四国四万十帯北帯の鳥巣式石灰岩ブロックから産する後期ジュラ紀放散虫とその意義

概要

論文の詳細を見る
Well-preserved Late Jurassic radiolarians are recovered from allochtho-nous blocks of the Torinosu-type limestone embedded in the Early Cretaceous Hinodani Formation, northern Subbelt of the Shimanto Terrane, Shikoku. Based on the faunal composition, this radiolarian fauna is assigned to that of Late Jurassic Tithonian. The Torinosu-type limestone which contains this radiolarian fauna was deposited as marginal reef or shelf margin carbonates on the accreted Togano Group or its equivalents. The radiolarians were captured in ooid grainstone and bioclast wackestone and fossilized under the peculiarly suitable condition for preservation. Radiolarian-bearing limestones deposited on the reef or carbonate mound show certain sedimentary sequences and biofacies. These limestones intercalated in the Torinosu Group or its equivalents were deposited on the continental shelf or slope and emplaced as one of the constituents of olistostrome in the Hinodani Formation by submarine slidings in late Early Cretaceous time.
社団法人東京地学協会の論文
1996-02-25