Discovery of a mylonite Zone (Ringou Mylonite Zone) in Nanyo City, Yamagata Prefecture and the northern extension of the Tanagura Tectonic Line.

Timing of mylonitization in the Nihonkoku Mylonite Zone of north Central Japan: Implications for Cretaceous to Paleogene sinistral ductile deformation in the Japanese Islands

“…As for the Oisawa Fault, the formative age was after Miocene and pre-Neogene basement rocks situated on both sides of the Oisawa Fault are similar in petrographical features (Kubo and Takahashi, 1992). Also, the granitic rocks on both sides of the Ringou Mylonite Zone are similar in petrography (Takiguchi and Tanaka, 2001). Therefore, at present, we regard the concealed fault to the east of the Asahi Mountains as the most possible northern extension of the TTL.…”

“…1). The Nihonkoku-Miomote Tectonic Line (NMTL) (Shimazu, 1964a), a major fault within the NihonkokuMiomote Mylonite Zone (NMMZ; Takahashi, 1999), is regarded as a possible northern extension of the TTL, along with the ''Oisawa Fault'' (Minakawa et al, 1967) and the Ringou Mylonite Zone (Takiguchi and Tanaka, 2001), which strike along the eastern margin of the Asahi Mountains, and a concealed fault to the east of the Asahi Mountains (Takahashi, 1999) (Fig. 1).…”