326 Ma whole-rock Rb−Sr date for the BG is not in conflict with any of the K−Ar mineral dates and is taken as approaching the crystallization age of the Leuchtenberg granite. The K−Ar age progression within the northern lobe of the BG indicates that this part either cooled down over a protracted period of some 20 Ma or experienced reheating at ca. 300 Ma. The study highlights the potential of combined Rb−Sr and K−Ar dating in deciphering detailed chronology on the scale of a single igneous intrusion.


Biotite Granite Hydrothermal Event Igneous Intrusion Concordant Date Young Date 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


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  1. Abdullah N, Grauert B, Krohe A (1994) U−Pb- und Rb−Sr-Untersuchungen von Metagraniten der Mylonitzone von Floβ-Altenhammer und einer Probe des Leuchtenberger Granits (abstract). KTB-Rep 94-2:B37Google Scholar
  2. Beakhouse GP, McNutt RH, Krogh TE (1988) Comparative Rb−Sr and U−Pb zircon geochronology of late- to post-tectonic plutons in the Winnipeg River Belt, northwestern Ontario, Canada. Chem Geol 72:337–351Google Scholar
  3. Blümel P (1990) Variscan syn- and post-tectonic magmatism. In: Terranes in the circum-Atlantic paleozoic orogens. Int Conf Paleozoic Orogens Cent Eur, Göttingen-Giessen 1990, Field guide, Bohemian Massif, pp 37–47Google Scholar
  4. Bignell JD, Snelling NJ (1977) Geochronology of Malayan granites. Overseas Geol Miner Resour 47:1–71Google Scholar
  5. Brooks C, Hart SR, Wendt I (1972) Realistic use of two-error regression treatments as applied to Rb−Sr data. Rev Geophys Space Phys 10:551–557Google Scholar
  6. Bücker C, Soffel H (1986) Gravimetrie Oberpflaz (abstract). In: Althaus E, Emmermann R, Giese P (eds) Abstr Vol 2nd Colloq German Continental Deep-Drilling Project (KTB), Seeheim/Odenwald 1986, p 26Google Scholar
  7. Carl C, Dill H, Kreuzer H, Wendt I (1985) U/Pb- und K/Ar-Datierungen des Uranvorkommens Höhenstein/Oberpfalz. Geol Rundsch 743:483–504Google Scholar
  8. Chappell BW, White AJR (1974) Two contrasting granite types. Pacific Geol 8:173–174Google Scholar
  9. Criss RE, Lanphere MA, Taylor HP (1982) Effects of regional uplift, deformation, and meteoric-hydrothermal metamorphism on K−Ar ages of biotites in the southern half of the Idaho Batholith. J Geophys Res 87:7029–7046Google Scholar
  10. Darbyshire DPF, Shepherd TJ (1985) Chronology of granite magmatism and associated mineralization, SW England. J Geol Soc London 142:1159–1177Google Scholar
  11. Fischer G (1965) Über die modale Zusammensetzung der Eruptiva im ostbayerischen Kristallin. Geol Bavarica 55:7–33Google Scholar
  12. Fischer G, Schreyer W, Troll G, Voll G, Hart SR (1968) Hornblendealter aus dem ostbayerischen Grundgebirge. Neues Jahrb Mineral Monatsh 11:385–404Google Scholar
  13. Goebel T (1987): Geochemische und petrographische Untersuchungen and den Redwitziten von Wurz-Ilsenbach (unpublished). Dipl thesis Univ MunichGoogle Scholar
  14. Hammarstrom JM, Zen E-an (1986) Aluminium in hornblende: an empirical igneous geobarometer. Am Mineral 71:1297–1313Google Scholar
  15. Hammerschmidt K, Frank E (1991) Relics of high pressure metamorphism in the Lepontine Alps (Switzerland) — 40Ar/39Ar and microprobe analyses on white K-micas. Schweiz Mineral Petrogr Mitt 71:216–274Google Scholar
  16. Hansen BT, Teufel S, Ahrendt H (1989) Geochronology of the Moldanubian-Saxothuringian transition zone, Northeast Bavaria. In: Emmermann R, Wohlenberg J (eds) The German continental deep-drilling program (KTB), Springer, Berlin Heidelberg New York, pp 55–65Google Scholar
  17. Harre W, Kreuzer H, Lenz H, Müller P (1967) Zwischenbericht über K/Ar- und Rb/Sr-Datierungen von Gesteinen aus dem ostbayerisch-österreichischen Kristallin (unpublished). BfB Hannover, archive no. 25338 BGR report 5/67Google Scholar
  18. Hart SR (1964) The petrology and isotopic-mineral age relations of a contact zone in the Front Range, Colorado. J Geol 72:493–525Google Scholar
  19. Hess JC, Lippolt HJ, Gurbanov AG, Michalski I (1993) The cooling history of the late Pliocene Eldzhurtinskiy granite (Caucasus, Russia) and the thermochronological potential of grain-size/age relationships. Earth Planet Sci Lett 117:393–406Google Scholar
  20. Hölzl S, Köhler H (1994) Znkondatierungen am Leuchtenberger Granit, NE Bayern (abstract) KTB-Rep 94-2:B35Google Scholar
  21. Hofmann B (1992) Die metamorphe Geschichte des Kontakthofes Steinach und seiner Rahmengesteine. Ph D thesis Univ MunichGoogle Scholar
  22. Holl PK (1988) Isotopengeochemische Untersuchungen basischer und intermediärer Magmatite — Genese und Altersstellung redwitzitischer Gesteine Nordostbayerns. Ph D thesis Univ MunichGoogle Scholar
  23. Holl PK, von Drach V, Müller-Sohnius D, Köhler H (1989) Caledonian ages in Variscan rocks: Rb−Sr and Sm−Nd isotope variations in dioritic intrusives from the northwestern Bohemian Massif, West Germany. Tectonophysics 157:179–194Google Scholar
  24. Hradetzky H, Lippolt HJ (1993) Generation and distortion of Rb/Sr whole-rock isochrons-effects of metamorphism and alteration. Eur J Mineral 5:1175–1193Google Scholar
  25. Kleemann U (1991) Die P-T-t-d-Entwicklung im Grenzbereich zwischen der Zone von Erbendorf-Vohnenstrauss (ZEV) und dem Moldanubikum in der Oberpfalz/NE-Bayern. Ph D thesis Univ BochumGoogle Scholar
  26. Köhler, H (1970) Die Änderung der Zirkonmorphologie mit dem Differentiationsgrad eines Granits. Neues Jahrb Mineral Monatsh 1970:405–420Google Scholar
  27. Köhler H, Propach G, Troll G (1989) Exkursion zur Geologie, Petrographie und Geochronologie des NE-bayerischen Grundgebirges. Eur J Mineral Beih 1, 2:1–84Google Scholar
  28. Köhler H, Dodig D, Hölzl S (1993) Zirkondatierungen am Leuchtenberger Granit (NE Bayern). Eur J Mineral Beih 5, 1:116Google Scholar
  29. Köhler H, Müller-Sohnius D (1976) Ergänzende Rb−Sr Altersbestimmungen an Mineral- und Gesamtgesteinsproben des Leuchtenberger und des Flossenbürger Granits (NE Bayern). Neues Jahrb Mineral Monatsh 8:354–365Google Scholar
  30. Köhler H, Müller-Sohnius D, Cammann K (1974) Rb−Sr Altersbestimmungen an Mineral- und Gesamtgesteinsproben des Leuchtenberger und Flossenbürger Granits, NE Bayern. Neues Jahrb Mineral Abh 123, 1:63–85Google Scholar
  31. Kreuzer H, Seidel E, Schüssler U, Okrusch M, Lenz KL, Raschka H (1989) K−Ar geochronology of different tectonic units at the northwestern margin of the Bohemian Massif. Tectonophysics 157:149–178Google Scholar
  32. Kreuzer H, Henjes-Kunst F, Seidel E, Schüssler U, Bühn B (1993) Ar−Ar spectra on minerals from KTB and related medium-pressure units. KTB-Rep 93-2:133–136Google Scholar
  33. Krummenacher D, Gastil RG, Bushee J, Doupont J (1975) K−Ar apparent ages, Peninsular Ranges Batholith, Southern California and Baja California. Geol Soc Am Bull 86:760–768Google Scholar
  34. Kwan TS, Yap FL (1986) The pattern of K/Ar ages of biotites from the granites of Penang: its interpretation in the light of available Rb/Sr and U/Pb data. Geol Soc Malays Bull 19:281–289Google Scholar
  35. Kwan TS, Krähenbühl R, Jäger E (1992) Rb−Sr, K−Ar and fission track ages for granites from Penang Island, West Malaysia: an interpretation model for Rb−Sr whole-rock and for actual and experimental mica data. Contrib Mineral Petrol 111:527–542Google Scholar
  36. Leake BE (1978) Nomenclature of amphiboles. Mineral Mag 42:533–563Google Scholar
  37. Leake BE, Elias EM, Farrow CM (1988) The relationship of argon retentivity and chemical composition of hornblende. Geochim Cosmochim Acta 52:2165Google Scholar
  38. Madel J (1975) Geochemical structures in a multiple intrusion granite massif. Neues Jahrb Mineral Abh 124, 2:103–127Google Scholar
  39. Matheney RK, Brookins DG, Wallin ET, Shafiqullah M, Damon PE (1990) Incomplete reset Rb−Sr system from a Cambrian red-rock granophyre terrane, Florida Mountains, New Mexico, USA. Chem Geol 86:29–47Google Scholar
  40. McCarthy TS, Cawthorn RG (1980) Changes in initial 87Sr/86Sr ratio during protracted fractionation in igneous complexes. J Petrol 21:245–264Google Scholar
  41. Müller P (1979) Erlahrungen bei der Mineraltrennung für radiometrische Altersbestimmungen. Erzmetall 32, 5:232–236Google Scholar
  42. Müller P (1982) Von der CIPW-Norm ausgehende Berechnungen von Mineralbeständen magnmatischer Gesteine in Analogie zu der Modalzusammensetzung plutonischer und vulkanischer Gesteine. Geol Jahrb D 55:3–41Google Scholar
  43. Okrusch M (1969) Die Gneishornfelse um Steinach in der Oberpfalz. Contrib Mineral Petrol 22:32–72Google Scholar
  44. Okrusch M (1971) Garnet-cordierite-biotite equilibria in the Steinach aureole, Bavaria. Contrib Mineral Petrol 32:1–23Google Scholar
  45. O'Nions RK, Smith DGW, Baadsgaard H, Morton RD (1969) Influence of chemical composition on argon retentivity in metamorphic calcic amphiboles from south Norway. Earth Planet Sci Lett 5:339–345Google Scholar
  46. Onstott TC, Peacock MW (1987) Argon retentivity of hornblende: a field experiment in a slowly cooled metamorphic terrane. Geochim Cosmochim Acta 51:2891–2903Google Scholar
  47. Schleicher H, Lippolt HJ, Raczek I (1983) Rb−Sr systematics of Permian volcanites in the Schwarzwald (SW-Germany). II. Age of eruption and the mechanism of Rb−Sr whole-rock age distortions. Contrib Mineral Petrol 84:281–291Google Scholar
  48. Schüssler U (1990) Petrographie, Geochemie und Metamorphosealter von Metabasiten im KTB-Zielgebiet Oberpfalz. Geol Bavarica 95:5–99Google Scholar
  49. Schüssler U, Oppermann U, Kreuzer H, Seidel E, Okrusch M, Lenz KL, Raschka H (1986) Zur Altersstellung des ostbayerischen Kristallins-Ergebnisse neuer K−Ar-Datierungen. Geol Bavarica 89:21–47Google Scholar
  50. Siebel W (1993) Der Leuchtenberger Granit und seine assoziierten magmatischen Gesteine: zeitliche und stoffliche Entwicklungs-prozesse im Verlauf der Entstehung des Nordoberpfalz-Plutons. PhD thesis Univ HeidelbergGoogle Scholar
  51. Siebel W (1995) Constraints on Variscan granite emplacement in NE-Bavaria, Germany: further clues from an isotopic study of the Mitterteich granite. Geol Rundsch (in press)Google Scholar
  52. Siebel W, Höhndorf A, Wendt I (1995) Origin of Late Variscan granitoids of NE-Bavaria, Germany, evidenced by Nd isotope systematics. Chem Geol (in press)Google Scholar
  53. 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
  54. Stettner G (1992) Geologie im Umfeld der kontinentalen Tiefbohrung Oberpfalz. Bayer Geol Landesamt Munich: 1–240Google Scholar
  55. Stille P, Unruh DM, Tatsumoto M (1986) Pb, Sr, Nd, and Hf isotopic constraints on the origin of Hawaiian basalts and evidence for a unique mantle source. Geochim Cosmochim Acta 50:2303–2319Google Scholar
  56. Strunz H, Mücke A (1975) Die variskischen Granite der nördlichen Oberpfalz. Aufschluss Spec Iss 26:105–116Google Scholar
  57. Teufel S (1988) Vergleichende U−Pb- und Rb−Sr-Altersbestimmungen an Gesteinen des Übergangsbereiches Saxothuringikum/Moldanubikum, NE-Bayern. Göttinger Arb Geol Palaont 49:1–87Google Scholar
  58. Troll G (1968) Gliederung der redwitzitischen Gesteine Bayerns nach Stoff- und Gefügemerkmalen. I. Die Typlokalität von Marktredwitz in Oberfranken. Bayer Akad Wiss Abh 133:1–86Google Scholar
  59. Van Schmus WR, Bickford ME (1976) Rotation of Rb−Sr isochrons during low-grade events (abstract). IV Eur Coll Geochron Amsterdam: Abstr 93Google Scholar
  60. Villa IM, Puxeddu M (1994) Geochronology of the Larderello geothermal field: new data and the “closure temperature” issue. Contrib Mineral Petrol 115:415–426Google Scholar
  61. Voll G (1960) Stoff, Bau und Alter in der Grenzzone Moldanubikum/Saxothuringikum in Bayern unter besonderer Berücksichtigung gabbroider, amphibolitischer und kalksilikatführender Gesteine. Beih Geol Jahrb 42:1–182Google Scholar
  62. Von Blanckenburg F, Villa IM, Baur H, Morteani G, Steiger RH (1989) Time calibration of a PT-path from the Western Tauern Window, Eastern Alps: the problem of closure temperatures. Contrib Mineral Petrol 101:1–11Google Scholar
  63. Wanless RK, Stevens RD, Loveridge WD (1970) Anomalous parentdaughter isotopic relationships in rocks adjacent to the Grenville Front near Chibougamau, Quebec. Eclogae Geol Helv 63:345–364Google Scholar
  64. Wendt I,(1986) Radiometrische Methoden in der Geochronologie. Pilger Clausthaler Tektonische Hefte 23:1–170Google Scholar
  65. Wendt I, Lenz H, Harre W, Schoell M (1970) Total rock and mineral ages of granites from the Southern Schwarzwald, Germany. Eclogae Geol Helv 63:365–370Google Scholar
  66. Wendt I, Kreuzer H, Müller P, Schmid H (1986) Gesamtgesteins- und Mineraldatierungen des Falkenberger Granits. Geol Jahb E 34:5–66Google Scholar
  67. Wendt I, Höhndorf A, Kreuzer H, Müller P, Stettner G (1988) Gesamtgesteins- und Mineraldatierungen der Steinwaldgranite (NE-Bayern). Geol Jahrb E42:167–194Google Scholar
  68. Wendt I, Carl C, Kreuzer H, Müller P, Stettner G (1992) Ergänzende Messungen zum Friedenfelser Granit (Steinwald) und radiometrische Datierung der Ganggranite im Falkenberger Granit. Geol Jahrb A 137:3–24Google Scholar
  69. Sendt I, Ackermann H, Carl C, Kreuzer H, Müller P, Stettner G (1994) Rb/Sr-Gesamtgesteins- und K/Ar-Glimmerdatierungen der Granite von Flossenbürg und Bärnau. Geol Jahrb E51:3–29Google Scholar
  70. Willmann K (1920) Die Redwitzite, eine neue Gruppe von granitischen Lamprophyren. Z Dtsch Geol Ges 71:1–33Google Scholar
  71. Wright AE, Bowes DR (1979) Geochemistry of the appinite suite. In: Harris AL, Holland CH, Leake BE (eds) The Caledonides of the British Isles-reviewed. Geol Soc London, pp 699–704Google Scholar

Copyright information

© Springer-Verlag 1995

Authors and Affiliations

  • Wolfgang Siebel
    • 1
  1. 1.GeoForschungsZentrum PotsdamPotsdamGermany

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