Exsolution of dolomite and application of calcite–dolomite solvus geothermometry in high‐grade marbles: an example from Skallevikshalsen, East Antarctica
Abstract Calcite–dolomite solvus geothermometry is a versatile method for the estimation of metamorphic temperature because of its simplicity. However, in medium‐ to high‐grade metamorphic rocks the accuracy of estimating temperature by the integration of unmixed dolomite and calcite is hampered by...
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crwiley:10.1111/j.1525-1314.2010.00877.x 2024-09-15T17:40:46+00:00 Exsolution of dolomite and application of calcite–dolomite solvus geothermometry in high‐grade marbles: an example from Skallevikshalsen, East Antarctica MIZUOCHI, H. SATISH‐KUMAR, M. MOTOYOSHI, Y. MICHIBAYASHI, K. 2010 http://dx.doi.org/10.1111/j.1525-1314.2010.00877.x https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1525-1314.2010.00877.x https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1525-1314.2010.00877.x en eng Wiley http://onlinelibrary.wiley.com/termsAndConditions#vor Journal of Metamorphic Geology volume 28, issue 5, page 509-526 ISSN 0263-4929 1525-1314 journal-article 2010 crwiley https://doi.org/10.1111/j.1525-1314.2010.00877.x 2024-08-01T04:20:44Z Abstract Calcite–dolomite solvus geothermometry is a versatile method for the estimation of metamorphic temperature because of its simplicity. However, in medium‐ to high‐grade metamorphic rocks the accuracy of estimating temperature by the integration of unmixed dolomite and calcite is hampered by the heterogeneous distribution of unmixed dolomite, difficulties in distinguishing between preexisting and exsolved dolomite and demarcating grain boundaries. In this study, it is shown that calcite–dolomite solvus thermometry can be applied to calcite inclusions in forsterite and spinel for the estimation of peak metamorphic temperature in granulite facies marbles from Skallevikshalsen, East Antarctica. The marbles are comprised of a granoblastic mineral assemblage of calcite + dolomite + forsterite + diopside + spinel + phlogopite ± apatite, characteristic of granulite facies metamorphic conditions. Forsterite, spinel and apatite frequently contain ‘negative crystal’ inclusions of carbonates that display homogeneously distributed dolomite lamellae. On the basis of narrow ranges of temperature (850–870 °C) recorded from carbonate inclusions compared with the range from matrix carbonate it is regarded that the inclusion carbonates represent a closed system. Furthermore, this estimate is consistent with dolomite–graphite carbon isotope geothermometry, and is considered to be the best estimate of peak metamorphic temperature for this region. Matrix calcite records different stages of retrograde metamorphism and re‐equilibration of calcite that continued until Mg diffusion ceased at ∼ 460 °C. Electron backscattered diffraction (EBSD) results together with morphological features of unmixed coarse tabular dolomite suggest anisotropic diffusion and mineral growth are influenced by crystallographic orientation. Identification of sub‐grain boundaries and formation of fine‐grained unmixing in calcite rims suggest the presence of grain boundary fluids in the late retrograde stages of metamorphic evolution. These results, thus, ... Article in Journal/Newspaper Antarc* Antarctica East Antarctica Wiley Online Library Journal of Metamorphic Geology 28 5 509 526 |
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Wiley Online Library |
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English |
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Abstract Calcite–dolomite solvus geothermometry is a versatile method for the estimation of metamorphic temperature because of its simplicity. However, in medium‐ to high‐grade metamorphic rocks the accuracy of estimating temperature by the integration of unmixed dolomite and calcite is hampered by the heterogeneous distribution of unmixed dolomite, difficulties in distinguishing between preexisting and exsolved dolomite and demarcating grain boundaries. In this study, it is shown that calcite–dolomite solvus thermometry can be applied to calcite inclusions in forsterite and spinel for the estimation of peak metamorphic temperature in granulite facies marbles from Skallevikshalsen, East Antarctica. The marbles are comprised of a granoblastic mineral assemblage of calcite + dolomite + forsterite + diopside + spinel + phlogopite ± apatite, characteristic of granulite facies metamorphic conditions. Forsterite, spinel and apatite frequently contain ‘negative crystal’ inclusions of carbonates that display homogeneously distributed dolomite lamellae. On the basis of narrow ranges of temperature (850–870 °C) recorded from carbonate inclusions compared with the range from matrix carbonate it is regarded that the inclusion carbonates represent a closed system. Furthermore, this estimate is consistent with dolomite–graphite carbon isotope geothermometry, and is considered to be the best estimate of peak metamorphic temperature for this region. Matrix calcite records different stages of retrograde metamorphism and re‐equilibration of calcite that continued until Mg diffusion ceased at ∼ 460 °C. Electron backscattered diffraction (EBSD) results together with morphological features of unmixed coarse tabular dolomite suggest anisotropic diffusion and mineral growth are influenced by crystallographic orientation. Identification of sub‐grain boundaries and formation of fine‐grained unmixing in calcite rims suggest the presence of grain boundary fluids in the late retrograde stages of metamorphic evolution. These results, thus, ... |
format |
Article in Journal/Newspaper |
author |
MIZUOCHI, H. SATISH‐KUMAR, M. MOTOYOSHI, Y. MICHIBAYASHI, K. |
spellingShingle |
MIZUOCHI, H. SATISH‐KUMAR, M. MOTOYOSHI, Y. MICHIBAYASHI, K. Exsolution of dolomite and application of calcite–dolomite solvus geothermometry in high‐grade marbles: an example from Skallevikshalsen, East Antarctica |
author_facet |
MIZUOCHI, H. SATISH‐KUMAR, M. MOTOYOSHI, Y. MICHIBAYASHI, K. |
author_sort |
MIZUOCHI, H. |
title |
Exsolution of dolomite and application of calcite–dolomite solvus geothermometry in high‐grade marbles: an example from Skallevikshalsen, East Antarctica |
title_short |
Exsolution of dolomite and application of calcite–dolomite solvus geothermometry in high‐grade marbles: an example from Skallevikshalsen, East Antarctica |
title_full |
Exsolution of dolomite and application of calcite–dolomite solvus geothermometry in high‐grade marbles: an example from Skallevikshalsen, East Antarctica |
title_fullStr |
Exsolution of dolomite and application of calcite–dolomite solvus geothermometry in high‐grade marbles: an example from Skallevikshalsen, East Antarctica |
title_full_unstemmed |
Exsolution of dolomite and application of calcite–dolomite solvus geothermometry in high‐grade marbles: an example from Skallevikshalsen, East Antarctica |
title_sort |
exsolution of dolomite and application of calcite–dolomite solvus geothermometry in high‐grade marbles: an example from skallevikshalsen, east antarctica |
publisher |
Wiley |
publishDate |
2010 |
url |
http://dx.doi.org/10.1111/j.1525-1314.2010.00877.x https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1525-1314.2010.00877.x https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1525-1314.2010.00877.x |
genre |
Antarc* Antarctica East Antarctica |
genre_facet |
Antarc* Antarctica East Antarctica |
op_source |
Journal of Metamorphic Geology volume 28, issue 5, page 509-526 ISSN 0263-4929 1525-1314 |
op_rights |
http://onlinelibrary.wiley.com/termsAndConditions#vor |
op_doi |
https://doi.org/10.1111/j.1525-1314.2010.00877.x |
container_title |
Journal of Metamorphic Geology |
container_volume |
28 |
container_issue |
5 |
container_start_page |
509 |
op_container_end_page |
526 |
_version_ |
1810486791416840192 |