[MIS20-P03] 群馬県東部八王子丘陵の足尾テレーンから産出したペルム紀放散虫（予報）
キーワード：ペルム紀放散虫、足尾テレーン、ジュラ紀付加体、八王子丘陵、群馬県
The Ashio terrane, a Jurassic accretionary complex, is distributed over the Ashio Mountains in the North Kanto region, central Japan. Hachioji Hills in eastern Gunma Prefecture is located at the southwest end of the Ashio Mountains, and the Ashio terrane is exposed at the hills. However, there is a few studies that focus on the Ashio terrane in Hachioji Hills. I have surveyed the Ashio terrane in the Ashio Mountains, including that in Hachioji Hills, since 2016.
I discovered Permian radiolarian assemblages from red bedded cherts of the Ashio terrane in Hachioji Hills. Previously, Middle Jurassic radiolarians occurred in the mudstones of Ashio terrane in Hachioji Hills; however, Permian radiolarian occurrences have never been reported from Hachioji Hills.
The assemblages contain Pseudoalbaillella sakmarensis Kozur. This species occurred in the Pseudoalbaillella lomentaria Assemblage Zone and Albaillella sinuata Range Zone of the middle Cisuralian, lower Permian.
The Ashio terrane in Hachioji Hills has been considered to be extension of the Kiryu-Kurohone Unit distributed over the Kiryu and Kurohone areas. However, the Kiryu-Kurohone Unit contain no Permian cherts according to the previous studies. Our result suggests that the Ashio terrane in Hachioji Hills belongs to other unit in the Ashio Mountains.
I discovered Permian radiolarian assemblages from red bedded cherts of the Ashio terrane in Hachioji Hills. Previously, Middle Jurassic radiolarians occurred in the mudstones of Ashio terrane in Hachioji Hills; however, Permian radiolarian occurrences have never been reported from Hachioji Hills.
The assemblages contain Pseudoalbaillella sakmarensis Kozur. This species occurred in the Pseudoalbaillella lomentaria Assemblage Zone and Albaillella sinuata Range Zone of the middle Cisuralian, lower Permian.
The Ashio terrane in Hachioji Hills has been considered to be extension of the Kiryu-Kurohone Unit distributed over the Kiryu and Kurohone areas. However, the Kiryu-Kurohone Unit contain no Permian cherts according to the previous studies. Our result suggests that the Ashio terrane in Hachioji Hills belongs to other unit in the Ashio Mountains.