Data related to the analysis of the Early Paleocene (Danian) tuff discovered from the Yezo Group in the Yubari area, Hokkaido, Northeast Japan.

Fig. A1. Stratigraphic correlation of the upper and uppermost part of the Yezo Group. Abbreviations Fm: Formation, Gp.: Group, Mbr.: Member. 1: Ando and Ando (2002), 2: Ando and Tomosugi (2005), 3: Takahashi et al. (2003), 4: Takashima et al. (2004), 5: Hoyanagi et al. (2007), This study, 6: Hayashi et al. (2011), 7: Kanie and Sakai (2002). 

Fig. A2. a) Panorama photograph of the outcrop of the Hakobuchi Formation. The rectangle (b) denotes the area of Fig. A1b. Abbreviations cg.: conglomerate, Hb: Haborogawa Formation, Hk: Hakobuchi Formation, ss.: sandstone. b) Enlarged photograph of the outcrop near the dating sample. White scale bar is 1 m. (Ⅰ) and (Ⅱ) denote the range of the columnar section in Fig. 2a.

Fig. A3. Route map of Loc. 1 in Fig. 1b. Abbreviation Fm: Formation.

Fig. A4. a) Wetherill Concordia diagram of IS2. Red solid circles indicate concordant datasets. Blue open circles indicate discordant dates. b) Examples of cathodoluminescence (CL) images of zircon grains from sample IS2. White circles show measurement spots (25 μm). The ²⁰⁶U/²³⁸Pb date of each spot is indicated. Scale bar is 100 μm. Yellow numbers  indicate the Th/U ratio of zircon grains.

Document 1. Procedures from zircon separation to U–Pb dating.

Table A1. LA-ICPMS analytical setting and conditions for U–Pb zircon dating.

Table A2. The U–Pb isotopic data of IS2 (tuff sample) and secondary standard zircons.