Rock magnetic analysis for samples of the Napier Complex in the Mt. Riiser-Larsen area, East Antarctica

• Main Authors: Ishikawa, Naoto, Funaki, Minoru
• Language: English
• Published: National Institute of Polar Research 1998
• Subjects: the Napier Complex; Mt. Riiser-Larsen; rock magnetism; AMS; hysteresis parameters; East Antarctica; Napier; Riiser-Larsen; Antarc*; Antarctica; Polar geoscience
• Online Access: https://nipr.repo.nii.ac.jp/record/3022/files/KJ00000044139.pdf; https://doi.org/10.15094/00003022; https://nipr.repo.nii.ac.jp/records/3022

P(論文) Samples collected at eight sites from granulites of the Archean Napier Complex and dolente dikes intruding the complex in the Mt. Riiser-Larsen area, East Antarctica, were analyzed rock-magnetically in order to assess the stability of their natural remanent magnetizations (NRMs). Results of isothermal remanence acquisition experiments and hysteresis measurements indicate the presence of magnetite in the pseudo-single to multi domain size, which is consistent with N. ISHIKAWA and M. FUNAKI (Proc. NIPR Symp. Antarct. Geosci., 10, 79, 1997). Stable magnetic components carried by fine-grained magnetites were isolated from some sites. Samples with such components may have a mixture of magnetites with different grain sizes although the effect of the mixing was not clearly observed. Heavily-deformed samples were found to be magnetically amsotropic, while magnetic fabrics of less-deformed samples indicate the possibility that the fabrics are of primary origin. The high-stability magnetic components from the less-deformed dolente samples of one site with primary magnetic fabrics may be of primary remanence acquired in the emplacement of the dike at 0.8-1.0Ga. departmental bulletin paper