Evaluation of suitability of zircon as standard materials based on thermal history; Example of the Wassogatake Formation in Ishikawa Prefecture

Nagata, Mitsuhiro   ; Nakajima, Toru   ; Fukuda, Shoma   ; Sueoka, Shigeru   ; Yagi, Koshi*; Yokoyama, Tatsunori   

Zircon U-Pb and fission track (FT) dating and moonstone (sanidine) K-Ar dating of the Wassogatake Formation in the southern part of Hakusan City, Ishikawa Prefecture were carried out as part of the search for zircon standard materials for dating. The weighted average U-Pb dates obtained from the three samples are ca. 21.9-21.7 Ma, overlapping within the uncertainty range. Zircon FT and moonstone K-Ar dates were obtained younger ages from some samples. In addition, the track lengths of the three samples are short. Based on the above results, the zircons of the Wassogatake Formation are effective for the high closure temperature dating method (e.g., U-Pb dating), but are not suitable for the low closure temperature dating method (e.g., FT dating).