Trace element composition of rutile and the application of Zr-in-rutile thermometry to UHT metamorphism (Epupa Complex, NW Namibia)

Meyer, Melanie; John, Timm; Brandt, Sönke; Klemd, Reiner

doi:10.1016/j.lithos.2011.07.013

Cited by 67 publications

(48 citation statements)

References 46 publications

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“…9a) that are also recorded by other (independent) means such as silicate mineral assemblages, ternary feldspar thermometry and/or Al-in-orthopyroxene thermometry (e.g. Baldwin and Brown, 2008;Racek et al, 2008;Luvizotto and Zack, 2009;Kotková and Harley, 2010;Meyer et al, 2011;Ague and Eckert, 2012;Blackburn et al, 2012;Kooijman et al, 2012;Ague et al, 2013;Ewing et al, 2013;. Additional benefits of Zr-in-rutile thermometry include:…”

Section: Trace Element Thermometrymentioning

confidence: 99%

“…granulite facies, including UHT) is not because Zr diffusion in and out of rutile is sluggishdthey argue it is efficientdbut rather due to rutile being or becoming chemically isolated from an external Zr reservoir, namely zircon, during cooling. Very large inter-grain ranges of Zr contents in rutile at the thin section scale (Racek et al, 2008;Luvizotto and Zack, 2009;Meyer et al, 2011;Kooijman et al, 2012; can be correlated with proximity to zircon (Luvizotto and Zack, 2009;Kooijman et al, 2012;Ewing et al, 2013), including zircon that grew from expulsion of Zr from rutile, with rutile in immediate proximity to zircon recording lower Zr-in-rutile temperatures than rutile grains (chemically) isolated from zircon (Taylor-Jones and Powell, 2015). Placing the Zr content of rutile in the context of chemical communication with the external Zr (and Si) reservoir zircondi.e.…”

Section: Trace Element Thermometrymentioning

confidence: 99%

See 1 more Smart Citation

On ultrahigh temperature crustal metamorphism: Phase equilibria, trace element thermometry, bulk composition, heat sources, timescales and tectonic settings

Kelsey

Hand

2015

Geoscience Frontiers

377

285

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a b s t r a c tUltrahigh temperature (UHT) metamorphism is the most thermally extreme form of regional crustal metamorphism, with temperatures exceeding 900 C. UHT crustal metamorphism is recognised in more than 50 localities globally in the metamorphic rock record and is accepted as 'normal' in the spectrum of regional crustal processes. UHT metamorphism is typically identified on the basis of diagnostic mineral assemblages such as sapphirine þ quartz, orthopyroxene þ sillimanite AE quartz and osumilite in MgeAlrich rock compositions, now usually coupled with pseudosection-based thermobarometry using internally-consistent thermodynamic data sets and/or Al-in-Orthopyroxene and ternary feldspar thermobarometry. Significant progress in the understanding of regional UHT metamorphism in recent years includes: (1) development of a ferric iron activityecomposition thermodynamic model for sapphirine, allowing phase diagram calculations for oxidised rock compositions; (2) quantification of UHT conditions via trace element thermometry, with Zr-in-rutile more commonly recording higher temperatures than Ti-in-zircon. Rutile is likely to be stable at peak UHT conditions whereas zircon may only grow as UHT rocks are cooling. In addition, the extent to which Zr diffuses out of rutile is controlled by chemical communication with zircon; (3) more fully recognising and utilising temperature-dependent thermal properties of the crust, and the possible range of heat sources causing metamorphism in geodynamic modelling studies; (4) recognising that crust partially melted either in a previous event or earlier in a long-duration event has greater capacity than fertile, unmelted crust to achieve UHT conditions due to the heat energy consumed by partial melting reactions; (5) more strongly linking UePb geochronological data from zircon and monazite to PeT points or path segments through using Y þ REE partitioning between accessory and major phases, as well as phase diagrams incorporating Zr and REE; and (6) improved insight into the settings and factors responsible for UHT metamorphism via geodynamic forward models. These models suggest that regional UHT metamorphism is, principally, geodynamically related to subduction, coupled with elevated crustal radiogenic heat generation rates.Ó 2014, China University of Geosciences (Beijing) and Peking University. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/ licenses/by-nc-nd/4.0/).

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Section: Trace Element Thermometrymentioning

confidence: 99%

Section: Trace Element Thermometrymentioning

confidence: 99%

On ultrahigh temperature crustal metamorphism: Phase equilibria, trace element thermometry, bulk composition, heat sources, timescales and tectonic settings

Kelsey

Hand

2015

Geoscience Frontiers

377

285

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“…Subchondritic Nb/Ta ratios occur in rutile from both medium to high-grade metamorphic regions (e.g. Meyer et al 2011;Ewing et al 2013) and HP metamorphic regions (Xiao et al 2006;John et al 2011;Huang et al 2012). Rutile compositions mostly display subchondritic Nb/Ta values (chondritic value 19.9, Münker et al 2003) with a range of 11-19 and Zr/Hf values (chondritic value 34.3 ±0.3, Münker et al 2003) range between 20 and 33 (Fig.…”

Section: şEkilmentioning

confidence: 99%

Kazdağ Masifi’nde (Biga Yarımadası) Yer Alan Meta-Ofiyolitik Kayaların TitaniQ Termometresi ve Rutil İz Element Bileşimi

Şengün¹

2016

Türkiye Jeoloji Bülteni / Geological Bulletin of Turkey

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ÖZOfiyolitik meta-gabrolar Biga Yarımadası'nın güneyinde Kazdağ Masifi'nde yüzlek vermektedir. Metagabrolar içerisindeki rutil ve kuvars minerallerinin iz element bileşimleri LA-ICP-MS ile saptanmıştır. Hem matriks içerisinde hem de granat içerisinde kapanım olarak bulunan rutil tanelerinin Zr içeriği 176 ile 428 ppm arasında değişmekte ve ortalama Zr içeriği ise 335 ppmdir. Rutil taneleri genellikle homojen Zr dağılımına sahiptir. Kazdağ Masifi'nde incelenen örnekler içerisindeki rutil taneleri subkondritik Nb/Ta (11-23) ve Zr/Hf (20-33) değerleriyle karakterize olmaktadır. Nb/Ta ve Zr/Hf pozitif korelasyon göstermekte ve bu da muhtemelen silikat parçalanmasından kaynaklanmaktadır. Nb/Ta ve Zr/Hf oranları Ta ve Hf içeriklerindeki azalmayla artma eğilimi sunmaktadır. Rutil tanelerinin çekirdekleri genellikle düşük Nb/Ta (17-18) oranlarıyla karakterize olurken kenar kesimleri göreceli olarak daha yüksek Nb/ Ta (19-23) oranlarına sahiptir. Rutilin iz element analizleri rutil kristallerinin metamorfik akışkanlardan itibaren geliştiğini göstermektedir.Kuvarsın Ti içeriği rutilin Zr içeriğine göre geliştirilen termometreyle birlikte kullanıldığında kuvars ve rutilin birlikte bulunduğu kayalarda basınç-sıcaklık hesabı yapılabilmektedir. Ofiyolitik meta-gabroların basınç-sıcaklık koşulları kuvarsın Ti içeriğine ve rutilin Zr içeriğine göre hesaplanmıştır. Kuvarsın Ti içeriği 28 ile 42 ppm arasında değişmekte ve ortalama 36 ppmdir. Basınç-sıcaklık diyagramında kuvarsın Ti eş değer eğrileri ile rutilin Zr eş değer eğrileri çakıştırıldığında elde edilen sıcaklık değeri ~ 660 o C, basınç değeri ise ~ 10 kbardır. Meta-ofiyolitik kayaların basınç-sıcaklık koşulları bu kayaların Kazdağ Masifi içerisinde daha yüksek basınçlı ayrı bir tektonik dilim olduğunu ifade etmektedir. Amfibolit fasiyesi metamorfizması Neo-Tetis okyanusunun İzmir-Ankara kolunun kuzeye doğru Sakarya Zonu altına dalmasından kaynaklanmaktadır. Metamorfizmanın hemen ardından Kazdağ Masifi'nin ortayüksek dereceli metamorfik kayaları kendi içerisinde çarpışma sırasında güneye doğru sıkışmayla birbiri üzerine bindirmiştir.

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“…The high pressure, post peak UHT-IBC evolution inferred for Mt Charles suggests a prolonged residence time at HP-HT conditions in the lower crust, perhaps linked to the removal of a heat source through lateral flow in (e.g. Chardon et al, 2009;2011), or the long-lived presence of a heat-flow buffer e.g. partial melt (Clark et al, 2011;Stuwe, 1995).…”

Section: Recent Phase Equilibrium Modelling Of Sapphirine-bearing Assmentioning

confidence: 99%

Zr-in-rutile resetting in aluminosilicate bearing ultra-high temperature granulites: Refining the record of cooling and hydration in the Napier Complex, Antarctica

Mitchell

Harley

2017

Lithos

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Zr-in-rutile resetting in aluminosilicate ultra-high temperature granulites: refining the record of cooling and hydration in the Napier Complex, Antarctica Ruairidh J. Mitchell, Simon L. Harley PII:S0024-4937(16)30425-X Please cite this article as: Mitchell, Ruairidh J., Harley, Simon L., Zr-in-rutile resetting in aluminosilicate ultra-high temperature granulites: refining the record of cooling and hydration in the Napier Complex, Antarctica, LITHOS (2016), ABSTRACTThe relative validity and closure temperature of the Zr-in-rutile thermometer for recording UHT metamorphism is process dependent and hotly debated. We present an integrated petrological approach to Zrin-rutile thermometry including phase equilibrium (pseudoseciton) modelling in complex chemical systems with updated mineral a-X models and systematic in-situ microanalysis of rutile. This study is centred on highpressure rutile bearing UHT granulites from Mt Charles, Napier Complex, Antarctica. P-T phase equilibrium modelling of two garnet bearing granulites (samples 49677, 49701) constrains an overall post-peak near isobaric cooling (IBC) evolution for the Napier Complex at Mt Charles; from ~14kbar, 1100 o C with moderate decompression to ~11kbar, 800-900 o C. Local hydration on cooling over this temperature range is recorded in a kyanite bearing granulite (sample 49688) with an inferred injection of aqueous fluid equivalent to up to 9 mol% H 2 O from T-MH 2 O modelling. Further late stage cooling to <740 o C is recorded by voluminous retrograde mica growth and partial preservation of a ky-pl-kfs-bt-liq bearing equilibrium assemblage. Overall, Zr-in-rutile temperatures at 11kbar (Tomkins et al., 2007) are reset to between 606 o C and 780 o C across all samples, with flat core-rim Zr concentration profiles in all rutiles. However, zircon precipitates as inclusions, needle exsolutions, or rods along rutile grain boundaries are recrystallised from rutiles in qz/fsp domains. Reintegrating the Zr-in-rutile concentration 'lost' via the recrystallization of these zircon precipitates (e.g. Pape et al., 2016) can recover maximum concentrations of up to ~2.2wt% and thus maximum peak temperatures of ~1149 o C at 11kbar. Rutile Nb-Ta signatures and rounded rutile grains without zircon precipitates in hydrated mica domains in sample 49688 provides evidence for fluid-mediated mobility of Zr and Nb during retrograde cooling in hydrated lithologies. Aqueous fluid supplemented excess H 2 O liberated by melt crystallisation, interacting with rutile on cooling of sample 49688 to reset Zr-in-rutile temperatures (606-780 o C) at the Mt Charles locality. The wide range of geochemical and petrological characteristics ofNapier Complex rutile highlights that Zr-in-rutile reintegration and a broad petrological approach is required for successful interpretation of Zr-in-rutile geothermometry for long-lived regional UHT metamorphism.

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Trace element composition of rutile and the application of Zr-in-rutile thermometry to UHT metamorphism (Epupa Complex, NW Namibia)

Cited by 67 publications

References 46 publications

On ultrahigh temperature crustal metamorphism: Phase equilibria, trace element thermometry, bulk composition, heat sources, timescales and tectonic settings

On ultrahigh temperature crustal metamorphism: Phase equilibria, trace element thermometry, bulk composition, heat sources, timescales and tectonic settings

Kazdağ Masifi’nde (Biga Yarımadası) Yer Alan Meta-Ofiyolitik Kayaların TitaniQ Termometresi ve Rutil İz Element Bileşimi

Zr-in-rutile resetting in aluminosilicate bearing ultra-high temperature granulites: Refining the record of cooling and hydration in the Napier Complex, Antarctica

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