Dating high-grade metamorphism—constraints from rare-earth elements in zircon and garnet

Whitehouse, Martin J.; Platt, J. P.

doi:10.1007/s00410-002-0432-z

Cited by 457 publications

(266 citation statements)

References 36 publications

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“…Harley et al (2001) and Harley (2002) and interpreted to reflect HT UHT REE equilibrium between zircon and garnet. They are also consistent with D values obtained by Whitehouse and Platt (2003) for zircon interpreted to have grown in the presence of garnet. In the specific case of this leucosome, the marked change in the distribution of REE, particularly HREE, between zircon and garnet must reflect either a change in the minerals with which the zircon was growing or being modified and/or a change in the physical and chemical conditions attending zircon formation.…”

Section: Discussionsupporting

confidence: 90%

“…Recent studies have proposed equilibrium REE D zircon/garnet values that are consistent and near unity for MREE, but different by as much as an order of magnitude for HREE. Rubatto (2002) proposed that HREE are more favorably incorporated into zircon than garnet, whereas Harley et al (2001) and Whitehouse and Platt (2003) suggested that the equilibrium REE D zircon/garnet values for HREE are less than unity ( Yb D zircon/garnet ≈ 0.7), indicating that the HREE are preferred in garnet over zircon for the pelite garnet compositions and high temperature conditions considered in their studies.…”

Section: Introductionmentioning

confidence: 98%

“…Zircon trace element geochemistry has recently been used to investigate the processes or conditions of zircon crystallization. Application of rare earth element (REE) partitioning between zircon and garnet has been applied to interpret the event significance of zircon ages (Harley et al, 2001;Harley, 2002;Rubatto, 2002;Whitehouse and Platt, 2003). Both zircon and garnet favour heavy rare earth elements (HREEs) relative to light to middle rare earth elements (L MREEs).…”

Section: Introductionmentioning

confidence: 99%

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Zircon growth in UHT leucosome: constraints from zircon-garnet rare earth elements (REE) relations in Napier Complex, East Antarctica

Hokada

Harley

2004

Journal of Mineralogical and Petrological Sciences

125

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Feldspathic leucosomes occur in an ultrahigh temperature (UHT) metamorphosed garnet bearing paragneiss/ quartzite in the Napier Complex, East Antarctica. Coarse (200 400 μ m) zircon grains occurring in the leucosomes display 3 textural domains: (I) dark CL (cathodoluminescence) structured inner core, (II) bright CL structured outer core, and (III) dark CL structureless rim. Chemical compositions, especially chondrite normalized REE patterns obtained by SIMS analysis, correlate with these three domains: the inner core (domain I) shows HREE enrichment with Yb(n)/Gd(n) = 3.3, whereas the outer core (II) and rim (III) have flat to relatively depleted HREE patterns with Yb(n)/Gd(n) = 0.7 0.8. Th/U ratios decrease from 3.2 in the zircon inner core (I) to 1.2 in outer core (II) and to 0.3 in the rim (III).Garnets near such zircon grains display two trace element compositional features. Firstly, high core Zr contents (300 ppm) decrease to 100 ppm within 50 100 μ m of grain rims. Secondly, the HREE distribution between zircon inner core (I) and garnet core is 2 at Gd ( . This marked change in the HREE distribution between zircon and garnet must reflect either a change in the minerals with which the zircon was growing or being modified, a change in the physical and chemical conditions of zircon growth, or a combination of the two. Based on comparisons with recent estimates of equilibrium zircon/garnet HREE distribution coefficients we infer that the inner core (I) did not grow with the garnet that occurs in the paragneiss but grew within a garnet absent melt that was then injected into the gneiss. The resulting leucosome then underwent wall rock reaction with the enclosing garnet bearing gneiss, causing a decrease in garnet to Zr contents to values approaching equilibrium with melt, and precipitating the zircon outer core (II). Finally, the zircon rim (III) and later monazite formed in a HREE depleted environment. Melt injection, reaction and crystallization of the leucosomes took place within the time interval 2496 2471 Ma at the end of the UHT history of the Napier Complex.

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Section: Discussionsupporting

confidence: 90%

Section: Introductionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

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Zircon growth in UHT leucosome: constraints from zircon-garnet rare earth elements (REE) relations in Napier Complex, East Antarctica

Hokada

Harley

2004

Journal of Mineralogical and Petrological Sciences

125

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“…Zeck et al 1989;Platt et al 2013). Conversely, schist, migmatites and mylonitic gneisses are preCarboniferous and represent a polymetamorphic basement affected by at least the Variscan and Alpine orogenies (Montel et al 2000;Whitehouse and Platt 2003;Rossetti et al 2010;Massonne 2014). Rocks from all levels in the crustal section seem to record nearly isothermal decompression paths, from 1.4-1.2 kbar to 0.6-0.4 GPa at 750-850 ºC in the case of the mylonitic gneisses located at the contact with the Ronda peridotites (Torres-Roldán 1981;Argles et al 1999;Platt et al 2003;Barich et al 2014).…”

Section: Geological Settingmentioning

confidence: 99%

The composition of nanogranitoids in migmatites overlying the Ronda peridotites (Betic Cordillera, S Spain): the anatectic history of a polymetamorphic basement

Acosta-Vigil

Barich

Bartoli

et al. 2016

Contrib Mineral Petrol

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The study of the composition of primary melts during anatexis of high-pressure granulitic migmatites is relevant to understand the generation and differentiation of continental crust.Peritectic minerals in migmatites can trap dropless of melt that forms via incongruent melting reactions during crustal anatexis. These melt inclusions commonly crystallize and form nanogranitoids upon slow cooling of the anatectic terrane. To obtain the primary compositions of crustal melts recorded in these nanogranitoids, including volatile concentrations and information on fluid regimes, they must be remelted and rehomogenize before analysis. A new occurrence of nanogranitoids was recently reported in garnets of mylonitic metapelitic gneisses (former high pressure granulitic migmatites) at the bottom of the prograde metamorphic sequence of Jubrique, located on top of the Ronda peridotite slab (Betic Cordillera, S Spain). Nanogranitoids within separated chips of cores and rims of large garnets from these former migmatites were remelted at 15 kbar and 850, 825 or 800 ºC and dry (without added H 2 O), during 24 hours, using a piston cylinder apparatus. Although all experiments show glass (former melt) within melt inclusions, the extent of rehomogenization depends on the experimental temperature. Experiments at 850-825 ºC show abundant disequilibrium microstructures, whereas those at 800 ºC show a relatively high proportion of rehomogenized nanogranitoids, indicating that anatexis and entrapment of melt inclusions in these rocks was likely close to 800 ºC. Electron microprobe and NanoSIMS analyses show that experimental glasses are leucogranitoid and peraluminous, though define two distinct compositional groups. Type I corresponds to K-rich, Ca-and H 2 O-poor leucogranitic melts, whereas type II represents K-poor, Ca-and H 2 O-rich granodioritic to tonalitic melts. Type I and II melt inclusions are found in most cases at the cores and rims of large garnets, respectively. We tentatively suggest that these former migmatites underwent two melting events under contrasting fluid regimes, possibly during two different orogenic periods. This 3 study demonstrates the strong potential of melt inclusions studies in migmatites and granulites in order to unravel their anatectic history, particularly in strongly deformed rocks where most of the classical anatectic microstructures have been erased during deformation.

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“…Magmatic zircons are enriched in heavy REE (HREE) compared to light REE (LREE), with steep-rising REE patterns, and show a distinctive positive Ce anomaly as well as negative Eu anomalies. By contrast, metamorphic zircons show marked depletion of HREE, characterized by flat MREE-HREE patterns without negative Eu or Ce anomaly (Maas et al, 1992;Belousova et al, 1998Belousova et al, , 2002Hoskin and Ireland, 2000;Rubatto, 2002;Corfu et al, 2003;Hoskin and Schaltegger, 2003;Whitehouse and Platt, 2003;Yao et al, 2011;Ma et al, 2012b).…”

Section: Zircon U-pb Dating Resultsmentioning

confidence: 94%

Geological characteristics and age of the Dahongliutan Fe-ore deposit in the Western Kunlun orogenic belt, Xinjiang, northwestern China

Wang

Huang

et al. 2016

Journal of Asian Earth Sciences

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Dating high-grade metamorphism—constraints from rare-earth elements in zircon and garnet

Cited by 457 publications

References 36 publications

Zircon growth in UHT leucosome: constraints from zircon-garnet rare earth elements (REE) relations in Napier Complex, East Antarctica

Zircon growth in UHT leucosome: constraints from zircon-garnet rare earth elements (REE) relations in Napier Complex, East Antarctica

The composition of nanogranitoids in migmatites overlying the Ronda peridotites (Betic Cordillera, S Spain): the anatectic history of a polymetamorphic basement

Geological characteristics and age of the Dahongliutan Fe-ore deposit in the Western Kunlun orogenic belt, Xinjiang, northwestern China

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