岡山縣英田郡福本附近の中・古生層 : 舞鶴地帶の層序と構造(その1)

Abstract

The Upper Permian Kose group, the Lower and Middle Triassic Fukumoto group, the Upper Triassic Yanagi formation and Nakaiso conglomerate beds, the so-called Inkstone group, and basic intrusive rocks crop out in the vicinity of Fukumoto-mura in Okayama Prefecture., The Palaeozoic and Mesozoic formations in this district, together with the basic rocks, indicate that the "Maizuru Zone" extends into Okayama Prefecture about 130km., WSW of Maizuru in Kyoto Prefecture., The stratigraphy of the Palaeozoic and Triassic formations is shown in the following table., Norian?-Nakaiso conglomerate beds.,.,.,.,.,.,mainly conglomerate with sandstone, thickness 200m., unconformity? Carnian-Yanagi formation.,.,.,.,.,.,black shale and carbonaceous sandy shale, thickness 70m., fault Anisian-Miyano-oku formation.,.,.,.,.,.,dark blue calcareous sandy shale with shale and fine sandstone, thickness 300m., Kyogakubo formation.,.,.,.,.,.,alternation of shale and sandstone, thickness 270-300m., Scythian -Kusano formation.,.,.,.,.,.,mainly fine to medium sandstone with conglomerate, thickness 68-96m+., fault Upper Permian-Kose group.,.,.,.,.,.,mainly black shale with sandstone and conglomerate lens, thickness 350m -., The Kose group contains fusulinids such as Lepidolina, sp., and Yabeina, sp., and is correlated with the Upper Permian Kuma series in Kyushu., The Fukumoto group contains pelecypod-fossils such as Neobakevellia kanb i NAKAZAWA (MS.,), Myophoria, aff., laevigata, ALBERTI, Eumorphotis sp., nov, and "Pecten" sichoticus BITTNER, in the Kusano and Kyogakubo formations, and cephalopods such as Hollandites sp., "Danubites" sp., and Orthoceras sp., in the Miyano-oku formation., From these fossils the group is considered Scythian and Anisian in age., The group is in fault contact with the Kose group, but is supposed to overlie the Kose group unconformably., The Norian (?) Nakaiso conglomerate beds overlie the Kose and Fukumoto groups in angular unconformity as a result of a severe crustal movement of Ladinian or Carnian age.,