Statistical Analysis of the Geologic Column Data of the Cretaceous Izumi Group, Central Japan, with Special Reference to the Sedimentation Model

Abstract

Three deterministic sedimentation models are defined to analyze the geologic column data of the Upper Cretaceous Izumi Group, central Japan. Those are the constant deposition model in which all lithologies which compose the column have the same rate of sedimentation, the mixed deposion model in which a specific lithology was deposited at a constant rate while the rates of sedimentation of the other lithologies changed in the course of deposition, and the periodic deposition model in which a specific lithology was deposited periodically. According to the models, the geologic column data are transformed into serial data which can be treated as time series data. Formulations of the three models and the interrelationships among the three series are discussed. Five columns are treated, and the chi-square test, t test, correlation analysis and time series analysis are adopted to examine the chosen model for the Izumi Group on the basis of information from the field. Consequently some inconsistencies are detected in one of analyzed columns, and they may be the reflection of the specific sedimentation condition.