Fundamental research on Paleogene dinoflagellate cyst biostratigraphy in Southwest Japan

日本西南部古近纪甲藻包囊生物地层学的基础研究

基本信息

批准号：
14540438
负责人：
KURITA Hiroshi
金额：
$ 2.3万
依托单位：
NIIGATA UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2002
资助国家：
日本
起止时间：
2002 至 2003
项目状态：
已结题

项目摘要

1)Surface geologlcal investigation was conducted on the Paleogene Tertiary formations in northwestern Kyushu and westernmost part of Honshu in terms of (a)sedimentary facies analysis, (b)sampling of fine-grained sediments for dinoflagellate cyst analysis, and (c)sampling of molluscan fossils. Logged sections include the Shimoshima Group in the Amakusa area, the Takashima and Iojima Groups in the Takashima area, the Matsushima and Nishisonogi Groups in the Sakito-Matsushima area, the Ainoura and Sasebo Groups in the Sasebo area, the Ouchi and Kishima Groups in the Karatsu area, the Ashiya Group in the Chikuho area, the Hioki Group in the Yuyawan area, and the Manda Group in the Miike area. The overall sampled interval ranges from the Middle Eocene to latest Oligocene in age, based on previous studies.2)Successive occurrences of fossil dinoflagellate cysts were confirmed from most marine intervals of the logged section. The assemblages, being generally diverse, include genera such as Gla … More phyrocysta, Spiniferites, Homotryblium, Cordosphaeridium, Hystrichokolpoma, Heteraulacacysta, Deflandrea, Dracodinium and Wetzeliella. They showed apparent stratigraphic changes, which is positive for feasible blostratigraphic potential in Southwest Japan. A preliminary biostratigraphic zonation was presented. In addition, the constituents of the assemblages are mostly common to those from the coeval sediments in the East China Sea, although at the same time they are very different from those from the Hokkaido-Sakhalin region. This supports the paleobiogeographic differentiation along the northwestern coast of the Pacific that became apparent probably during the Terminal Eocene, which requires independent biostratigraphic schemes for higher latitudes and lower latitudes.3)Our investigation of molluscan fossils indicated that the assemblages from the Sasebo Group should be attributed to the Ashiya Fauna, lacking the elements typical to the Kadonosawa Fauna. This implies that the age range of the Saseboan Stage should not extend up to the Miocene. Less

1）对九州西北部和本州最西部的古近纪地层进行了地表地质调查，包括（a）沉积相分析，（b）细粒沉积物取样用于甲藻包囊分析，以及（c）取样软体动物化石包括天草地区的下岛群、高岛群和伊王岛群。高岛地区的松岛群、西彼野群、崎户松岛地区的松岛群、西园群、佐世保地区的相浦群、佐世保群、唐津地区的大内群、岸岛群、筑丰地区的芦屋群、日置群Yuyawan地区和Miike地区的Manda群，总体采样区间为始新世中期至渐新世晚期。 2）在测井剖面的大多数海洋层段中连续出现了化石甲藻包囊，这些组合总体上是多种多样的，包括Gla … More phyrocysta、Spiniferites、Homotryblium、Cordosphaeridium、Hystrichokolpoma、Heteraulacacysta、Deflandrea等属。、Dracodinium 和 Wetzeliella 表现出明显的地层变化，这对可行是有利的。此外，该组合的成分与东海同期沉积物的成分大多相同，但同时又与北海道的成分有很大不同。 -萨哈林地区。这支持了太平洋西北海岸的古生物地理分异，这种分异可能在始新世末期变得明显，这需要高纬度地区的独立生物地层学方案。 3）我们对软体动物化石的调查表明，佐世保群的组合应归属于芦屋动物群，缺乏角之泽动物群的典型元素，这意味着佐世保安阶段的年龄范围不应向上延伸。到中新世。