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柴达木三湖地区七个泉组地层旋回性明显,且具有高频旋回的特点。应用连续小波时频和快速傅里叶频谱分析方法分别对该地层的自然伽马曲线进行了分析,并对小波分析和傅里叶分析在米氏旋回中的识别及其优缺点进行了探讨。结果表明,小波分析和傅里叶分析在米氏旋回识别中得到的地层旋回厚度比与米兰科维奇周期比十分接近,高频旋回由米兰科维奇气候旋回控制。其中偏心率周期控制的地层旋回平均厚度为12.93m;地轴倾角长、短周期控制的地层旋回平均厚度分别为6.32,5.00m;岁差长、短周期控制的地层旋回平均厚度分别为2.78,2.34m。高频旋回的沉积速率约为0.13m/ka。小波时频分析和傅里叶频谱分析可以互为补充,联合应用能更准确地识别米氏旋回。
The Qijuquan Formation in the Qahu area of the Qaidam has obvious swirling characteristics and high-frequency cycle characteristics. The natural gamma curves of this stratum are analyzed by using continuous wavelet time-frequency and fast Fourier spectral analysis respectively. The recognition of wavelet analysis and Fourier analysis in Mie cycles and its advantages and disadvantages are also discussed. The results show that the thickness ratio of stratigraphic cycle obtained by the wavelet analysis and Fourier analysis is very close to the Milankovitch cycle ratio and the high frequency cycle is controlled by the Milankovitch climate. Among them, the mean cycle-controlled stratigraphic cycle average thickness is 12.93m. The stratigraphic average thickness of long-period and short-cycle control is 6.32 and 5.00m respectively. The stratigraphic average thickness of short-period and long-period control is 2.78 and 2.34m . The deposition rate of high-frequency cycle is about 0.13m / ka. Wavelet time-frequency analysis and Fourier spectrum analysis can complement each other, combined application can more accurately identify Mie cycles.