四国秩父帯の白亜系 : 下部白亜系の横ずれ断層について

概要

論文の詳細を見る
The Cretaceous System of the Chichibu Belt in Shikoku was divided into the Lower Cretaceous "Monobegawa Group" and the Upper Cretaceous Sotoizumi Group. The "Monobegawa Group" is further divided into the Monobegawa Group (emend.) and the Nankai Group (new name) because of the difference in their characteristic lithology and bivalve faunas between them. The distinction between the Monobegawa and Nankai Groups is one of the important clues to testify the presence of the Early Cretaceous lateral fault in the Chichibu Belt. The lateral fault which probably developed during the Hauterivian (or older) to Albian is recognized as the so-called "Kurosegawa Tectonic Belt". The Monobegawa Group is generally distributed on the northern side of the fault and uncomformably lies over the so-called "Northern Paleozoic Chichibu Belt". The Nankai Group is distributed sporadically on the southern side of the fault and very often accompanied by the "Jurassic" Torinosu Group, or is in fault with the so-called "Middle Paleozoic Chichibu Belt". The offset by the lateral fault is by considerable, several hundred kilometers or more. The Lower Cretaceous strata in the Shimanto Belt (Shinjogawa Group) are closely related to the Nankai Group in their characteristic lithology and common bivalve fossils. The summarized outline of the historical development of the Cretaceous System in Shikoku is illustrated in Fig.7.
日本古生物学会の論文
1985-06-11