10:15 AM - 10:30 AM
[SEM17-06] Reconstruction of the lower Olduvai geomagnetic polarity transition in Chikura Group distributed in the Boso Peninsula
Keywords:Olduvai, polarity transition, Boso Peninsula
The demagnetization methods evaluated in this study are the alternating filed demagnetization (AFD) with 5 mT increments up to 80 mT, the thermal demagnetization (ThD) with 50 °C increments up to 600 °C, a hybrid method consisting of ThD at 250 °C and the AFD sequence. Among those methods, only the Hybrid method provided data passing the reversal test. So, we selected the Hybrid method as to provide paleomagentic data from the study section.
We detected the Reunion Subchronozone and the lower Olduvai polarity transition zone from horizons of 4.7 m and 1.6 m thickness respectively.We obtained an oxygen isotope stratigraphy from the lower sequence covering the Réunion Subchronozone. As the result, the lower and upper boundaries of the Réunion Subchronozone are correlated to MIS 81 and 80 respectively, which are consistent with the result from IODP Site U1308 (Channell et al., 2016).
Reference Okada et al., 2012, Jour. Geol. Soc. Japan, 118, 97–108. Channell et al., 2016, Quat. Sci. Rev. 131, 1-19.