Permian Ammonoid Fauna of the Kitakami Massif, Northeast Japan — Biostratigraphy and Paleobiogeography

Masayuki Ehiro

pp. 113-122, in English

Abstract:

Biostratigraphy and paleobiogeography of Permian ammonoids from the Southern Kitakami Massif are studied. Four ammonoid zones, the Agathiceras (middle Sakamotozawan to lower Kanokuran), Timorites (uppermost lower Kanokuran to upper Kanokuran), Araxoceras (lower to middle Toyoman) and Neogeoceras kitakamiense (upper Toyoman) Zones, in ascending order are proposed. Based on the ammonoids and fusulinids, the Sakamotozawan, Kanokuran and Toyoman Series are correlated with the Sakmarian to Bolorian, Kubergandian to Midian (Abadehian) and Dzhulfian to Dorashamian intervals, respectively. During Permian time, four ammonoid provinces, namely the Boreal, Equatorial American, Equatorial Tethyan and Peri-Gondwanan Provinces are recognizable. The occurrences of Timorites, Cibolites and araxoceratid ammonoids suggest that the Southern Kitakami Massif, together with the Sikhote-Alin Block, had belonged to the Equatorial Tethyan Province adjoining the South China Block during Middle to Late Permian time.

Keywords: Permian, ammonoid fauna, biostratigraphy, paleobiogeography