论文部分内容阅读
建立了一个分离中、低频重力场的数学模型。根据南沙群岛地质构造的特征，选择4条具有代表性的重力测线N2，N9，N10和N11的自由空间重力异常，进行福里哀频谱值的计算并研究振幅谱值的分布规律，确定61.44km为4条重力测线的低频和中频重力场的临界值；设计分开低频和中频重力场的分离因子，分离出4条重力剖面的低频和中频重力异常；进而分析其低频和中频重力异常的特征。结果表明：N2和N11频谱值的分布带窄，低频重力场显著，中频重力场不显著；N9和N10的频谱值分布带宽，中频和低频重力场均显著。分析了它们和地质构造的关系。曾母盆地、南华盆地和南薇盆地的低频重力异常和沉积厚度成反关系，其余地区成正关系。
A mathematical model of mid-low frequency gravitational field is established. According to the geological structure of Nansha Islands, the free gravity gravity anomalies of four representative gravity lines N2, N9, N10 and N11 are selected to calculate the spectral values of Fraser and to study the distribution rule of the amplitude spectral values, and to determine the spatial distribution of 61.44km As the cutoff value of the low-frequency and intermediate-frequency gravitational fields for the four gravimetric surveys. The separation factor for separating the low-frequency and intermediate-frequency gravitational fields is designed to separate the low-frequency and intermediate-frequency gravity anomalies of the four gravity profiles. . The results show that the spectral distributions of N2 and N11 are narrow, the low-frequency gravitational field is significant, and the intermediate-frequency gravimetric field is not significant. The spectral distributions of N9 and N10 are significant, and the intermediate and low-frequency gravitational fields are significant. Analyzed their relationship with the geological structure. The low-frequency gravity anomalies in Zengmu, Nanhua and Nanwei basins are inversely related to the sedimentary thickness, and the rest are in a positive relationship.