基于米兰科维奇理论的高精度旋回识别与划分--以南图尔盖盆地Ary301井中侏罗统为例

将天文轨道周期与不同级别的旋回联系起来，旨在使米兰科维奇周期这一高精度时间标尺纳入高频层序地层划分中，实现高精度旋回的识别与划分。以哈萨克斯坦南图尔盖盆地Aryskum地堑Ary301井为例，基于不同沉积特征，分别对卡拉甘塞组I~IV段自然伽马测井数据进行频谱分析和连续小波变换，结果显示沉积地层中保存完好的米兰科维奇旋回，天文轨道周期对Aryskum地堑沉积过程具有明显影响，并将31.9~39.5 m旋回厚度解释为受400 kyr长偏心率周期控制，11.9~14.2 m，6.7~8.8 m旋回厚度分别受125 kyr和95 kyr短偏心率周期控制。对长、短偏心率周期进行滤波分析后，与天文模型理论周期曲线进行对比，建立卡拉甘塞组的浮动天文年代标尺，分别以400 kyr、125 kyr偏心率周期滤波曲线作为中期和短期旋回划分的参考曲线，共识别出11.5个中期旋回和47个短期旋回，为高频旋回划分提供了一种不受人为因素影响的天然标准，保证了研究区旋回划分的科学性和统一性。

Recognition and Division of High-resolution Sequences based on the Milankovitch Theory: A case study from the Middle Jurassic of Well Ary301 in the South Turgay Basin

It aims to achieve the division and correlation of high-resolution sequences by integrating the Milankovitch cycles with cycles of different scales so as to introduce such a high precision time scale into the high-resolution sequence stratigraphic classification.This work takes the Well Ary301 in Aryskum graben of the South Turgay Basin in Kazakhstan as an example.Based on different sedimentary characteristics, spectral analysis and continuous wavelet transform are used to Intervals I-IV of natural gamma ray data, respectively, which demonstrate that well-preserved Milankovitch cycles are contained in the sedimentary strata.Aryskum graben deposition process is obviously effected by astronomical orbital period, the formation thickness of 31.9~39.5 m is affected by the long eccentricity of 400 kyr, the formations thickness of 11.9~14.2 m and 6.7~8.8 m are affected by the short eccentricity of 125 kyr and 95 kyr, respectively.Cycle curves analyzed by filtering are compared with the astronomical model theory, which helps establish the Karagansky Formation of floating astronomical time scale.Finally, 11.5 middle term cycles and 47 short term cycles are identified, the filtering curves with eccentricity cycles of 400 kyr and 125 kyr are identified as the reference curves to divide middle term and short term cycles to ensure the scientific and unified division scheme in the study area, and a natural standard unaffected by man-made factors is proposed for high-frequency sequence division.