09:15 〜 09:30
[SEM15-02] Investigation of the precursor of Matuyama-Brunhes geomagnetic reversals
キーワード：Geomagnetic reversal, Matuyama-Brunhes reversal, Magnetic precursor, Paleomagnetism
Sampling was carried out within the lower Middle-Pleistocene layers of the Kokumoto formation along the Yoro-River, east-central Japan. More than 30 m of sediments were investigated resulting in 81 sampling stations with a total of 243 samples.
Anisotropy of Magnetic Susceptibility (AMS) was measured to calculate the bedding correction. Thermal (TD) and Alternating field (AF) demagnetization were performed to extract the Characteristic Remanent Magnetization (ChRM) through Principal Component Analysis (PCA). Finally, Virtual Geomagnetic Poles (VGP) and Relative Peloeointensity (RPI) were calculated to discuss the behavior of the earth magnetic field during the span of time investigated.
VGP results show clear transitional directions between -25m and -30 m within the reverse chron of Matuyama. In the same interval of depth, RPI values show significant low values supporting the transitional direction of the VGP. Those results put in perspective with the data from Haneda et al 2020 article confirmed the presence of Matuyama-Brunhes precursor in the Chiba composite section.
Anisotropy of Magnetic Susceptibility (AMS) was measured to calculate the bedding correction. Thermal (TD) and Alternating field (AF) demagnetization were performed to extract the Characteristic Remanent Magnetization (ChRM) through Principal Component Analysis (PCA). Finally, Virtual Geomagnetic Poles (VGP) and Relative Peloeointensity (RPI) were calculated to discuss the behavior of the earth magnetic field during the span of time investigated.
VGP results show clear transitional directions between -25m and -30 m within the reverse chron of Matuyama. In the same interval of depth, RPI values show significant low values supporting the transitional direction of the VGP. Those results put in perspective with the data from Haneda et al 2020 article confirmed the presence of Matuyama-Brunhes precursor in the Chiba composite section.