The impact of the Pan-African-aged tectonothermal event on high-grade rocks at Mount Brown, East Antarctica
This study presents monazite and rutile U–Pb and hornblende and biotite 40Ar/39Ar geochronological data for high-grade rocks of the eastern Grenville-aged Rayner orogen at Mount Brown in order to analyse the extent and degree of Pan-African-aged reworking. Monazite from paragneiss yields U–Pb ages o...
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ftanucanberra:oai:openresearch-repository.anu.edu.au:1885/259038 2024-01-14T09:59:33+01:00 The impact of the Pan-African-aged tectonothermal event on high-grade rocks at Mount Brown, East Antarctica Liu, Xiaochun Fu, Bin Li, Qiuli Zhao, Yue Liu, Jian Chen, Hong application/pdf http://hdl.handle.net/1885/259038 https://doi.org/10.1017/S0954102019000518 https://openresearch-repository.anu.edu.au/bitstream/1885/259038/3/01_Liu_The_impact_of_the_2020.pdf.jpg en_AU eng British Antarctic Survey 0954-1020 http://hdl.handle.net/1885/259038 doi:10.1017/S0954102019000518 https://openresearch-repository.anu.edu.au/bitstream/1885/259038/3/01_Liu_The_impact_of_the_2020.pdf.jpg © Antarctic Science Ltd 2020. http://creativecommons.org/licenses/by/4.0/ Creative Commons Attribution licence Antarctic Science hornblende/biotite 40Ar/39Ar dating isotopic resetting monazite/rutile U–Pb dating Journal article ftanucanberra https://doi.org/10.1017/S0954102019000518 2023-12-15T09:32:58Z This study presents monazite and rutile U–Pb and hornblende and biotite 40Ar/39Ar geochronological data for high-grade rocks of the eastern Grenville-aged Rayner orogen at Mount Brown in order to analyse the extent and degree of Pan-African-aged reworking. Monazite from paragneiss yields U–Pb ages of 910 Ma for larger granular grains and 670–630 Ma for smaller globular beads around garnet porphyroblasts or hosted by symplectites. Rutile from leucogneiss yields U–Pb ages of 520–515 Ma. Hornblende and biotite from different rock types yield 40Ar/39Ar plateau ages of 744 and 520–505 Ma, respectively. Combining these results with published zircon U–Pb age data suggests that granulite facies metamorphism occurred at 910 Ma, with a local low-temperature fluid flow event at 670–630 Ma and thermal reworking at 520–505 Ma. The older age of 744 Ma may reflect cooling or partial resetting of the hornblende 40Ar/39Ar system, indicating that Pan-African-aged reworking did not exceed temperatures much higher than the hornblende Ar closure temperature. These data also suggest that the complete isotopic resetting of some minerals may occur without the growth of new mineral phases, providing an example of the style of reworking that is likely to occur in polymetamorphic terranes. This research was supported by the National Natural Science Foundation of China (No. 41530209), Central Public-Interest Scientific Institution Basal Research Fund (No. JYYWF201819) and Geological Investigation Project of the Chinese Geological Survey (No. DD20190579). Article in Journal/Newspaper Antarc* Antarctic Science Antarctica East Antarctica Australian National University: ANU Digital Collections East Antarctica Rayner ENVELOPE(-45.166,-45.166,-60.650,-60.650) Mount Brown ENVELOPE(86.000,86.000,-68.617,-68.617) Antarctic Science 32 1 45 57 |
institution |
Open Polar |
collection |
Australian National University: ANU Digital Collections |
op_collection_id |
ftanucanberra |
language |
English |
topic |
hornblende/biotite 40Ar/39Ar dating isotopic resetting monazite/rutile U–Pb dating |
spellingShingle |
hornblende/biotite 40Ar/39Ar dating isotopic resetting monazite/rutile U–Pb dating Liu, Xiaochun Fu, Bin Li, Qiuli Zhao, Yue Liu, Jian Chen, Hong The impact of the Pan-African-aged tectonothermal event on high-grade rocks at Mount Brown, East Antarctica |
topic_facet |
hornblende/biotite 40Ar/39Ar dating isotopic resetting monazite/rutile U–Pb dating |
description |
This study presents monazite and rutile U–Pb and hornblende and biotite 40Ar/39Ar geochronological data for high-grade rocks of the eastern Grenville-aged Rayner orogen at Mount Brown in order to analyse the extent and degree of Pan-African-aged reworking. Monazite from paragneiss yields U–Pb ages of 910 Ma for larger granular grains and 670–630 Ma for smaller globular beads around garnet porphyroblasts or hosted by symplectites. Rutile from leucogneiss yields U–Pb ages of 520–515 Ma. Hornblende and biotite from different rock types yield 40Ar/39Ar plateau ages of 744 and 520–505 Ma, respectively. Combining these results with published zircon U–Pb age data suggests that granulite facies metamorphism occurred at 910 Ma, with a local low-temperature fluid flow event at 670–630 Ma and thermal reworking at 520–505 Ma. The older age of 744 Ma may reflect cooling or partial resetting of the hornblende 40Ar/39Ar system, indicating that Pan-African-aged reworking did not exceed temperatures much higher than the hornblende Ar closure temperature. These data also suggest that the complete isotopic resetting of some minerals may occur without the growth of new mineral phases, providing an example of the style of reworking that is likely to occur in polymetamorphic terranes. This research was supported by the National Natural Science Foundation of China (No. 41530209), Central Public-Interest Scientific Institution Basal Research Fund (No. JYYWF201819) and Geological Investigation Project of the Chinese Geological Survey (No. DD20190579). |
format |
Article in Journal/Newspaper |
author |
Liu, Xiaochun Fu, Bin Li, Qiuli Zhao, Yue Liu, Jian Chen, Hong |
author_facet |
Liu, Xiaochun Fu, Bin Li, Qiuli Zhao, Yue Liu, Jian Chen, Hong |
author_sort |
Liu, Xiaochun |
title |
The impact of the Pan-African-aged tectonothermal event on high-grade rocks at Mount Brown, East Antarctica |
title_short |
The impact of the Pan-African-aged tectonothermal event on high-grade rocks at Mount Brown, East Antarctica |
title_full |
The impact of the Pan-African-aged tectonothermal event on high-grade rocks at Mount Brown, East Antarctica |
title_fullStr |
The impact of the Pan-African-aged tectonothermal event on high-grade rocks at Mount Brown, East Antarctica |
title_full_unstemmed |
The impact of the Pan-African-aged tectonothermal event on high-grade rocks at Mount Brown, East Antarctica |
title_sort |
impact of the pan-african-aged tectonothermal event on high-grade rocks at mount brown, east antarctica |
publisher |
British Antarctic Survey |
url |
http://hdl.handle.net/1885/259038 https://doi.org/10.1017/S0954102019000518 https://openresearch-repository.anu.edu.au/bitstream/1885/259038/3/01_Liu_The_impact_of_the_2020.pdf.jpg |
long_lat |
ENVELOPE(-45.166,-45.166,-60.650,-60.650) ENVELOPE(86.000,86.000,-68.617,-68.617) |
geographic |
East Antarctica Rayner Mount Brown |
geographic_facet |
East Antarctica Rayner Mount Brown |
genre |
Antarc* Antarctic Science Antarctica East Antarctica |
genre_facet |
Antarc* Antarctic Science Antarctica East Antarctica |
op_source |
Antarctic Science |
op_relation |
0954-1020 http://hdl.handle.net/1885/259038 doi:10.1017/S0954102019000518 https://openresearch-repository.anu.edu.au/bitstream/1885/259038/3/01_Liu_The_impact_of_the_2020.pdf.jpg |
op_rights |
© Antarctic Science Ltd 2020. http://creativecommons.org/licenses/by/4.0/ Creative Commons Attribution licence |
op_doi |
https://doi.org/10.1017/S0954102019000518 |
container_title |
Antarctic Science |
container_volume |
32 |
container_issue |
1 |
container_start_page |
45 |
op_container_end_page |
57 |
_version_ |
1788059662304673792 |