|
| << vorige | volgende >> |
Tijdschrift beschrijving
Alle jaargangen van het bijbehorende tijdschrift
Alle afleveringen van het bijbehorende jaargang
Alle artikelen van de bijbehorende aflevering
Details van artikel 7 van 13 gevonden artikelen
| Titel: |
Geochronological evidence for ∼ 530-550 Ma juxtaposition of two Proterozoic metamorphic terranes in the Musgrave Ranges, Central Australia |
| Auteur: |
Maboko, M. A. H. McDougall, I. Zeitler, P. K. Williams, I. S. |
| Verschenen in: |
Australian journal of earth sciences |
| Paginering: | Jaargang 39 (1992) nr. 4 pagina's 457-471 |
| Jaar: |
1992-09 |
| Inhoud: |
Contrasting temperature-time paths from two Proterozoic metamorphic belts in the Musgrave Ranges, central Australia suggest that they represent district tectonothermal terranes. The thermal histories of these terranes converged about 530-550 Ma ago, as they were juxtaposed along the Woodroffe Thrust. Amphibolite fades metamorphism in the gneissic terrane north of the thrust is dated by zircon U-Pb ages at ∼ 1600 Ma. Subsequently, the gneiss was intruded by granitoid at ∼ 1500 Ma, followed by a second metamorphic event which may be dated by a few zircon ages at ∼ 1400 Ma. Age maxima of ∼ 1300 Ma and ∼ 1260 Ma from steadily rising 40Ar-39Ar spectra date cooling below closure temperatures of hornblende and K-feldspar respectively, following the latter metamorphism. In contrast, zircon U-Pb ages date granulite facies metamorphism in the terrane south of the Woodroffe Thrust at ∼ 1200 Ma. Post-metamorphic cooling in the granulite terrane was slow with hornblende and biotite remaining open to argon diffusion until after ∼ 930 and ∼ 690 Ma respectively. The thermal histories of the two terranes converged ∼ 530-550 Ma ago, when metamorphism associated with burial of the gneiss under an overriding ∼ 15 km thick thrust sheet of granulite led to the growth of syn-tectonic muscovite in both terranes and caused near total resetting of 40Ar-39Ar ages in pre-existing biotite and K-feldspar in the gneiss. Cooling from this event was slow with the gneiss dropping below temperatures of ∼ 260° C at ∼ 350 Ma and the granulite cooling below ∼ 200°C at ∼ 400 Ma. |
| Uitgever: |
Taylor & Francis |
| Bronbestand: |
Elektronische Wetenschappelijke Tijdschriften |
Details van artikel 7 van 13 gevonden artikelen
| << vorige | volgende >> |