CRETACEOUS GEOLOGY AND PALEONTOLOGYOF KORYAK

俄罗斯远东堪察加半岛北部的科里亚克高原以分布广泛的海洋白垩纪化石而闻名。然而，白垩纪生物地层学和古生物学对软体动物化石，特别是菊石化石的详细研究还没有得到充分的研究。1998年和1999年夏天，由日本和俄罗斯地质学家和古生物学家组成的联合考察队(东京大学领队田部和志教授)在彭志湾东部沿海地区以及塔洛夫卡河及其支流的中下游进行了实地考察，以了解软体动物动物群的白垩纪生物地层和古生物地理特征。作为我们考察的结果，我们在上阿尔比亚-马斯特里希特层序的不同层位和不同地点获得了大量的菊石和石榴石化石。阿尔比亚和塞诺马尼亚动物群与美国西部内陆省的动物群有亲缘关系，特别是通过新胃碎屑岩的出现。都罗纪和科尼亚克期的菊石动物群主要由北太平洋动物群组成，但缺乏典型的特提斯元素，如大头蛇科。这些资料将为北太平洋地区白垩纪菊石动物群的生物地层学、古生物地理学和系统发育研究提供基本依据。

The Koryak Upland, north of the Kamchatka Peninsula, Far East Russia Has been sell known for the extensive distribution of fossiliferous marine Cretaceous deposits. However, details of the Cretaceous biostratigraphy and paleontology of molluscan fossils, especially ammonites have not yet sufficiently studied.In the summer of 1998 and 1999, a field expedition by a joint team of Japanese and Russian geologists and paleontologists (leader Prof. Kazushige Tanabe of University of Tokyo) was operated in the eastern coastal region of Penzhina Bay and along the lower and middle streams of the Talovka River and its tributaries to understand the Cretaceous biostratigraphy and paleobiogeographic characteristics of the molluscan faunas. As a result of our expedition, large amounts of ammonite and inoceramid fossils have been obtained from various horizons and localities of the Upper Albian - Maastrichitian sequences. The Albian and Cenomanian fauna has an affinity with that of the U.S. Western Interior Province, especially by the occurrence of Neogastroplites. The Turonian and Coniacian ammonoid faunas consist mainly of norht Pacific faunal elements but lack in typical Tethyan elements such as Collignoniceratidae. These data will provide a fundamental basis to consider the biostratigraphy, paleobiogeography and phylogeny of the Cretaceous ammonite faunas in the north Pacific region.