抄録
The Shiiya Age successions (6.0Ma to 3.5Ma), northren part of the Niigata oil fields are mainly consisted of radial-type submarine fan deposits. Using many seismic profiles and wells, we could detect five high sea-level events during the Shiiya Age, based on analysis of foraminiferal assemblages, and make clear that the deposition of the submarine fans are controlled by eustatic sea-level changes, under a stable tectonic environment of the back-arc basin of Japan Arc through the time.
The eustatic controls during the Shiiya Age are as follows:
1) the sand lobes of submarine fan mainly develop in a basin center at low sea-levels.
2) each sand lobe retreated gradually from a basin center to the margin with sea-level rise.
3) the successions of the submarine fan change upward from proximal to distal facies.
Those three things are fit well to the basic concepts of Mutti's (1985) model.
