南海磁场特征研究

建立客观的磁力ΔT异常，获得可信的磁力ΔZ_⊥异常、居里面成果， 在此基础上开展综合地质地球物理研究，对于解决南海资源等相关的地质、地球物理问题意义重大.本文汇集我国历年在南海取得的磁力实测资料，重新处理、校正、整合，特别是追溯南海周边的国际地磁台的日变资料进行日变改正，形成的南海磁力ΔT异常，其资料品质得到了极大提高.采用全磁纬变倾角化极技术，获得磁力ΔZ_⊥异常，其与实测证实的磁性海山、海岛有非常好的匹配关系，建立起可以直接用于反演处理解释的南海磁力ΔZ_⊥异常.选择磁力ΔZ_⊥异常的小波多尺度分解四阶逼近，采用单一磁性界面反演技术进行深度反演，获得居里面又称磁性底界面.建立了认识、解释南海的磁场基础体系，证实了南海基性岩浆岩分布区与磁力ΔZ_⊥异常的正磁异常高密切相关，区域性的磁力ΔZ_⊥异常负磁异常区可能与居里面深度相关.

Characteristics of the Geomagnetic Field in the South China Sea

It is a major task to establish objective total magnetic anomaly △T and obtain credible △Z⊥ magnetic anomaly and Curie point isotherms.On this basis,we carry out comprehensive geological and geophysical studies of the South China Sea.It is of great significance in solving the relevant geological,geophysical and other issues resources in this region.We have has collected the measured data of the South China Sea in past years,re-processed, calibrated and integrated these date to form the total magnetic anomaly △T of the South China Sea.In particular we searched the diurnal variation data of international geomagnetic stations around the South China Sea,improved △T data quality greatly,and updated the total magnetic anomaly △T field of the South China Sea.We have obtained vertical component of △Z⊥ anomalies by using all-magnetic latitude variable inclination reduction to the Dole of magnetic anomaly technology.There is a very good match between △Z⊥ and magnetic seamounts and magnetic islands which have been confirmed,and then we established the magnetic field vertical component △Z⊥ field of South China Sea that can be directly used for inversion processing and interpretation.We selected the pole magnetic anomaly of wavelet multi-scale decomposition of fourth-order approximation,using a single magnetic interface inversion technology to inversion of the depth and obtained the Curie point isotherms known as the magnetic bottom interface. We have established a basic system to study and explain the magnetic field of the South China Sea, confirmed that the distribution of basalt areas of the South China Sea is correlated with the high magnetic anomalies and the regional negative magnetic anomaly area may be related to the depth of Curie point isotherms.