THE MAGNETIC ANISOTROPY OF GNEISSIC ROCKS FROM THE SKARVSNES AREA, EAST ANTARCTICA

• Main Authors: ナカイ ムツミ, フナキ ミノル /, Mutsumi NAKAI, Minoru FUNAKI, Peter WASILEWSKI
• Format: Report
• Language: English
• Published: Department of Polar Science, The Graduate University for Advanced Studies (National Institute of Polar Research) 1993
• Subjects: East Antarctica; Skarvsnes; Antarc*; Antarctica; Geomagnetic Pole
• 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

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.