On the Nappe Theory with Reference to the Northern Part of the Kanto Mountainland

Abstract

H. FUJIMOTO (1937) stated as follows : 1) in the north-eastern part of the Kanto Mountainland, the Nagatoro Formation of the Ogiri-yama which consists mainly of metamorphic green schist forms the nappe which moved from the north upon the Chichibu Paleozoic Formation, and 2) the Chichibu Formation in the neighborhood of Yasudo, which exists in the Ogiri-yama nappe, makes up a fenster, while the Chichibu Formations in the neighborhood of Dodaira-yama, Otakatori-yama and in other regions form klippes derived from the nappe which moved from the north over again upon the Ogiriyama nappe. Furthermore, FUJIMOTO and others (1943) stated that in the northern part of the Kanto Mountainland the Atokura Formation (Cretaceous) forms klippes derived from the nappe which moved from the northeast upon the Nagatoro metamorphic terrain and the Chichibu Paleozoic Formation.In this paper the writer tries to make a general review of the opposite or affirmative studies by many geologists on the nappe theory by FUJIMOTO. On the “Ogiri-yama nappe”, the writer supports the SEKI's view which opposes to the one held by FUJIMOTO. The Chichibu Formations in the neighborhood of Yasudo, Dodaira-yama, Otakatoriyama and others do not form a fenster or klippes, but overlied conformably upon the Nagatoro Formation and later isolated from each other by erosion. On the “Atokura klippes”, the writer considers that the Atokura Formation does not form klippes but consists of autochthonous sedimentary rocks, because some of the contact planes between the Atokura Formation and the Nagatoro metamorphic rocks dip to the north, and the Nagatoro metamorphic rocks occur in the hanging wall.