Multiple zircon growth and recrystallization during polyphase Late Carboniferous to Triassic metamorphism in granulites of the Ivrea Zone (Southern Alps): an ion microprobe (SHRIMP) study

Vavra, G.; Gebauer, D.; Schmid, R.; Compston, W.

doi:10.1007/s004100050132

Cited by 692 publications

(363 citation statements)

References 39 publications

Supporting

Mentioning

327

Contrasting

Unclassified

Order By: Relevance

“…Zircons separated from metagranodiorite (type-1) by this study show featureless rims with bright luminescence that cut across primary oscillatory zones and metamorphic zircons showing ''ghost zoning'' (Hoskin & Black, 2000). All these features are interpreted to represent crystallization of rims and recrystallization of magmatic zircon domains under high-grade thermal events (Corfu, Hanchar, Hoskin, and Kinny, 2003;Hoskin & Black, 2000;Pidgeon, 1992;Vavra, Gebauer, & Schmid, 1996;Vavra et al, 1999;Wu & Zheng, 2004). The analyses obtained from these metamorphic domains yield ages of 584 ± 8 Ma (sample 05-2), 582 ± 9 (sample 371), 589 ± 14 Ma (sample 05-3/ 1) and (Tables B and C).…”

Section: Interpretation Of Age Datamentioning

confidence: 64%

Late Neoproterozoic granulite facies metamorphism in the Menderes Massif, Western Anatolia/Turkey: implication for the assembly of Gondwana

Koralay

2015

Geodinamica Acta

View full text Add to dashboard Cite

The Menderes Massif is a major polymetamorphic complex in Western Turkey. The late Neoproterozoic basement consists of partially migmatized paragneisses and metapelites in association with orthogneiss intrusions. Pelitic granulite, paragneiss and orthopyroxene-bearing orthogneiss (charnockite) of the basement series form the main granulite-facies lithologies. Charnockitic metagranodiorite and metatonalite are magnesian in composition and show calc-alkalic to alkali-calcic affinities. Nd and Sr isotope systematics indicate homogeneous crustal contamination. The zircons in charnockites contain featureless overgrowth and rim textures representing metamorphic growth on magmatic cores and inherited grains. Charnockites yield crytallization age of~590 Ma for protoliths and they record granulite-facies overprint at~580 Ma. These data indicate that the Menderes Massif records late Neoproterozoic magmatic and granulite-facies metamorphic events. Furthermore, the basement rocks have been overprinted by Eocene Barrovian-type Alpine metamorphism at~42 Ma. The geochronological data and inferred latest Neoproterozoic-early Cambrian palaeogeographic setting for the Menderes Massif to the north of present-day Arabia indicate that the granulite-facies metamorphism in the Menderes Massif can be attributed to the Kuunga Orogen (600-500 Ma) causing the final amalgamation processes for northern part of the Gondwana.

show abstract

Section: Interpretation Of Age Datamentioning

confidence: 64%

Late Neoproterozoic granulite facies metamorphism in the Menderes Massif, Western Anatolia/Turkey: implication for the assembly of Gondwana

Koralay

2015

Geodinamica Acta

View full text Add to dashboard Cite

show abstract

“…dark-CL emission (U-rich), uniform in CL-appearance or sector zoned (e.g. Vavra et al 1996Vavra et al , 1999Schaltegger et al 1999;Rubatto and Gebauer 2000;Corfu et al 2003). This rim type is the most abundant and occurs in amphibolite facies samples as well as samples of restite or melanosome at granulite facies.…”

Section: Zircon Texturesmentioning

confidence: 98%

Zircon ages in granulite facies rocks: decoupling from geochemistry above 850 °C?

Kunz

Regis

Engi

2018

Contrib Mineral Petrol

View full text Add to dashboard Cite

Granulite facies rocks frequently show a large spread in their zircon ages, the interpretation of which raises questions: Has the isotopic system been disturbed? By what process(es) and conditions did the alteration occur? Can the dates be regarded as real ages, reflecting several growth episodes? Furthermore, under some circumstances of (ultra-)high-temperature metamorphism, decoupling of zircon U-Pb dates from their trace element geochemistry has been reported. Understanding these processes is crucial to help interpret such dates in the context of the P-T history. Our study presents evidence for decoupling in zircon from the highest grade metapelites (> 850 °C) taken along a continuous high-temperature metamorphic field gradient in the Ivrea Zone (NW Italy). These rocks represent a well-characterised segment of Permian lower continental crust with a protracted high-temperature history. Cathodoluminescence images reveal that zircons in the mid-amphibolite facies preserve mainly detrital cores with narrow overgrowths. In the upper amphibolite and granulite facies, preserved detrital cores decrease and metamorphic zircon increases in quantity. Across all samples we document a sequence of four rim generations based on textures. U-Pb dates, Th/U ratios and Ti-in-zircon concentrations show an essentially continuous evolution with increasing metamorphic grade, except in the samples from the granulite facies, which display significant scatter in age and chemistry. We associate the observed decoupling of zircon systematics in high-grade non-metamict zircon with disturbance processes related to differences in behaviour of non-formula elements (i.e. Pb, Th, U, Ti) at high-temperature conditions, notably differences in compatibility within the crystal structure.

show abstract

“…4a, b). A magmatic origin is attributed to the cores, whereas the rims are typical of zircon growth during high-grade metamorphism (Vavra et al, 1996). Sample L1415 is a Uivak I grey tonalitic orthogneiss from Dog Island.…”

Section: Samplesmentioning

confidence: 99%

Peak to post-peak thermal history of the Saglek Block of Labrador: A multiphase and multi-instrumental approach to geochronology

et al. 2018

View full text Add to dashboard Cite

A B S T R A C TThe Saglek Block of coastal Labrador forms the western margin of the North Atlantic Craton, where Archean gneisses and granulites have been reworked during the Paleoproterozoic. Previous work has established that the block is a composite of Eoarchean to Mesoarchean protoliths metamorphosed to upper amphibolite and granulite facies at around 2.8-2.7 Ga. New in-situ microbeam dating of accessory minerals in granoblastic gneisses reveals a complex peak to post-peak thermal history. Zircon growth at ca. 3.7-3.6 Ga provides the age of formation of the tonalitic protoliths to the gneisses. Further zircon growth in syn-tectonic granitic gneiss and monazite growth in a variety of orthogneisses confirm peak metamorphic conditions at ca. 2.7 Ga, but also reveal high-temperature conditions at ca. 2.6 Ga and 2.5 Ga. The former is interpreted as the waning stages of the 2.7 Ga granulite event, whereas the latter is associated with a younger phase of granitic magmatism. In addition, apatite ages of ca. 2.2 Ga may represent either cooling associated with the 2.5 Ga event or a previously unrecognized greenschist-facies metamorphism event that predates the Torngat Orogeny.

show abstract

Multiple zircon growth and recrystallization during polyphase Late Carboniferous to Triassic metamorphism in granulites of the Ivrea Zone (Southern Alps): an ion microprobe (SHRIMP) study

Cited by 692 publications

References 39 publications

Late Neoproterozoic granulite facies metamorphism in the Menderes Massif, Western Anatolia/Turkey: implication for the assembly of Gondwana

Late Neoproterozoic granulite facies metamorphism in the Menderes Massif, Western Anatolia/Turkey: implication for the assembly of Gondwana

Zircon ages in granulite facies rocks: decoupling from geochemistry above 850 °C?

Peak to post-peak thermal history of the Saglek Block of Labrador: A multiphase and multi-instrumental approach to geochronology

Contact Info

Product

Resources

About