LATE PERMIAN (LOPINGIAN) FORAMINIFERS FROM THE TSUKUMI LIMESTONE, SOUTHERN CHICHIBU TERRANE OF EASTERN KYUSHU, JAPAN
LATE PERMIAN (LOPINGIAN) FORAMINIFERS FROM THE TSUKUMI LIMESTONE, SOUTHERN CHICHIBU TERRANE OF EASTERN KYUSHU, JAPAN
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DOI：
10.2113/gsjfr.43.2.154
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发表时间：
2013-04
影响因子：
1.1
通讯作者：
F. Kobayashi
中科院分区：
文献类型：
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作者：
F. Kobayashi
自40年前在日本西南秩父地体南部的筑美灰岩中发现二叠纪最新的竹丝藻属和早三叠世双壳类以来，该地层的二叠纪-三叠纪界线问题一直备受关注。本文表明，筑美灰岩的上二叠统（乐平阶）部分1）整体上强烈破碎，2）或多或少的结晶和重结晶，3）构造上夹有中二叠统（Capitanian）灰岩楔，4）与可能的三叠纪碳酸盐断层接触。晚二叠世有孔虫动物群由37个分类单元组成，其中包括6属7种，其中包括新的Staffellid属和种Tsunjiellatsunjiensis。有Codonofusiella kwangsiana的样品被确定为Wuchiapingian，而其他没有这个物种的样品则是不确定的Wuchiapingian或Changhsingian年龄。虽然没有发现Palaeofusulina，但筑美包含了第一个已知的产自二叠纪石灰岩的Colaniella，该石灰岩嵌在环太平洋的侏罗纪-白垩纪地层中。筑美石灰岩中晚二叠世有孔虫动物群对于理解晚二叠世大陆和海山石灰岩块的动物区系和板块运动具有重要的古生物地理学和构造学意义，沿着日本西南部高千穗和白川-野村地区的同时代动物群。
Permian-Triassic boundary problems in the Tsukumi Limestone, Southern Chichibu Terrane, SW Japan, have been of special interest since the discovery in this unit of the latest Permian fusuline genus “ Palaeofusulina ” and Early Triassic bivalves about 40 years ago. This paper shows that the Upper Permian (Lopingian) part of the Tsukumi Limestone is 1) strongly fractured as a whole, 2) more or less dolomitized and recrystallized, 3) tectonically interposed by Middle Permian (Capitanian) limestone wedges, and 4) in fault contact with probable Triassic carbonates. The Late Permian foraminiferal fauna consists of 37 taxa, of which six genera and seven species are fusulines, including the new staffellid genus and species, Tsukumiella tsukumiensis . Samples with Codonofusiella kwangsiana are assigned with certainty to the Wuchiapingian, whereas others without this species are of indeterminate Wuchiapingian or Changhsingian age. Although Palaeofusulina was not found, the Tsukumi contains the first known occurrence of Colaniella from Permian limestone imbedded in Jurassic–Cretaceous terranes of the circum-Pacific. The Late Permian foraminiferal fauna of the Tsukumi Limestone is paleobiogeographically and tectonically important for understanding the faunal provincialism and plate movement of continental and seamount limestone blocks in the Late Permian, along with the coeval faunas of the Takachiho and Shirokawa-Nomura areas in SW Japan.