Persistent shallow magnetic inclination in the past 5 million years with implications for regional tectonics in the Philippines

Journal of Asian Earth Sciences: X

Hidetoshi Shibuya¹  Carla B. Dimalanta²  Jonathan T. Macuroy³  Decibel V. Faustino-Eslava³  Graciano P. Yumul, Jr.⁴ 

[1] Corresponding author.;Department of Earth Sciences, Kumamoto University, Kurokami 2-chome, Kumamoto, Japan;Earth Systems Research Team, School of Environmental Science and Management, University of the Philippines Los Baños, Laguna, Philippines;Rushurgent Working Group, National Institute of Geological Science, College of Science, University of the Philippines, Diliman, Quezon City, Philippines;

关键词: Paleosecular variation of lavas (PSVL);    Shallow inclination anomaly;    Luzon;    Philippines;   

DOI  :  

来源: DOAJ

【 摘 要 】

Despite the growing knowledge on geomagnetic paleosecular variations, the region around the Philippine archipelago remains to be a huge data gap in this regard. This work looked into rock magnetic information from <5 Ma volcanic rocks of Luzon Island to provide data for the statistical characterization of the time-averaged field in the region.A total of 21 sites with ages from 1 ka to 4.3 Ma yielded 13 normal, 7 reversed, and 1 intermediate polarity dataset. These were aggregated with previously published work to form a combined dataset of 59 normal + reversed sites with a mean virtual geomagnetic pole at 321.1°E and 83.7°N with α95 = 3.4, and an angular standard deviation of about 14.6°. This amount of scatter is slightly larger than that predicted by Model G but relatively comparable with other near-equatorial regions such as Java and Ecuador. This work is a first examination of paleomagnetic data from the Philippines in relation to the long-term behavior of the magnetic field in this part of Southeast Asia. The long-ranging shallow inclination observed may also have implications on how paleomagnetic data are interpreted for tectonic studies in the region.

【 授权许可】

Unknown