THE MAGNETIC ANISOTROPY OF GNEISSIC ROCKS FROM THE SKARVSNES AREA, EAST ANTARCTICA
The relationship between magnetic anisotropy and natural remanent magnetization (NRM) was investigated in the gneissic rocks collected from Skarvsnes, Lutzow-Holm Bay, East Antarctica. About 60% of the samples show clear gneissosity, but 40% of the samples have less clear gneissosity. The samples wi...
| Main Authors: | , , , , |
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| Format: | Report |
| Language: | English |
| Published: |
Department of Polar Science, The Graduate University for Advanced Studies (National Institute of Polar Research)
1993
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| Subjects: | |
| Online Access: | https://nipr.repo.nii.ac.jp/?action=repository_uri&item_id=2717 http://id.nii.ac.jp/1291/00002717/ https://nipr.repo.nii.ac.jp/?action=repository_action_common_download&item_id=2717&item_no=1&attribute_id=18&file_no=1 |
| Summary: | The relationship between magnetic anisotropy and natural remanent magnetization (NRM) was investigated in the gneissic rocks collected from Skarvsnes, Lutzow-Holm Bay, East Antarctica. About 60% of the samples show clear gneissosity, but 40% of the samples have less clear gneissosity. The samples with gneissic fabric show magnetic anisotropy. The maximum value of H_C and I_R, and the minimum values of X_<diff> coincide with the lineation within a foliation plane. During thermal demagnetization of the samples having stable NRM's, the NRM declinations are gradually shifted toward the direction of lineation, and they are stabilized in a plane, within the rock, having well developed foliation. The anisotropy tendency is more clearly observed by using the H_C and I_R values than X_<diff> values. Two kinds of virtual geomagnetic pole (VGP) positions are identified from the Skarvsnes area. The former is consistent (latitude 11.2°S, longitude 16.0°E) with the previous results reported from the Lutzow-Holm Bay area, and the latter (latitude 2.5°S, longitude 63.2°E) reflects the magnetic anisotropy resulting from the lineation. |
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