Late Paleocene–middle Miocene pelagic sequences in the Boso Peninsula, Japan: New light on northwest Pacific tectonics
1998; Wiley; Volume: 7; Issue: 3 Linguagem: Inglês
10.1111/j.1440-1738.1998.00191.x
ISSN1440-1738
AutoresMia Mohammad Mohiuddin, Yujiro Ogawa,
Tópico(s)Geological and Geophysical Studies
ResumoLate Paleocene–middle Miocene pelagic limestone/chert sequences from the Mineoka Tectonic Belt, Boso Peninsula, central Japan, were biostratigraphically studied for planktic foraminifer fossils for the first time. The rock units are included as several isolated blocks tectonically within the ophiolitic mélange together with the Mio‐Pliocene Honshu arc‐derived terrigenous and Izu Arc‐derived volcaniclastic materials. The pelagic sequences are grouped into the newly proposed Kamogawa Group which is subdivided into the Paleocene Nishi Formation, Eocene–Oligocene Heguri‐Naka Limestone and early–middle Miocene Shirataki and Heguri Formations. This study of Kamogawa Group pelagic sequences throws new light on tectonic modeling of plate accretion to the unique trench–trench–trench (TTT)‐type triple junction area off the Boso Peninsula. Different formations of the Kamogawa Group have different tectonic and paleogeographic significances for the oceanic plate with a seamount that was approaching the Izu and Honshu arcs during Pacific plate subduction, and that was accreted to the Honshu Arc during the middle Miocene.
Referência(s)