頻繁に起こる地磁気エクスカーション
ブルネ正磁極期のレビュー
2005 年 114 巻 2 号 p. 174-193
詳細
2005 年 114 巻 2 号 p. 174-193
Until now, a large number of records of geomagnetic excursions have been reported both for volcanic rocks and sedimentary sequences. By straightening up the, extensive excursion records, 23 geomagnetic excursions were identified in total for the Brunhes. Eighteen out of 23 excursions are considered to be reliably determined and dated. Above all, Mono Lake (32-34 ka), Laschamp (39-41 ka), Blake (115-122 ka) and Iceland Basin (180-190 ka) are well-documented worldwide excursions. Others include Hilina Pali (18-23 ka), Norwegian-Greenland Sea (60-80 ka), Albuquerque (140-160 ka), Jamaica/Pringle Falls (210-220 ka), Fram Strait (255-265 ka), Kolbeinsey Ridge (280-290 ka), Calabrian Ridge 1 (310-320 ka), Agulhas Ridge (330-340 ka), Weinen (400-420 ka), West Eifel (500-510 ka), Calabrian Ridge 2 (535-545 ka), Emperor/Big Lost (550-570 ka), Calabrian Ridge 3 (580-605 ka), and Delta (665-690 ka). Most of these excursions can be correlated with minima in relative paleointensity records of Sint-800 and ODP Site 983, suggesting that excursions occur due to dominance of a non-dipole field at minima of the main dipole field intensity.
