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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第三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孢囊分析，（c）软体动物化石取样。已采伐的部分包括阿马库萨地区的下岛群、高岛地区的高岛群和尾岛群、崎户-松岛地区的松岛群和西曾野木群、佐世保地区的相浦群和佐世保群、加拉津地区的大内群和岸岛群、筑穗地区的芦屋群、鱼屋湾地区的日置群和三池地区的满田群。根据前人的研究，整个采样层段的年龄范围从始新世中期到渐新世晚期。2）在大部分海相层段中，连续出现了甲藻孢囊化石。组合，一般是多样的，包括属，如玻璃 ...更多信息 phyrocysta，Spiniferites，Homotryblium，Cordosphaeridium，Hystrichokolpoma，Heteraulacacysta，Deflandrea，Dracodinium和Wetzeliella。它们显示出明显的地层变化，这对日本西南部可行的生物地层潜力是积极的。初步划分了生物地层分带。此外，组合的成分大多是共同的，从同时代的沉积物在东海，虽然他们在同一时间从北海道-萨哈林地区有很大的不同。这支持了沿着太平洋西北海岸的古生物地理分化，这种分化可能在始新世末期变得明显，这需要高纬度和低纬度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，来自佐世保群的组合应归属于芦屋动物群，缺乏门之泽动物群的典型元素。这意味着佐世保阶的年龄范围不应该延伸到中新世。少