516 20128 118 8 516 520 2012 8 Jour. Geol. Soc. Japan, Vol. 118, No. 8, p. 516 520, August 2012 JOI: JST.JSTAGE/geosoc/2012.0020 doi: 10.5575/geosoc.2012.0020 Carboniferous ammonoids from the Kawai Limestone of the Akiyoshi Belt, eastern Hiroshima Prefecture, SW Japan Abstract Masayuki Ehiro, Osamu Nishikawa and Isao Nishikawa 2012 2 13 2012 3 31 The Tohoku University Museum, Sendai 980-8578, Japan Mineral Industry Museum, Graduate School of Technology and Resource Science, Akita University, Akita 010-8502, Japan 1797-1 Otsu 1797-1, Yuki, Jinsekikogen-cho, Jinseki-gun, Hiroshima 720-1812, Japan Two Late Carboniferous (late Bashkirian Moscovian) ammonoids, Diaboloceras sp. and Pseudoparalegoceratidae gen. et sp. indet., are described from the Kawai Limestone of the Akiyoshi Belt, eastern Hiroshima Prefecture. This is the first record of Carboniferous ammonoids from the central part of the Akiyoshi Belt. These ammonoids and previously reported foraminiferans and brachiopods show that the age of the Kawai Limestone ranges from Late Carboniferous to Middle Permian. Fossil data indicate that the Kawai Limestone consists of three repetitions of an Upper Carboniferous to Middle Permian stratigraphic sequence. The Carboniferous Permian limestones, sporadically exposed as inliers, along the southern margin of the Akiyoshi Belt in Hiroshima Prefecture are possibly constituents of a large seamount-reef complex. Keywords: Carboniferous ammonoid, Diaboloceras, Kawai Limestone, Akiyoshi Belt, Hiroshima Prefecture Corresponding author; M. Ehiro, ehiro@m.tohoku.ac.jp, 1984; Kanmera et al., 1990,, 1974; Sano and Kanmera, 1988; Sano et al., 2000; Fig. 1A 2 Fig. 1B;, 1996;, 2002 2 The Geological Society of Japan 2012 516 Fig. 1, 2000, 1979 Fig. 21965 1979 Yanagida and Nishikawa1984 Fig. 2 AsselianSakmarian
118 8 517 Fig.. (A) Index map showing the large limestone bodies in the Akiyoshi Belt of the Chugoku District, southwest Japan, and (B) geologic sketch map of the eastern part of Hiroshima Prefecture (simplified from Teraoka et al., 1996, and Matsuura et al., 2002). 1979 Fig. 2 NNW SSE 1987 1988 Yanagida and Nishikawa1984 Fig. 2 5 2 mm 3 Fig. 3 3 2 IGPS coll. cat. no. 111049 111050;
518 20128 Fig.. Geologic map of the Kawai area, Fuchu City, eastern Hiroshima Prefecture. The geologic map is simplified from Sada et al. (1979). Fossil data are from Sada et al. (1979) and Yanagida and Nishikawa (1984). Fig. 3-1, 2 D 20 mm 6 7 UD D 50% 11.5 mm 3 4 2 no. 111049 V first umbilical lobeu 1 second umbilical lobeu 2 2 lobe Fig 3-1d WocklumeriaEpiwocklumeriaSoliclymenia Schistocetatidae Diaboloceras ParalegocerasWelleritidae Winslowoceras Eowellerites Welleritidae 2 Schistocetatidae DiabolocerasMiller and Furnish, 1940 ParalegocerasHyatt, 1884 20 mm, Nassichuk, 1975 Paralegoceras Diaboloceras UD/D U 2 V 20 mm U 2 Diaboloceras Diaboloceras Bashkirian Moscovian Kullmann, 2009Paralegoceras Moscovian Nishida1971 Paralegoceras Diaboloceras? sp. Nassichuk1975 3 IGPS coll. cat. no. 111051; Fig. 3-3 25 mm 15 mm Fig. 3-3c Pseudoparalegoceratidae Phaneroceras Pseudoparalegoceras Pseudoparalegoceratidae gen. et sp. indet. BashkirianKasimovian Kullmann, 2009 2, Nishida, 1971;, 2007 Diaboloceras BashkirianMoscovian Yanagida and Nishikawa 1984 AsselianSakmarian 1979 Triticites? sp. 200 m Pseudofusulina
118 8 519 Fig.. Ammonoid fossils from the Kawai Limestone. 1, Diaboloceras sp. (IGPS coll. cat. no. 111049). 2, Diaboloceras sp. (IGPS coll. cat. no. 111050) 3, Pseudoparalegoceratidae gen. et sp. indet. (IGPS coll. cat. no. 111051). 1a and 2a, lateral views. 1b and 2b, ventral views. 1c, cross section. 1d, external suture line (part). 3a, lateral view. 3b, ventral view. 3c, internal suture line. Scale bars are 10 mm unless otherwise specified. sp. 3 500 m ProfusulinellaPseuodstaffella, 1979 NNW SSE 20 km 10 km 1962, 1964, 1965 Fig. 1B Hase, A., 1962, Geol. Rep. Hiroshima Univ., no.12, 277-294. Hase, A., 1964, Geological Map of Hiroshima Prefecture, 1: 200,000 and Explanatory Text, Naigai Map Co., 31 59. Hase, A., 1965,,,
520 20128 Geol. Rep. Hiroshima Univ., no.14, 277 291. Hase, A., Okimura, Y. and Yokoyama, T., 1974,, Geol. Rep. Hiroshima Univ., no.19, 1 39. Hayasaka, Y., Ishioka, J., Ikeda, K. and Suda, Y., 2000, 23 Monogr. Assoc. Geol. Collab. Japan, no. 49, 81 91. Hyatt, A., 1883-1884, Genera of fossil cephalopods. Proc. Boston Soc. Nat. Hist., 22, 253 338. Ichikawa, K., 1984, Hujita, K. ed., Tectonic Belts of Asia, Kaibundo Publ., 223 238 Kanmera, K., Sano, H. and Isozaki, Y., 1990, Akiyoshi Terrane. In Ichikawa, K., Mizutani, S., Hara, I., Hada, S. and Yao, A., eds., Pre-Cretaceous Tarranes of Japan-Publication of IGCP Project No. 224: Pre-Jurassic Evolution of Eastern Asia, Nippon Insatsu Shuppan Co. Ltd., 49 62. Kullmann, J., 2009, Schistoceratoidea. In Furnish, W. M., Glenister, B. F., Kullmann, J. and Zhou, Z., eds., Treatise on Invertebrate Paleontology, Part L, Mollusca 4Rivised, Volume 2: Carboniferous and Permian AmmonoideaGoniatitida and Prolecanitida, Univ. Kansas, Paleont. Inst., Lawrence, 108 119. Matsuura, H., Kurimoto, C., Yoshida, F., Saito, Y., Makimoto, H., Toshimitsu, S., Iwaya, T., Komazawa, M. and Hiroshima, T., 2002, 20 1 1: 200,000 Geological Map of Japan, NI-53-27, Okayama and Marugame Geol. Surv. Japan, AIST Miller, A. K. and Furnish, W. M., 1940, Studies of Carboniferous ammonoids: Part 5-7. Jour. Paleont., 14, 521 543. Nassichuk, W. W., 1975, Carboniferous ammonoids and stratigraphy in the Canadian Arctic Archipelago. Bull. Geol. Surv. Canada, 237, 1 240. Nishida, T., 1971, Carboniferous ammonoids from Akiyoshi Molluscan paleontology of the Akiyoshi Limestone Group-IV. Bull. Akiyoshi-dai Sci. Mus., no. 7, 1 24. Sada, K., Okimura, Y. and Imamura, S., 1979, Mem. Fac. Integr. Arts Sci., Hiroshima Univ., IV Studies Environment. Sci., 4, 23 27 Sano, H. and Kanmera, K., 1988, Paleogeographic reconstruction of accreted oceanic rocks, Akiyoshi, Southwest Japan. Geology, 16, 600 603. Sano, S., Hayasaka, Y. and Tazaki, K., 2000, Geochemical characteristics of Carboniferous greenstones in the Inner Zone of Southwest Japan. Island Arc, 9, 81 96. Teraoka, Y., Matsuura, H., Makimoto, H., Yoshida, F., Kamitani, M., Hiroshima, T., Komazawa, M. and Shichi, R., 1996, 20 1 1: 200,000 Geological Map of Japan, NI-53-26, Takahashi Geol. Surv. Japan Toyama Paleontological Research Club, 2007,,, Catalogue for the Special Exhibition Symphony of life: an Appearance and Extinction of Ammonite Yatsuo Fossil Museum, Toyama, 26 p.in Japanese Yanagida, J. and Nishikawa, I., 1984, Early Permian brachiopods from the Kawai Limestone, Hiroshima Prefecture, Southwest Japan. Mem. Fac. Sci., Kyushu Univ., Ser. D, Geol., 25, 159 197. English translation from the original written in Japanese Ehiro, M., Nishikawa, O. and Nishikawa, I., 2012, Carboniferous ammonoids from the Kawai Limestone of the Akiyoshi Belt, eastern Hiroshima Prefecture, SW Japan. Jour. Geol. Soc. Japan,, 516 520. Diaboloceras sp. 2 Pseudoparalegoceratidae gen. et sp. indet. 1 BashkirianMoscovian 3