An improved understanding of Zr-in-rutile thermometry in application to ultrahigh temperature metamorphic rocks
This item is only available electronically. Zirconium in rutile (ZIR) concentrations were analysed in samples from two localities in ultrahigh temperature (UHT: >900°C) metamorphic terranes: Anakapalle, Eastern Ghats Province, India (~1030 °C), and Ayatollah Island, Napier Complex, Antarctica (~1...
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ftunivadelaidedl:oai:digital.library.adelaide.edu.au:2440/120938 2023-05-15T13:51:55+02:00 An improved understanding of Zr-in-rutile thermometry in application to ultrahigh temperature metamorphic rocks Gaehl, A. School of Physical Sciences Anakapalle, Eastern Ghats Province, India; Ayatollah Island, Napier Complex, Antarctica 2016 application/pdf http://hdl.handle.net/2440/120938 en eng http://hdl.handle.net/2440/120938 Keywords: Honours Geology zirconium in rutile trace element thermometry UHT Eastern Ghats Napier Complex pseudosection Thesis 2016 ftunivadelaidedl 2023-02-05T19:37:22Z This item is only available electronically. Zirconium in rutile (ZIR) concentrations were analysed in samples from two localities in ultrahigh temperature (UHT: >900°C) metamorphic terranes: Anakapalle, Eastern Ghats Province, India (~1030 °C), and Ayatollah Island, Napier Complex, Antarctica (~1050 °C). ZIR temperatures from analyses of these rocks were categorised according to their microstructural setting—inclusion versus grain boundary—and distance from xenocrystic zircon. ZIR temperatures from three of four samples were all or mostly well below UHT conditions—up to 400 °C in some cases. However, upon reintegrating exsolved zirconium back into rutile grains the distribution of ZIR temperatures in all samples becomes bimodal, more typical of the global UHT ZIR thermometry dataset. There is no obvious trend in the ZIR concentration or temperature data relating to the proximity of rutile to xenocrystic zircon, or to the microstructural setting of rutile, suggesting that rutile and zircon (and quartz) communicate over sufficiently long length scales during the prograde and retrograde history. Stunted Si diffusion does not appear to have been a dominant factor in determining ZIR concentrations and temperatures (contrast with Taylor-Jones & Powell, 2015), as there are no known examples of rutile grains preserving peak (i.e. >1000 °C) temperatures that have not exsolved zircon. The major consequence is that ZIR thermometry may almost never preserve the peak UHT conditions in regional terranes where cooling is prolonged. The bimodal ZIR concentration and temperature distribution may relate to a subtle, undetected microstructural control on access to Si and Zr reservoirs combined with different timing of growth of different rutile grains. Thesis (B.Sc.(Hons)) -- University of Adelaide, School of Physical Sciences, 2016 Thesis Antarc* Antarctica The University of Adelaide: Digital Library Napier ENVELOPE(-58.440,-58.440,-62.167,-62.167) |
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Open Polar |
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The University of Adelaide: Digital Library |
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ftunivadelaidedl |
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English |
topic |
Keywords: Honours Geology zirconium in rutile trace element thermometry UHT Eastern Ghats Napier Complex pseudosection |
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Keywords: Honours Geology zirconium in rutile trace element thermometry UHT Eastern Ghats Napier Complex pseudosection Gaehl, A. An improved understanding of Zr-in-rutile thermometry in application to ultrahigh temperature metamorphic rocks |
topic_facet |
Keywords: Honours Geology zirconium in rutile trace element thermometry UHT Eastern Ghats Napier Complex pseudosection |
description |
This item is only available electronically. Zirconium in rutile (ZIR) concentrations were analysed in samples from two localities in ultrahigh temperature (UHT: >900°C) metamorphic terranes: Anakapalle, Eastern Ghats Province, India (~1030 °C), and Ayatollah Island, Napier Complex, Antarctica (~1050 °C). ZIR temperatures from analyses of these rocks were categorised according to their microstructural setting—inclusion versus grain boundary—and distance from xenocrystic zircon. ZIR temperatures from three of four samples were all or mostly well below UHT conditions—up to 400 °C in some cases. However, upon reintegrating exsolved zirconium back into rutile grains the distribution of ZIR temperatures in all samples becomes bimodal, more typical of the global UHT ZIR thermometry dataset. There is no obvious trend in the ZIR concentration or temperature data relating to the proximity of rutile to xenocrystic zircon, or to the microstructural setting of rutile, suggesting that rutile and zircon (and quartz) communicate over sufficiently long length scales during the prograde and retrograde history. Stunted Si diffusion does not appear to have been a dominant factor in determining ZIR concentrations and temperatures (contrast with Taylor-Jones & Powell, 2015), as there are no known examples of rutile grains preserving peak (i.e. >1000 °C) temperatures that have not exsolved zircon. The major consequence is that ZIR thermometry may almost never preserve the peak UHT conditions in regional terranes where cooling is prolonged. The bimodal ZIR concentration and temperature distribution may relate to a subtle, undetected microstructural control on access to Si and Zr reservoirs combined with different timing of growth of different rutile grains. Thesis (B.Sc.(Hons)) -- University of Adelaide, School of Physical Sciences, 2016 |
author2 |
School of Physical Sciences |
format |
Thesis |
author |
Gaehl, A. |
author_facet |
Gaehl, A. |
author_sort |
Gaehl, A. |
title |
An improved understanding of Zr-in-rutile thermometry in application to ultrahigh temperature metamorphic rocks |
title_short |
An improved understanding of Zr-in-rutile thermometry in application to ultrahigh temperature metamorphic rocks |
title_full |
An improved understanding of Zr-in-rutile thermometry in application to ultrahigh temperature metamorphic rocks |
title_fullStr |
An improved understanding of Zr-in-rutile thermometry in application to ultrahigh temperature metamorphic rocks |
title_full_unstemmed |
An improved understanding of Zr-in-rutile thermometry in application to ultrahigh temperature metamorphic rocks |
title_sort |
improved understanding of zr-in-rutile thermometry in application to ultrahigh temperature metamorphic rocks |
publishDate |
2016 |
url |
http://hdl.handle.net/2440/120938 |
op_coverage |
Anakapalle, Eastern Ghats Province, India; Ayatollah Island, Napier Complex, Antarctica |
long_lat |
ENVELOPE(-58.440,-58.440,-62.167,-62.167) |
geographic |
Napier |
geographic_facet |
Napier |
genre |
Antarc* Antarctica |
genre_facet |
Antarc* Antarctica |
op_relation |
http://hdl.handle.net/2440/120938 |
_version_ |
1766255949944717312 |