Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Nagata, Mitsuhiro; Fukuda, Shoma; Sueoka, Shigeru; Yokoyama, Tatsunori; Kagami, Saya; Niki, Sota*; Iwano, Hideki*; Danhara, Toru*; Ogita, Yasuhiro; Kajita, Yuya*; et al.
no journal, ,
no abstracts in English
Kagami, Saya; Yokoyama, Tatsunori; Niki, Sota*; Sakata, Shuhei*; Umeda, Koji*; Okada, Rina*; Kondo, Misaki*
no journal, ,
Tephras from submarine eruptions are easily affected by secondary deposition and alteration and the constraints on their geochronology may be difficult. In this study, we conducted zircon U-Th disequilibrium dating by LA-ICP-MS for Zenikame-Menagawa tephra (Z-M), which was erupted from Zenakame volcano on the seafloor of the Tsugaru Strait and is a valid age indicator for MIS3. The zircons in the Toya pumice were measured to evaluate the accuracy of the method and their isochron age of 128 ka was obtained. This result is consistent with the previous reported data by the same method used in this study. We measured the zircons from Z-M and found that many of the zircons did not record eruption ages, and that many grains had U-Th disequilibrium model ages of about 100 ka. In the future, we will attempt U-Th disequilibrium dating of each zircon along with understanding its characteristics (shape, chemical composition and so on).
Nagae, Daisuke; Takemuara, Makoto*; Ueno, Hideki*; Kameda, Daisuke*; Asahi, Koichiro*; Yoshimi, Akihiro*; Sugimoto, Takashi*; Nagatomo, Takashi*; Kobayashi, Yoshio*; Uchida, Makoto*; et al.
no journal, ,
An electric quadrupole moment (
moment) is sensitive to collective aspects of nuclear structure. In the -moment measurement for unstable nuclei, we employ the 
-detected nuclear-quadrupole resonance method. In this method, we need to supply 
resonance frequencies, where 
denotes the nuclear spin. We have developed a new RF-application system to induced all of the transitions. The application of the frequencies may be pursued in two different ways; the sequential RF pulse method and the mixed-wave RF pulse method. We confirmed the reversal of polarization for the both methods, from measurements of -ray asymmetry change for polarized 
B. Using this system, the moments of 
Al have been measured to be 
mb and 
mb by the sequential RF pulse method.