Revision of Early Spathian (Late Olenekian, Early Triassic) Ammonoids from the Osawa Formation at Akaushi in the Motoyoshi Area, South Kitakami Belt, Northeast Japan
Revision of Early Spathian (Late Olenekian, Early Triassic) Ammonoids from the Osawa Formation at Akaushi in the Motoyoshi Area, South Kitakami Belt, Northeast Japan
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DOI：
10.2517/pr210003
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发表时间：
2022-08
影响因子：
0.9
通讯作者：
Y. Shigeta
中科院分区：
文献类型：
--
作者：
Y. Shigeta
抽象的。对元代地区Akaushi的Asawa组以前报道的菊石组合进行了分类修订，即Columbites parisianus、亚柱bites perrinismithi和Eophyllites cf。Inopinatus、Neocolumbites gram mi、N.insignis、Probelbites ussuriens和P.subquatus的分类结果。此外，这一动物群还包括杜威威氏菌。由于这些菊石是俄罗斯远东南滨海的N.Insignis带的特征，所以大泽组的最低部分与下斯巴山(上奥伦基统，下三叠统)的上部明显相关，动物群的相似性表明南北上带可能位于Panthalassa西侧的South Primorye附近。
Abstract. A taxonomic revision of the ammonoid assemblage previously reported from the Osawa Formation at Akaushi in the Motoyoshi area, i.e., Columbites parisianus, Subcolumbites perrinismithi and Eophyllites cf. dieneri, leads to the conclusion that the fauna should be attributed to Hellenites tchernyschewiensis, H. inopinatus, Neocolumbites grammi, N. insignis, Procolumbites ussuriensis and P. subquadratus. In addition, this fauna also includes Deweveria kovalenkoi. Because these ammonoids are characteristic of the N. insignis Zone of South Primorye, Russian Far East, the lowest part of the Osawa Formation clearly correlates with the upper part of the lower Spathian (upper Olenekian, Lower Triassic), and the faunal similarity suggests that the South Kitakami Belt may have been located near South Primorye on the western side of the Panthalassa.