Hostname: page-component-586b7cd67f-t7czq Total loading time: 0 Render date: 2024-11-29T01:02:37.577Z Has data issue: false hasContentIssue false
  • English
  • Français

Dating of zircon and monazite from diamondiferous quartzofeldspathic rocks of the Saxonian Erzgebirge – hints at burial and exhumation velocities

Published online by Cambridge University Press:  05 July 2018

H.-J. Massonne ,
A. Kennedy ,
L. Nasdala  and
T. Theye
H.-J. Massonne*
Affiliation:
Institut für Mineralogie und Kristallchemie, Universität Stuttgart, Azenbergstr. 18, D-70174 Stuttgart, Germany
A. Kennedy
Affiliation:
Department of Applied Physics, Curtin University of Technology, Kent St. Bentley WA, 6102, Australia
L. Nasdala
Affiliation:
Institut für Mineralogie und Kristallographie, Universität Wien, Althanstr. 14, A-1090 Vienna, Austria
T. Theye
Affiliation:
Institut für Mineralogie und Kristallchemie, Universität Stuttgart, Azenbergstr. 18, D-70174 Stuttgart, Germany
*
E-mail: [email protected]
Get access Rights & Permissions [Opens in a new window]

Abstract

In order to better understand the formation and evolution processes of ultrahigh pressure (UHP) felsic rocks, we determined the ages of various domains of zircon and monazite crystals from the diamondiferous quartzofeldspathic rocks of the Saxonian Erzgebirge. According to cathodoluminescence imagery and Th/U ratios, three zircon zones were distinguished. Each was dated using several spot analyses from a sensitive high-resolution ion microprobe analysing Pb, U and Th isotopes. The results were: (1) core zone – 21 analyses: Th/U ≤ 40.023 and 337.0±2.7 Ma (2σ, combined 206Pb/238U-207Pb/235U age); (2) diamond-bearing intermediate zone – 23 analyses: Th/U ≥ 50.037 and 336.8±2.8 Ma; and (3) rim zone – 12 analyses: Th/U = 0.015–0.038 (plus one analysis of 0.164) and 330.2±5.8 Ma. The U-Pb obtained ages are virtually concordant. Furthermore, two oscillatory zoned zircon cores (Th/U ≥ 50.8) yielded (~concordant) ages of ~400 Ma. Six SHRIMP analyses of monazites gave an age of 332.4±2.1 Ma. In addition, Pb, Th and U contents in monazite were analysed with an electron microprobe (EMP). A mean age of 324.7±8.0 (2σ) Ma was acquired from 113 analyses.

By combining the defined ages with previously published P-T conditions, minimum velocities for burial and exhumation were estimated. In addition, we present a likely geodynamic scenario involving age data from the literature as well as this study: beginning 340 million years ago, gneisses at the base of a thickened continentalcrust (~1.8 GPa, 650ºC) were transported to depths of at least 130 km, possibly as deep as 250 km. Here they were heated (>1050ºC) and partially melted and as a result began to rise rapidly. The burial and subsequent ascent back to a depth of 50 km, where zircon rims and monazite formed, took only a few million years and perhaps significantly less.

Keywords

zirconmonazitegeochronologySHRIMPEMPSaxonian ErzgebirgeVariscanultrahigh pressure metamorphismexhumation
Type
Research Article
Information
Mineralogical Magazine , Volume 71 , Issue 4 , August 2007 , pp. 407 - 425
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2007

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Brätz, H. (2000) Radiometrische Altersdatierung und geochemische Untersuchungen von Orthogneisen, Graniten und Granitporphyren aus dem Ruhlaer Kristallin, Mitteldeutsche Kristallinzone. PhD thesis, Universität Würzburg, Germany, 151 pp.Google Scholar
Breitkreuz, C. and Kennedy, A.K. (1999) Magmatic flare–up at the Carboniferous/Permian boundary in the NE German Basin revealed by SHRIMP zircon ages. Tectonophysics, 302, 307–326.CrossRefGoogle Scholar
Chopin, C. (2003) Ultrahigh pressure metamorphism: tracing continentalcrust into the mantle. Earth and Planetary Science Letters, 212, 1–14.CrossRefGoogle Scholar
Claoue–Long, J.C., Sobolev, N.V., Shatsky, V.S. and Sobolev, A.V. (1991) Zircon response to diamondpressure metamorphism in the Kokchetav massif. Geology, 19, 710–713.2.3.CO;2>CrossRefGoogle Scholar
Compston, W., Williams, I.S. and Meyer, C. (1984) UPb geochronology of zircons from lunar breccia 73217 using a sensitive high mass–resolution ion microprobe. Proceedings of the 14th LPSC, Part 2, Journal of Geophysical Research, 89B, 525–534.Google Scholar
Connelly, J.N. (2000) Degree of preservation of igneous zonation in zircon as a signpost for concordancy in U/Pb geochronology. Chemical Geology, 172, 25–39.Google Scholar
De Laeter, J.R. and Kennedy, A.K. (1998) A double focusing mass spectrometer for geochronology. International Journal of Mass Spectrometry and Ion Processes, 178, 43–50.Google Scholar
Dombrowski, A., Henjes–Kunst, F., Höhndorf, A., Kröner, A., Okrusch, M. and Richter, P. (1995) Orthogneisses in the Spessart Crystalline Complex, northwest Bavaria: witnesses of Silurian granitoid magmatism at an active continentalmargin. Geologische Rundschau, 84, 399–411.CrossRefGoogle Scholar
Düffels, K. and Massonne, H.–J. (2001) Geochemical signatures of diamondiferous gneisses and their adjacent rocks from the Erzgebirge, Germany. Terra Nostra, 5, 24–26.Google Scholar
Gebauer, D., Schertl, H.–P., Brix, M. and Schreyer, W. (1997) 35 Ma old ultrahigh–pressure metamorphism and evidence for very rapid exhumation in the Dora Maira Massif, Western Alps. Lithos, 41, 5–24.CrossRefGoogle Scholar
Grasemann, B., Ratschbacher, L. and Hacker, B.R. (1998) Exhumation of ultrahigh–pressure rocks: thermalboundary conditions and cooling history. Pp. 117–139 in: When Continents Collide: Geodynamics and Geochemistry of Ultrahigh–pressure Rocks (Hacker, B.R. and Liou, J.G., editors). Kluwer Academic Publishers, Dordrecht, The Netherlands.Google Scholar
Hermann, J., Rubatto, D., Korsakov, A. and Shatsky, V.S. (2001) Multiple zircon growth during fast exhumation of diamondiferous, deeply subducted continentalcrust (Kokchetav Massif, Kazakhstan). Contributions to Mineralogy and Petrology, 141, 66–82.CrossRefGoogle Scholar
Jercinovic, M.J. and Williams, M.L. (2005) Analytical perils (and progress) in electron microprobe trace element analysis applied to geochronology: background acquisition interferences, and beam irradiation effects. American Mineralogist, 90, 526–546.CrossRefGoogle Scholar
Katayama, I., Zayachkovsky, A.A. and Maruyama, S. (2000) Prograde pressure–temperature records from inclusions in zircons from ultrahigh–pressure–highpressure rocks of the Kokchetav Massif, northern Kazakhstan. The Island Arc, 9, 417–427.CrossRefGoogle Scholar
Kennedy, A.K. (2000) The search for new zircon standards for SIMS. Pp. 109–111 in: Beyond 2000: New Frontiers in Isotope Geoscience, L orne, Abstracts and Proceedings (Woodhead, J.D., Hergt, J.M. and Noble, W.P., editors).Google Scholar
Keppler, H. and Wyllie, P.J. (1990) Role of fluids in transport and fractionation of uranium and thorium in magmatic processes. Nature, 348, 531–533.CrossRefGoogle Scholar
Kröner, A. and Willner, A.P. (1998) Time of formation and peak of Variscan HP–HT metamorphism of quartz–feldspar rocks in the central Erzgebirge, Saxony, Germany. Contributions to Mineralogy and Petrology, 132, 1–20.Google Scholar
Ludwig, K.R. (1999) Isoplot/Ex, version 2.06: A geochronological tool–kit for Microsoft Excel. Special Publication 1a, Berkeley Geochronology Center, 1–49.Google Scholar
Massonne, H.–J. (2001) First find of coesite in the ultrahigh–pressure metamorphic region of the Central Erzgebirge, Germany. European Journal of Mineralogy, 13, 565–570.CrossRefGoogle Scholar
Massonne, H.–J. (2003) A comparison of the evolution of diamondiferous quartz–rich rocks from the Saxonian Erzgebirge and the Kokchetav Massif: are so–called diamondiferous gneisses magmatic rocks? Earth and Planetary Science Letters, 216, 345–362.CrossRefGoogle Scholar
Massonne, H.–J. (2005) Involvement of crustal material in delamination of the lithosphere after continentcontinent collision. International Geology Review, 47, 792–804.CrossRefGoogle Scholar
Massonne, H.–J. and Nasdala, L. (2003) Characterization of an early metamorphic stage through inclusions in zircon of a diamondiferous quartzofeldspathic rock from the Erzgebirge, Germany. American Mineralogist, 88, 883–889.CrossRefGoogle Scholar
Massonne, H.–J. and O’Brien, P.J. (2003) The Bohemian Massif and the NW Himalaya. Pp. 145–187 in: Ultrahigh Pressure Metamorphism (Carswell, D.A. and Compagnoni, R., editors). EMU Notes in Mineralogy, 5.Google Scholar
Massonne, H.–J. and Neuser, R. (2005) Ilmenite exsolution in olivine from the serpentinite body at Zöblitz, Saxonian Erzgebirge. Mineralogical Magazine, 69, 119–124.CrossRefGoogle Scholar
Massonne, H.–J., Bernhardt, H.J., Dettmar, D., Kessler, E., Medenbach, O. and Westphal, T. (1998) Simple identification and quantification of microdiamonds in rock thin–sections. European Journal of Mineralogy, 10, 497–504.CrossRefGoogle Scholar
Massonne, H.–J., Nasdala, L. and Kennedy, A. (2001) UTh– Pb dating of zircons and monazites from diamondiferous gneisses of the Saxonian Erzgebirge–implications for their UHP/HP evolution. 6th International Eclogite Conference, Niihama, Japan, Abstract Volume, 88.Google Scholar
Massonne, H.–J., Willner, A.P. and Gerya, T.V. (2007) Densities of metapelitic rocks at high to ultrahigh pressure conditions: what are the geodynamic consequences? Earth and Planetary Science Letters, 256, 12–27.CrossRefGoogle Scholar
Nasdala, L. and Massonne, H.–J. (2000) Microdiamonds from the Saxonian Erzgebirge, Germany: in situ micro–Raman characterisation. European Journal of Mineralogy, 12, 495–498.CrossRefGoogle Scholar
Nasdala, L., Gruner, T., Nemchin, A.A., Pidgeon, R.T. and Tichomirowa, M. (1996) New SHRIMP ion microprobe measurements on zircons from Saxonian magmatic and metamorphic rocks. Freiberger Isotopenkolloquium, Proceedings, 205–214.Google Scholar
O’Brien, P.J. and Sachan, H.K. (2000) Diffusion modelling in garnet from Tso Morari eclogite and implications for exhumation models. Earth Science Frontiers, 7, 25–27.Google Scholar
Ota, T., Terabayashi, M., Parkinson, C.D. and Masago, H. (2000) Thermobaric structure of the Kokchetav ultrahigh–pressure–high–pressure massif deduced from a north–south transect in the Kulet and Saldat– Kolregions, northern Kazakhstan. The Island Arc, 9, 328–357.CrossRefGoogle Scholar
Patin˜o Douce, A.E. and McCarthy, T.C. (1998) Melting of crustal rocks during continental collision and subduction. Pp. 27–55 in: When Continents Collide: Geodynamics and Geochemistry of Ultrahigh–pressure Rocks (Hacker, B.R. and Liou, J.G., editors). Kluwer Academic Publishers, Dordrecht, The Netherlands.Google Scholar
Pyle, J.M., Spear, F.S., Wark, D.A., Daniel, C.G. and Storm, L.C. (2005) Contributions to precision and accuracy of chemicalages of monazite. American Mineralogist, 90, 547–577.CrossRefGoogle Scholar
Reed, S.J.B. and Buckley, A. (1998) Rare–earth element determination in minerals by electron–probe microanalysis: application of spectrum synthesis. Mineralogical Magazine, 62, 1–8.CrossRefGoogle Scholar
Romer, R.L. and Rötzler, J. (2001) P–T–t evolution of ultrahigh–temperature granulites from the Saxon Granulite Massif, Germany. Part II: Geochronology. Journal of Petrology, 42, 2015–2032.CrossRefGoogle Scholar
Rubatto, D. and Hermann, J. (2001) Exhumation as fast as subduction? Geology, 29, 3–6.2.0.CO;2>CrossRefGoogle Scholar
Rubatto, D., Williams, I.S. and Buick, I.S. (2001) Zircon and monazite response to prograde metamorphism in the Reynolds Range, central Australia. Contributions to Mineralogy and Petrology, 140, 458–468.CrossRefGoogle Scholar
Schaltegger, U., Fanning, C.M., Günther, D., Maurin, J.C., Schulmann, K. and Gebauer, D. (1999) Growth, annealing and recrystallization of zircon and preservation of monazite in high–grade metamorphism: conventionaland in–situ U–Pb isotope, cathodoluminescence and microchemical evidence. Contributions to Mineralogy and Petrology, 134, 186–201.CrossRefGoogle Scholar
Scherrer, N.C., Engi, M., Gnos, E., Jakob, V. and Liechti, A. (2000) Monazite analysis; from sample preparation to microprobe age dating and REE quantification. Schweizerische Mineralogische und Petrographische Mitteilungen, 80, 93–105.Google Scholar
Seydoux–Guillaume, A.–M., Paquette, J.–L., Wiedenbeck, M., Montel, J.–M. and Heinrich W. (2002) Experimentalresetting of the U–Th–Pb systems in monazite. Chemical Geology, 191, 165–181.CrossRefGoogle Scholar
Shatsky, V.S., Sobolev, N.V. and Vavilow, M.A. (1995) Diamond–bearing metamorphic rocks of the Kokchetav Massif (Northern Kazakhstan). Pp. 427–455 in: Ultrahigh Pressure Metamorphism (Coleman, R. and Wang, X., editors). Cambridge University Press, Cambridge, MA, USA.Google Scholar
Steiger, R.H. and Jäger, E. (1977) Subcommission on geochronology: convention on the use of decay constants in geo– and cosmochronology. Earth and Planetary Science Letters, 46, 359–362.Google Scholar
Stöckhert, B., Duyster, J., Trepmann, C. and Massonne H.–J. (2001) Microdiamond daughter crystals precipitated from supercriticalCO H silicate fluids included in garnet, Erzgebirge, Germany. Geology, 29, 391–394.2.0.CO;2>CrossRefGoogle Scholar
Tichomirowa, M., Berger, H.–J., Koch, E.A., Belyatski, B.V., Goetze, J., Kempe, U., Nasdala, L. and Schaltegger, U. (2001) Zircon ages of high–grade gneisses in the Eastern Erzgebirge (CentralEuropean Variscides) – constraints on origin of the rocks and Precambrian to Ordovician magmatic events in the Variscan foldbelt. Lithos, 56, 303–332.CrossRefGoogle Scholar
Tichomirowa, M., Whitehouse, M.J. and Nasdala, L. (2005) Resorption, growth, solid state recrystallisation, and annealing of granulite facies zircon – a case study from the CentralErzgebirge, Bohemian Massif. Lithos, 82, 25–50.CrossRefGoogle Scholar
Werner, O. and Reich, S. (1997) 40Ar/39Ar–Abkühlalter von Gesteinen mit unterschiedlicher P–TEntwicklung aus dem Schiefermantel des Sächsischen Granulitgebirges. Terra Nostra, 97/5, 196–198.Google Scholar
Werner, O. and Lippolt, H.J. (2000) White mica 40Ar/39Ar ages of Erzgebirge metamorphic rocks: simulating the chronological results by a model of Variscan crustalim brication. Pp. 323–336 in: Orogenic Processes: Quantification and Modelling in the Variscan Belt (Franke, W., Haak, V., Oncken, O. and Tanner, D., editors). SpecialPubl ication, 179. Geological Society, London.Google Scholar
Willner, A.P., Rötzler, K. and Maresch, W.V. (1997) Pressure–temperature and fluid evolution of quartzofeldspathic metamorphic rocks with a relic highpressure, granulite–facies history from the Central Erzgebirge (Saxony, Germany). Journal of Petrology, 38, 307–336.CrossRefGoogle Scholar
Willner, A.P., Krohe, A. and Maresch, W.V. (2000) Interrelated P–T–t–d paths in the Variscan Erzgebirge dome (Saxony, Germany): Constraints on the rapid exhumation of high–pressure rocks from the root zone of a collisional orogen. International Geology Review, 42, 64–85.Google Scholar