Upper part of the oceanic plate stratigraphy of the Jurassic accretionary complex (an example) @Oceanic plate stratigraphy shows a travel history of an oceanic plate from mid oceanic ridge to trench. Although the initial stratigraphy of the sediments on the oceanic plate is lost by deformation during the accretionary process, the stratigraphy consisting of basalt, limestone, chert, siliceous mudstone, and mudstone and sandstone in ascending order can be reconstructed. Radiolarians play an important role in the age determination of each rock type. To reconstruct the oceanic plate stratigraphy is important in examination of tectonic history and in broad correlation. All following radiolarians were obtained from the Chichibu Belt in the Toyohashi area; 1: Archicapsa ? pachyderma (Tan), 2: Laxtorum ? jurassicum Isozaki et Matsuda, 3: Tricolocapsa plicarum Yao, and 4: Tricolocapsa conexa Matsuoka. All scale bars indicate 100 ƒÊm. |