陆丰凹陷韩江组旋回地层学分析及天文年代标尺的建立

珠江口盆地为新生代典型的海相盆地，也是我国重要的海上油气生产基地。前期已有很多学者对珠江口盆地的地层划分与对比开展了研究，但研究的精度不够。为了提高珠江口盆地陆丰凹陷韩江组地层划分与对比的精度，选择珠江口盆地陆丰凹陷A、B井韩江组的自然伽马数据序列作为古气候替代性指标，使用频谱分析、滤波等方法进行旋回地层学分析。通过深度域频谱分析和小波分析认为，该套地层中保存了米兰科维奇旋回信号，且主要受405 ka长偏心率周期的影响。利用稳定的405 ka长偏心率周期进行天文调谐，结合古生物地层年代框架，建立起陆丰凹陷“绝对”天文年代标尺；结合碳氧同位素变化曲线，估算出2次碳同位素负漂移和1次碳同位素正向偏移事件的持续时间；利用天文旋回周期计算出陆丰凹陷韩江组的沉积速率，发现沉积速率的变化与海平面变化具有相关性。

Cyclical stratigraphic analysis and establishment of astronomical chronograph of Hanjiang Formation in Lufeng Sag

As a typical Cenozoic Marine basin, the Pearl River Mouth Basin is also an important offshore oil and gas production base in China. Many scholars have studied the stratigraphic division and correlation of the Pearl River Mouth Basin, but the research accuracy is not enough. In order to improve the accuracy of stratigraphic division and correlation of Hanjiang Formation in Lufeng Sag, Pearl River Mouth Basin, the natural gamma ray data series of Hanjiang Formation in Well A and Well B in Lufeng Sag were selected as paleoclimate surrogate indexes, and the cyclic stratigraphy was analyzed by spectral analysis and filtering methods. Through depth domain spectral analysis and wavelet analysis, it is identified that Milankovich cycle is preserved in the formation, and it is mainly affected by the 405 ka long eccentricity period. Using the stable 405 ka long eccentricity period for astronomical tuning, combined with the paleontological stratigraphic dating frame, the absolute astronomical dating scale of Lufeng Depression was established. Combined with the carbon and oxygen isotope change curves, the duration of two carbon isotope negative shift events and one positive shift event was estimated. Using the sedimentation rate calculated by astronomical cycle, it is found that the change of sedimentation rate is correlated with the change of sea level.