Identification and characterization of a subsided barrier island in the Holocene alluvial plain, Niigata, central Japan

摘要

The Echigo Plain in the Niigata area of central Japan is a coastal alluvial plain facing the Sea of Japan. The Plain contains several rows of coastal sand dunes. During the Holocene maximum transgression, a barrier island sand body was formed on the plain. However, the distribution of this barrier island is partially intermittent. Based on facies analysis of cores, the barrier island succession was found to be buried by alluvium in the central part of the Echigo Plain. The barrier sand bodies do occur in the central part of the Echigo Plain, but they are deeply subsided and tilted by an active fault in the western margin of the plain. The alluvium in this area records a history of subsidence and changes in the depositional system due to the movements on the active fault.