Senmatsu Fm
Type Locality and Naming
Toyoma(Okago); North Kesennuma; South Kesennuma; Utatsu districts
Synonym:
Lithology and Thickness
Compared to the Lower-Middle Permian successions of the South Kitakami Belt, these younger formations are lithologically monotonous and dominated by mudstone with minor sandstone and rare limestone and conglomerate. The mudstones of these strata typically show strong slaty cleavage, except for those in the Okago district, and so have been used as roofing slate.
[Figure 1: Stratigraphy of the Palaeozoic of the South Kitakatmi Belt, NE Japan (after M. Ehiro et al., 2016)]
Relationships and Distribution
Lower contact
Regionally, the schematic strat column indicates the next older unit as Okago Fm
Upper contact
Regionally, the schematic strat column indicates the next younger unit as Suenosaki Fm
Regional extent
Toyoma(Okago); North Kesennuma; South Kesennuma; Utatsu districts
GeoJSON
Fossils
The Senmatsu, Tanoura and Nabekoshiyama formations, as well as unnamed beds in the Ofunato district, contain Changhsingian fusulinoideans, smaller foraminifers and ammonoids (lshii et at., 1975; Tazawa 1975: Murata & Shimoyama 1979; Ehiro 1996; Kobayashi 2002).
Age
Depositional setting
Additional Information