Javascript är avstängt eller blockerat i din webbläsare. Detta kan leda till att vissa delar av vår webbplats inte fungerar som de ska. Sätt på javascript för optimal funktionalitet och utseende.

Webbläsaren som du använder stöds inte av denna webbplats. Alla versioner av Internet Explorer stöds inte längre, av oss eller Microsoft (läs mer här: * https://www.microsoft.com/en-us/microsoft-365/windows/end-of-ie-support).

Var god och använd en modern webbläsare för att ta del av denna webbplats, som t.ex. nyaste versioner av Edge, Chrome, Firefox eller Safari osv.

Lotta_2018-10

Charlotte Möller

Professor

Lotta_2018-10

Metamorphic zircon formation at the transition from gabbro to eclogite in Trollheimen-Surnadalen, Norwegian Caledonides

Författare

  • Victoria Beckman
  • Charlotte Möller
  • Ulf Söderlund
  • Fernando Corfu
  • Jan Pallon
  • Kevin R. Chamberlain

Summary, in English

A transition from gabbro to eclogite has been investigated at Vinddoldalen in south-central Norway, with the aim to link reaction textures to metamorphic zircon growth and to obtain a direct U-Pb zircon age of the metamorphic process. In the different rocks of the transition zone zircon occurs as (I) igneous prismatic grains, (II) metamorphic polycrystalline rims and pseudomorphs after baddeleyite, and (III) as tiny (< 10 mu m) bead-like zircon grains. Textural relations suggest that type II zircon formed by breakdown of baddeleyite in the presence of silica, whereas Fe-Ti oxides were the main Zr source for the type III zircon. Subsolidus liberation of Zr and formation of bead zircon took place by oxyexsolution of titanomagnetite during fluid-assisted metamorphism, and by resorption of Fe-Ti oxide in rock domains that were completely recrystallized to eclogite. SIMS (secondary ion mass spectrometry) and TIMS (thermal ionization mass spectrometry) dating provides comparable U-Pb ages of magmatic zircon and baddeleyite. Baddeleyite (TIMS) yielded an age of 1457 +/- 11 Ma for the gabbro emplacement. Bead-type metamorphic zircon from eclogite gave 425 +/- 10 Ma (TIMS) dating the metamorphic transition from gabbro to eclogite in the upper basement of the Lower Allochthon in the south-central Scandinavian Caledonides.

Avdelning/ar

  • Berggrundsgeologi
  • Kärnfysik

Publiceringsår

2014

Språk

Engelska

Sidor

403-424

Publikation/Tidskrift/Serie

Geological Society Special Publication

Volym

390

Dokumenttyp

Artikel i tidskrift

Förlag

Geological Society of London

Ämne

  • Geology
  • Subatomic Physics

Status

Published

ISBN/ISSN/Övrigt

  • ISSN: 2041-4927