LA-ICP-MS zircon U-Pb age and Hf isotope data from the granitic rocks in the Iwakuni area, Southwest Japan: re-evaluation of emplacement order and the source magma

Oxygen isotope data of quartz from San-yo and Ryoke belt granites, schists, and siliceous veins: constraining the effects of 18O-rich fluids on granitic magma

“…Numerous authors have discussed the occurrence, emplacement order, and magma genesis of the granitoids of the Inner Zone, based on detailed structural relationships in the field, petrographic observations on individual granitic bodies, and geochemical and geochronological results (e.g., Kojima, 1953;Okamura, 1957Okamura, , 1960Koide, 1958;Kawano and Ueda, 1966;Shigeno and Yamaguchi, 1976;Hayasaka et al, 1983;Higashimoto et al, 1983;Okano and Honma, 1983;Kagami et al, 1992;Ikeda, 1993Ikeda, , 1998Owada et al, 1995;Suzuki et al, 1996;Suzuki and Adachi, 1998;Herzig et al, 1998;Nakajima et al, 1993;Ishihara and Matsuhisa, 2002;Ishihara and Chappell, 2007;Akasaki et al, 2013Akasaki et al, , 2015Skrzypek et al, 2016Skrzypek et al, , 2018Nakajima, 2018;Mateen et al, 2019 and references therein). In the forthcoming sections, a discussion is presented on the magma origin, effects of the metasedimentary sources on the magmatic rocks, and the role of fluids that precipitated the late-stage quartz veins.…”

“…and trace element contents (ppm) were analyzed on fused glass beads, prepared from 0.4 g sample powder mixed with 4 g of lithium tetraborate, using the X-Ray Fluorescence spectrometer (Rigaku ZSX-100e) housed at Kagoshima University's Division of Instrumental Analysis Research Support Center and the results are shown in Table 2. During XRF analysis 14 standard reference materials of the GSJ (JA-1, JA-2, JA-3, JB-1a, JB-2, JB-3, JF-1, JF-2, JG-1, JG-1a, JG-2, JG-3, JGb-1, and JP-1; Imai et al, 1995) were used for (t) of granite samples are obtained from zircons as reported in Mateen et al (2019). Source for the age of metamorphic rocks is provided in main text.…”

“…Granites in the San-yo belt also revealed more or less identical ages to those in the Ryoke belt, spanning between 124 to 90 Ma (Higashimoto et al, 1983;Owada et al, 1995;Suzuki et al, 1996;Suzuki and Adachi, 1998). Mateen et al (2019) carried out U-Pb combined with Hf isotope analysis on zircons separated from granites from the San-yo and Ryoke belts and reveled an age span of 106 to 92 Ma. Ikeda (1993Ikeda ( , 1998 identified six metamorphic zones (from north to south) in the Ryoke belt as (1) the chlorite Zone, (2) the chlorite-biotite Zone, (3) the biotite Zone, (4) the muscovite-cordierite Zone, (5) the K-feldspar-cordierite Zone, and (6) the garnet-cordierite Zone (Fig.…”

“…2a and 2b) were used for this study. Petrography and structural or textural features of some of the samples were reported in earlier studies (e.g., Terabayashi et al, 2010;Mateen et al, 2015Mateen et al, , 2019. For the reader's convenience, we reproduce the geological information that is related to this study.…”

Detrital Zircon U-Pb Geochronology and Hf Isotope Geochemistry of the Hayang Group, SE Korea and the Himenoura and Goshoura Groups, SW Japan: Signs of Subduction-Related Magmatism after a Long Resting Period

“…The high ε Hf (t) values of about 120-110 Ma detrital zircons are somewhat different from those previously reported from the Cretaceous to Paleogene granitoids from Southwest Japan. For example, the granitic rocks in the Iwakuni area in Southwest Japan have a zircon U-Pb age of 104-92 Ma and ε Hf (t) in the range of −5 to +0.7 [77]. The results of Sr-Nd isotope analysis for Phanerozoic granitoids from Southwest Japan generally show negative ε Nd (t) values and high initial 87 Sr/ 86 Sr ratios [69].…”