- Source: Toyora Group
The Toyora Group is one of the Mesozoic strata in Japan, and was originally named Toyoura Series (or Formation) by Hisakatsu Yabe in 1920. The present name was defined by Tatsuro Matsumoto in 1949.
It is the Lower-Upper Jurassic sediments in the East Asian continental margin that distributes in the eastern part of the Shimonoseki, Yamaguchi Prefecture, southwest Japan. The distribution of the Toyora Group extends north and south, and has been separated between north and south districts by the Tabe Basin and the Kikugawa Fault that is an active left-lateral strike-slip fault.
Geology
The Toyora Group is 1,000 to 2,000 metres (3,300 to 6,600 ft) thick, and divided into the Higashinagano, Nishinakayama, Utano, and Ohchi Formations in ascending order. The group rests unconformably on the tilted Paleozoic Renge Metamorphic Rocks and Toyohigashi Group, formations assigned to the Akiyoshi Belt. The Toyora Group is separated by a parallel or locally angular unconformity with the Latest Jurassic to Early Cretaceous Toyonishi Group.
The Toyora Group sediments are composed mainly of black mudstone, sandy mudstone, sandstone, conglomerate that deposited in a shallow marine embayment. The mudstone and very fine-grained sandstone beds are often bioturbated by an ichnogenus Phycosiphon.
See also
Toarcian turnover
Toarcian formations
Fernie Formation, Alberta and British Columbia
Whiteaves Formation, British Columbia
Navajo Sandstone, Utah
Whitby Mudstone, England
Posidonia Shale, Lagerstätte in Germany
Ciechocinek Formation, Germany and Poland
Lava Formation, Lithuania
Marne di Monte Serrone, Italy
Calcare di Sogno
Toundoute Continental Series, North Africa
Los Molles Formation, Argentina
Mawson Formation, Antarctica
Kandreho Formation, Madagascar
Kota Formation, India
Cattamarra Coal Measures, Australia
References
Kata Kunci Pencarian:
- Toyora Group
- Toyonishi Group
- Pentacrinites
- Cleviceras
- 2024 All Japan High School Soccer Tournament prefectural qualifiers
- Toarcian Oceanic Anoxic Event
