Sm-Nd AND Rb-Sr ISOCHRON AGES FOR META-TRONDHJEMITES FROM CAPE HINODE, EAST ANTARCTICA
A Rb-Sr and Sm-Nd isotope study of meta-trondhjemites and a pelitic gneiss from Cape Hinode, Lutzow-Holm Complex (LHC), East Antarctica has been performed. A Sm-Nd whole rock isochron for nine meta-trondhjemites defines an age of 1031±69Ma with an initial ^<143>Nd/^<144>Nd ratio of 0.511...
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National Institute of Polar Research
1995
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ftnipr:oai:nipr.repo.nii.ac.jp:00002791 2023-05-15T13:49:00+02:00 Sm-Nd AND Rb-Sr ISOCHRON AGES FOR META-TRONDHJEMITES FROM CAPE HINODE, EAST ANTARCTICA シライシ カズユキ カガミ ヒロオ ヤナイ ケイゾウ Kazuyuki SHIRAISHI Hiroo KAGAMI Keizo YANAI 1995-09 https://nipr.repo.nii.ac.jp/?action=repository_uri&item_id=2791 http://id.nii.ac.jp/1291/00002791/ https://nipr.repo.nii.ac.jp/?action=repository_action_common_download&item_id=2791&item_no=1&attribute_id=18&file_no=1 en eng National Institute of Polar Research Institute for Study of the Earth's Interior, Okayama University National Institute of Polar Research:(Present address)Faculty of Technology, Iwate University https://nipr.repo.nii.ac.jp/?action=repository_uri&item_id=2791 http://id.nii.ac.jp/1291/00002791/ AA1072335X Proceedings of the NIPR Symposium on Antarctic Geosciences, 8, 130-136(1995-09) https://nipr.repo.nii.ac.jp/?action=repository_action_common_download&item_id=2791&item_no=1&attribute_id=18&file_no=1 Departmental Bulletin Paper P(論文) 1995 ftnipr 2022-11-26T19:42:11Z A Rb-Sr and Sm-Nd isotope study of meta-trondhjemites and a pelitic gneiss from Cape Hinode, Lutzow-Holm Complex (LHC), East Antarctica has been performed. A Sm-Nd whole rock isochron for nine meta-trondhjemites defines an age of 1031±69Ma with an initial ^<143>Nd/^<144>Nd ratio of 0.5115520±0.000053 (MSWD=0.10,ε_<Nd>=+4.7±1.0). In the Rb-Sr isochron diagram, the same nine samples yield an age of 1273±104Ma with an initial ^<87>Sr/^<86>Sr ratio of 0.70275±0.00017 (MSWD=7.4) although the data are slightly scattered. The Sm-Nd isochron age is indistinguishable from the previously reported U-Pb SHRIMP zircon age (1017±13Ma). Nd model ages (T_<DM>) of the metatrondhjemites and a pelitic gneiss are ∿1.2-1.5Ga and 2Ga, respectively. Taking into account the initial ratios and the previous zircon study, we conclude that the ∿1000Ma age indicates the time of igneous crystallization of the trondhjemite. The pelitic gneiss, which probably originated from middle Proterozoic supracrustal material, is the host rock of the trondhjemite intrusion. However, the ∿500Ma high grade metamorphic age, which is ubiquitous in the LHC, is not documented in these rocks. Slight scattering in the Rb-Sr and Sm-Nd isochron diagrams might be the effect of the ∿500Ma metamorphism, but resetting of the isotopes was not complete, probably because of the scale of the 4km×5km sample collection area. Report Antarc* Antarctica East Antarctica National Institute of Polar Research Repository, Japan East Antarctica Cape Hinode ENVELOPE(42.633,42.633,-68.117,-68.117) |
institution |
Open Polar |
collection |
National Institute of Polar Research Repository, Japan |
op_collection_id |
ftnipr |
language |
English |
description |
A Rb-Sr and Sm-Nd isotope study of meta-trondhjemites and a pelitic gneiss from Cape Hinode, Lutzow-Holm Complex (LHC), East Antarctica has been performed. A Sm-Nd whole rock isochron for nine meta-trondhjemites defines an age of 1031±69Ma with an initial ^<143>Nd/^<144>Nd ratio of 0.5115520±0.000053 (MSWD=0.10,ε_<Nd>=+4.7±1.0). In the Rb-Sr isochron diagram, the same nine samples yield an age of 1273±104Ma with an initial ^<87>Sr/^<86>Sr ratio of 0.70275±0.00017 (MSWD=7.4) although the data are slightly scattered. The Sm-Nd isochron age is indistinguishable from the previously reported U-Pb SHRIMP zircon age (1017±13Ma). Nd model ages (T_<DM>) of the metatrondhjemites and a pelitic gneiss are ∿1.2-1.5Ga and 2Ga, respectively. Taking into account the initial ratios and the previous zircon study, we conclude that the ∿1000Ma age indicates the time of igneous crystallization of the trondhjemite. The pelitic gneiss, which probably originated from middle Proterozoic supracrustal material, is the host rock of the trondhjemite intrusion. However, the ∿500Ma high grade metamorphic age, which is ubiquitous in the LHC, is not documented in these rocks. Slight scattering in the Rb-Sr and Sm-Nd isochron diagrams might be the effect of the ∿500Ma metamorphism, but resetting of the isotopes was not complete, probably because of the scale of the 4km×5km sample collection area. |
format |
Report |
author |
シライシ カズユキ カガミ ヒロオ ヤナイ ケイゾウ Kazuyuki SHIRAISHI Hiroo KAGAMI Keizo YANAI |
spellingShingle |
シライシ カズユキ カガミ ヒロオ ヤナイ ケイゾウ Kazuyuki SHIRAISHI Hiroo KAGAMI Keizo YANAI Sm-Nd AND Rb-Sr ISOCHRON AGES FOR META-TRONDHJEMITES FROM CAPE HINODE, EAST ANTARCTICA |
author_facet |
シライシ カズユキ カガミ ヒロオ ヤナイ ケイゾウ Kazuyuki SHIRAISHI Hiroo KAGAMI Keizo YANAI |
author_sort |
シライシ カズユキ |
title |
Sm-Nd AND Rb-Sr ISOCHRON AGES FOR META-TRONDHJEMITES FROM CAPE HINODE, EAST ANTARCTICA |
title_short |
Sm-Nd AND Rb-Sr ISOCHRON AGES FOR META-TRONDHJEMITES FROM CAPE HINODE, EAST ANTARCTICA |
title_full |
Sm-Nd AND Rb-Sr ISOCHRON AGES FOR META-TRONDHJEMITES FROM CAPE HINODE, EAST ANTARCTICA |
title_fullStr |
Sm-Nd AND Rb-Sr ISOCHRON AGES FOR META-TRONDHJEMITES FROM CAPE HINODE, EAST ANTARCTICA |
title_full_unstemmed |
Sm-Nd AND Rb-Sr ISOCHRON AGES FOR META-TRONDHJEMITES FROM CAPE HINODE, EAST ANTARCTICA |
title_sort |
sm-nd and rb-sr isochron ages for meta-trondhjemites from cape hinode, east antarctica |
publisher |
National Institute of Polar Research |
publishDate |
1995 |
url |
https://nipr.repo.nii.ac.jp/?action=repository_uri&item_id=2791 http://id.nii.ac.jp/1291/00002791/ https://nipr.repo.nii.ac.jp/?action=repository_action_common_download&item_id=2791&item_no=1&attribute_id=18&file_no=1 |
long_lat |
ENVELOPE(42.633,42.633,-68.117,-68.117) |
geographic |
East Antarctica Cape Hinode |
geographic_facet |
East Antarctica Cape Hinode |
genre |
Antarc* Antarctica East Antarctica |
genre_facet |
Antarc* Antarctica East Antarctica |
op_relation |
https://nipr.repo.nii.ac.jp/?action=repository_uri&item_id=2791 http://id.nii.ac.jp/1291/00002791/ AA1072335X Proceedings of the NIPR Symposium on Antarctic Geosciences, 8, 130-136(1995-09) https://nipr.repo.nii.ac.jp/?action=repository_action_common_download&item_id=2791&item_no=1&attribute_id=18&file_no=1 |
_version_ |
1766250313229008896 |