【摘要】 自然伽马曲线包含丰富的地质信息,能够很好地反映由气候变化引起的地层旋回。采用频谱分析对鄂尔多斯盆地陇东地区延安组湖沼相自然伽马测井曲线进行反演,可以得出地层中很好地保存了高频的米兰科维奇旋回,认为研究区延安组地层中的沉积旋回主要受古气候变化的控制,其中偏心率周期引起的地层旋回厚度变化范围为7.86～16.75m;地轴倾角周期引起的地层旋回厚度变化范围为2.34～6.36m;岁差周期引起的地层旋回厚度变化范围为1.14～2.96m。频谱分析法可用于测井曲线进行高频沉积旋回分析。更多还原

【Abstract】 Natural gamma\|ray well log that include a great amount of geological information can well reflect stratigraphic cycles caused by climate changes. In this paper, the authors use frequency spectral analysis method to analyze the gamma-ray curves of liminetic facies of Yan’an Formation in Longdong area, Ordos Basin and find out that the strata conserve well Milankovitch cycles and the main sedimentary cycles are 123, 46.8, 36.7, 21.8 and 17.9 ka, corresponding with the eccentricity cycle, the obliquity cycle and the precession cycle of Milankovitch cycle. So it is reasonable to deduce that the sedimentary cycles are (controlled) by palaeoclimate which is caused by the eccentricity cycle, the obliquity cycle and the precession cycle. The thickness range of sedimentary cycles caused by the eccentricity cycle is 7.86～16.75 m, that caused by the obliquity cycle is 2.34～6.36 m and that caused by the precession cycle is 14～2.96 m. (Frequency) spectral analysis can be used to study the high frequency with well log.更多还原