U-Pb zircon dates from the Utaosa Rhyolite of the Teragi Group

Nagata, Mitsuhiro   ; Fukuda, Shoma   ; Sueoka, Shigeru   ; Nakajima, Toru   ; Kajita, Yuya*; Minami, Saki*; Okamoto, Akira*; Tagami, Takahiro*

We performed U-Pb dating on zircons from the Utaosa Rhyolite of the Teragi Group as part of the search for standard materials for dating of zircons. Previous studies about Utaosa Rhyolite have reported ca. 2.30-2.77 Ma zircon fission track, zircon (U-Th)/He, and biotite K-Ar ages. U-Pb dating was carried out on the multi-collector inductively coupled plasma mass spectrometer with a laser ablation system. The weighted mean U-Pb ages of 2.650.16 Ma and 2.660.15 Ma were obtained from two samples. These ages are consistent with the ages from the previous studies. Therefore the results show that zircons from the Utaosa Rhyolite may be effective as a standard material.