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提出根据区域重力异常计算地壳表层视密度分布的方法。依据原观测平面异常与延拓到某一高度平面异常的差值场所具有的突出浅源异常、压制深源异常的特点 ,按维纳滤波原理 ,应用多层格林等效层模型精确模拟该差值重力场的径向对数功率谱 ,设计重力场在频率域进行异常分离的具有自适应性的优选延拓算子 ,实现垂向异常分离。利用重力场可看成由许多等效直立棱柱体叠加的原理 ,在频率域内 ,通过换算重力场的一次导数 ,计算出视密度的分布。用上述方法处理中国布格重力异常图 ,获得了中国地壳表层 0 10km剩余重力异常 ,并成功编制视密度图。比较表明 ,视密度的分布特征与大地构造单元及分区有较好的对应关系。地壳表层的岩石密度分布的获得 ,为中国的基础地质与构造研究提供了重要依据。
A method to calculate the apparent density distribution of the crust surface based on regional gravity anomalies is proposed. Based on Wiener filtering principle, a multi-layer Green's equivalent model is used to accurately simulate the difference between the original observation plane anomalies and the extension of the difference to a certain height plane anomalies with shallow anomalies and the suppression of deep anomalies. The radial logarithmic power spectrum of the value gravitational field is used to design the adaptive continuation operator with optimal gravity field in the frequency domain to realize the vertical anomaly separation. The use of the gravitational field can be seen as the principle of superposition of many equivalent upright prisms in the frequency domain by calculating the first derivative of the gravitational field to calculate the apparent density distribution. Using the above method to deal with the Bouguer gravity anomaly in China, the residual gravity anomalies of 0 10 km above the crust in China were obtained and the apparent density maps were successfully compiled. The comparison shows that the distribution of apparent density has a good correspondence with the tectonic units and zoning of the earth. The acquisition of rock density distribution on the crust surface provides an important basis for the study of the basic geology and tectonics in China.