Magnetic analysis of Antactic ordinary chondrites and achondrites on the basis of a magnetic binary system model
Magnetic hysteresis cycles of 9 ordinary chondrites and 10 achondrites, collected mainly from Antarctica, are analyzed on the basis of a newly proposed model of a non-interactive magnetic binary system, by taking into account their thermomagnetic characteristics for identifying ferromagnetic phases...
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National Institute of Polar Research
1989
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ftnipr:oai:nipr.repo.nii.ac.jp:00004493 2023-05-15T13:49:01+02:00 Magnetic analysis of Antactic ordinary chondrites and achondrites on the basis of a magnetic binary system model Takesi Nagata Minoru Funaki 1989-10 https://nipr.repo.nii.ac.jp/?action=repository_uri&item_id=4493 http://id.nii.ac.jp/1291/00004493/ https://nipr.repo.nii.ac.jp/?action=repository_action_common_download&item_id=4493&item_no=1&attribute_id=18&file_no=1 en eng National Institute of Polar Research https://nipr.repo.nii.ac.jp/?action=repository_uri&item_id=4493 http://id.nii.ac.jp/1291/00004493/ AA10784627 Proceedings of the NIPR Symposium on Antarctic Meteorites, 2, 310-325(1989-10) https://nipr.repo.nii.ac.jp/?action=repository_action_common_download&item_id=4493&item_no=1&attribute_id=18&file_no=1 Departmental Bulletin Paper P(論文) 1989 ftnipr 2023-01-28T20:04:07Z Magnetic hysteresis cycles of 9 ordinary chondrites and 10 achondrites, collected mainly from Antarctica, are analyzed on the basis of a newly proposed model of a non-interactive magnetic binary system, by taking into account their thermomagnetic characteristics for identifying ferromagnetic phases involved. All the chondrites and achondrites examined consist of a high-coercivity (a) component and a low-coercivity (b) component. In ordinary chondrites, the (a) component is often identified to be tetrataenite (tetragonal-ordered crystal of FeNi) having an apparent coercive force H^<(a)>_C≳10^3 Oe (TT-type phase), while in other chondrites the (a) component comprises fine grains of shape-anisotropic single-domain structure (A. SD-type phase) having H^<(a)>_C=(2∿5)×10^2 Oe. The (b) component consists of mostly multi-domain grains of kamacite and/or taenite of H^<(b)>_C≲20 Oe. In most achondrites, the (a) component comprises A. SD-type phase of H^<(a)>_C=(2∿5)×10^2 Oe except a special case consisting of a small amount of tetrataenite. The structure of the (b) component in achondrites is the same as in ordinary chondrites. An anomalous hump-shape rise in saturation magnetization (I_s) between 330℃ and Curie point of taenite (540∿590℃) during the initial heating process is found in diogenites and a eucrite. The thermomagnetic hump is considered here to be due to an increase of A. SD-type phase of taenite associated with a relatively smaller increase of the (b) component multi-domain phase. However, a possible metallographical interpretation of the hump phenomenon has not yet been obtained. Report Antarc* Antarctica National Institute of Polar Research Repository, Japan Curie Point ENVELOPE(-63.483,-63.483,-64.833,-64.833) The Hump ENVELOPE(-63.250,-63.250,-64.367,-64.367) |
institution |
Open Polar |
collection |
National Institute of Polar Research Repository, Japan |
op_collection_id |
ftnipr |
language |
English |
description |
Magnetic hysteresis cycles of 9 ordinary chondrites and 10 achondrites, collected mainly from Antarctica, are analyzed on the basis of a newly proposed model of a non-interactive magnetic binary system, by taking into account their thermomagnetic characteristics for identifying ferromagnetic phases involved. All the chondrites and achondrites examined consist of a high-coercivity (a) component and a low-coercivity (b) component. In ordinary chondrites, the (a) component is often identified to be tetrataenite (tetragonal-ordered crystal of FeNi) having an apparent coercive force H^<(a)>_C≳10^3 Oe (TT-type phase), while in other chondrites the (a) component comprises fine grains of shape-anisotropic single-domain structure (A. SD-type phase) having H^<(a)>_C=(2∿5)×10^2 Oe. The (b) component consists of mostly multi-domain grains of kamacite and/or taenite of H^<(b)>_C≲20 Oe. In most achondrites, the (a) component comprises A. SD-type phase of H^<(a)>_C=(2∿5)×10^2 Oe except a special case consisting of a small amount of tetrataenite. The structure of the (b) component in achondrites is the same as in ordinary chondrites. An anomalous hump-shape rise in saturation magnetization (I_s) between 330℃ and Curie point of taenite (540∿590℃) during the initial heating process is found in diogenites and a eucrite. The thermomagnetic hump is considered here to be due to an increase of A. SD-type phase of taenite associated with a relatively smaller increase of the (b) component multi-domain phase. However, a possible metallographical interpretation of the hump phenomenon has not yet been obtained. |
format |
Report |
author |
Takesi Nagata Minoru Funaki |
spellingShingle |
Takesi Nagata Minoru Funaki Magnetic analysis of Antactic ordinary chondrites and achondrites on the basis of a magnetic binary system model |
author_facet |
Takesi Nagata Minoru Funaki |
author_sort |
Takesi Nagata |
title |
Magnetic analysis of Antactic ordinary chondrites and achondrites on the basis of a magnetic binary system model |
title_short |
Magnetic analysis of Antactic ordinary chondrites and achondrites on the basis of a magnetic binary system model |
title_full |
Magnetic analysis of Antactic ordinary chondrites and achondrites on the basis of a magnetic binary system model |
title_fullStr |
Magnetic analysis of Antactic ordinary chondrites and achondrites on the basis of a magnetic binary system model |
title_full_unstemmed |
Magnetic analysis of Antactic ordinary chondrites and achondrites on the basis of a magnetic binary system model |
title_sort |
magnetic analysis of antactic ordinary chondrites and achondrites on the basis of a magnetic binary system model |
publisher |
National Institute of Polar Research |
publishDate |
1989 |
url |
https://nipr.repo.nii.ac.jp/?action=repository_uri&item_id=4493 http://id.nii.ac.jp/1291/00004493/ https://nipr.repo.nii.ac.jp/?action=repository_action_common_download&item_id=4493&item_no=1&attribute_id=18&file_no=1 |
long_lat |
ENVELOPE(-63.483,-63.483,-64.833,-64.833) ENVELOPE(-63.250,-63.250,-64.367,-64.367) |
geographic |
Curie Point The Hump |
geographic_facet |
Curie Point The Hump |
genre |
Antarc* Antarctica |
genre_facet |
Antarc* Antarctica |
op_relation |
https://nipr.repo.nii.ac.jp/?action=repository_uri&item_id=4493 http://id.nii.ac.jp/1291/00004493/ AA10784627 Proceedings of the NIPR Symposium on Antarctic Meteorites, 2, 310-325(1989-10) https://nipr.repo.nii.ac.jp/?action=repository_action_common_download&item_id=4493&item_no=1&attribute_id=18&file_no=1 |
_version_ |
1766250471641579520 |