Analysis of sedimentary environment of the upper Cenozoic in Niigata Sedimentary Basin

点击翻译按钮获取中文摘要

The Folded and thick Cenozoic sequence is distributed in the Niigata Sedimentary Basin. On the bases of stratigraphy reinvestigated, the sedimentary environment of the Cenozoic sequence was analyzed from the lithofacies and biofacies.The following results are important stratigraphically. 1) Higashi-Kubiki district: The Upper Miocene to Pleiocene Tamugigawa Formation, mainly composed of turbidite sediments, is interfingerred with the Shobudani Formation, mainly composed of massive mudstone.2) Nishi-Kubiki - Otari district: The Tenguhara-yama Volcanic Clasts, considerred to be correlated to the Nanatani Formation, is intercalated within the middle part of the Nambayama Formation correlated with the Nanatani to Lower Teradomari Formations.For the sedimentary environment, the following resilts are important.1) In Higashi-Kubiki district, the differentiation of sedimentary basin and the supply of coarse clastics from the provinance uplifted were taken place from the late Miocene to Pleiocene time. The basin was composed of the trough-type basin and horst.2) Formative process of Arahama Sand Dune in the Kashiwazaki district are investigated based on the sedimentary structure and textural property. The textural propertiy of sand of paleo-sand dune shows the characteristics of sand transported by wind same as the Holocene sand dune.3) Argonautidae, Dephalopoda from the type locality of Teradomari Formation is the first occurrence in the Niigata Sedimentary Basin. The occurrence is particulary important to the consideration of the paleo-oceanic environment, that is, the inflow of the warm current.