A preliminary study of secondary magnetization during successive heating of rocks from the Napier Complex

• Main Authors: Naoko Ueno, Tomoko Ogishima, Naoto Ishikawa, Minoru Funaki
• Format: Report
• Language: English
• Published: Natural Science Laboratory, Toyo University 1998
• Subjects: paleointensity; Thelliers method; secondary magnetization; the Napier Complex; Riiser-Larsen; Napier; Antarc*; Polar geoscience
• Online Access: https://nipr.repo.nii.ac.jp/?action=repository_uri&item_id=3023; http://id.nii.ac.jp/1291/00003023/; https://nipr.repo.nii.ac.jp/?action=repository_action_common_download&item_id=3023&item_no=1&attribute_id=18&file_no=1

Secondary magnetization produced during a thermal experiment in Thelliers' method was studied on 12 samples from the Mt. Riiser-Larsen area for that paleomagnetic data already been reported (N. ISHIKAWA and M. FUNAKI: Proc. NIPR Symp. Antarct. Geosci., 10, 79, 1997), and considered suitable for paleomagnetic study from the rock magnetic characteristics of samples. A remeasurement test of NRM on the same temperature step (NRM-check) as well as PTRM (PTRM-check) in air and in vacuum revealed secondary magnetization concerned with NRM and TRM which appeared at the same temperature, around 350℃, that would be explained by the oxidation of sulfide observed under a microscope. Secondary magnetization around 550℃ which appeared in air might also be caused by magneto-mineralogical change. These results are supported by the large variation of initial susceptibility around 300℃ and 550℃. Both the secondary magnetization of NRM and that of PTRM produced in vacuum were comparable to in air.