Upper Sorachi Gr
Period:
Cretaceous
Age Interval:
Province:
Hokkaido
Type Locality and Naming
Sorachi-Yezo Belt (Yezo Main Zone)
Synonym:
Lithology and Thickness
The upper Sorachi Group is characterized by siliceous and volcanogenic sedimentary rocks such as chert, siliceous mudstone, felsic tuff and volcanic sandstone and conglomerate, with occasionally intercalated basaltic pillow lavas, dolerite sills (Kito 1987; Niida 1992), felsic tuff breccia and quartz diorite dykes (Girard et al. 1991).
Lithology Pattern:
Volcanic_ash
Relationships and Distribution
Lower contact
Lower Sorachi Gr (conformable)
Upper contact
Lower Yezo Gr (conformable)
Regional extent
Sorachi-Yezo Belt (Yezo Main Zone)
GeoJSON
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Fossils
Siliceous sedimentary rocks yield Late Jurassic-middle Early Cretaceous radiolarians (e.g., Kanie et al. 1981; Kiminami et al. 1985a, b; Kito 1987, 1995, 1997; Takashima et al. 2001).
Age
Age Span:
Beginning stage:
Berriasian
Fraction up in beginning stage:
0
Beginning date (Ma):
143.10
Ending stage:
Barremian
Fraction up in the ending stage:
0
Ending date (Ma):
126.50
Depositional setting
Lavas and volcanic rock clasts of the upper Sorachi Group show chemical characteristics of an arc setting (Girard et al. 1991; Niida 1992; Takashima et al. 2002).
Depositional pattern:  
Additional Information
Compiler:
Hayato Ueda. 2g Hokkaido. in Moreno, T., WALLIS, S., Kojima, T. & Gibbons, W. (Eds) 2016. The Geology of Japan. Geological Society. London. 201-220.