东海陆架盆地下第三系高频层序分析

Analysis of Paleogene High-Frequency Sequences in the East China Sea Shelf Basin

本文提出了进行高频层序分析的新思路和方法。根据米兰科维奇周期理论,利用自然伽玛测井曲线,采取傅立叶交换将曲线的量值域转换为频率域。分析每一个峰值频率的波长及其相互之间的比率关系,寻找那些波长比率与地史时期气候变化的旋回周期比率相同或相似的频率,从而捕获高频旋回信息。东海陆架盆地下第三系进一步细划出38个四级层序。利用捕获的米兰科维奇周期信息,进一步计算了高频层序沉积持续的时间和沉积速率。

This paper puts forward a new method for the analysis of high-frequency sequences. Based on the Mi-lankovitch Cycle and gamma-ray log, the quantitative field can be transformed into the frequency field of the log by the Fourier transform. The wavelength of every peak frequency and the ratios between these wavelengths are analyzed in order to find the frequencies whose wavelength ratios are the same as or similar to the cycles of the geological time. The Eocene is subdivided into 38 fourth-order sequences. Moreover, the persistent deposi-tional time and depositional rate of the high-frequency sequences are estimated based upon the information of the Milankovitch Cycle captured in the analysis.