Furehter absolute paleointensity determination of welded tuffs correlated with widespread tephras: Absolute calibration of a relative paleointensity stack

Widespread tephras are observed in marine sediment cores which are often correlated with oxygen isotope stratigraphy. If we obtain absolute paleointensities from welded tuffs correlated with these widespread tephras, we can correlate measured absolute paleointensities with stratigraphic positions in oxygen stratigraphy. Based on tephrochronologic correlation in oxygen isotope stratigraphy, we can compare the absolute paleointensities from the welded tuffs with a relative paleointensity stack with virtually no error in age. Mochizuki et al. (2013) reported paleointensities from welded tuffs of Aso-1, Aso-2, Aso-3 and Aso-4. Also, paleointensity data were reported for B-M polarity reversal (e.g. Chauvin et al ., 1990; Mochizuki et al., 2011), Laschamp excursion (e.g. Roperch et al., 1988; Mochizuki et al., 2006), and Iceland Basin excursion (Yamamoto et al., 2010). On the basis of 7 paleointensity data (calibration points), Mochizuki et al. (in prep.) compared these absolute paleointensity data with a relative paleointensity stack (PISO-1500; Channell et al., 2009). They suggested that relative paleointensities are linearly correlated with the absolute paleointensities. In this study, we measure absolute paleointensities from welded tuffs to increase younger and/or older paleointensity data. we will report absolute paleointensities from 14 welded tuffs (Funakura, Ito, Komagatake-i, Shikotsu-1, Kuttara-3, Ata, Kuucharo-4, Otawara, Kakuto, Shimokado, Imaichi, Yabakei, Ashino and Kumado) which have been correlated with widespread tephras. Also we will compare these absolute paleointensity data with the relative paleointensity stack.