New zircon reference material of Late Cretaceous age, SoriZ zircon from the Sori Granodiorite in Japan

Abstract

The Cretaceous period is a significant time for igneous activities in the geological history of the Japanese Islands and the eastern margin of the Asian continent (e.g., Isozaki et al., 2010). Thus, we frequently need to compare the age data of that time. However, there is currently a lack of secondary zircon standards in the Cretaceous. Ogasawara et al. (2013) proposed SoriZ93 from the Sori Granodiorite, Northeast Japan, as a possible Cretaceous zircon reference material. We obtained a new large block of the Sori granodiorite from the same quarry as SoriZ93, and separated zircon grains (SoriZ). In this study, we examine further characteristics of zircon grains from the Sori Granodiorite, and date zircons using the U-Pb CA-ID-TIMS method. The zircon grains were dated by CA-ID-TIMS and LA-ICP-MS to establish the secondary reference material in the Late Cretaceous. As a result, SoriZ zircons (94.15 Ma) are suitable for secondary reference materials in the Late Cretaceous.