中国东北地区航磁特征及居里面分析

中国东北地区位于西伯利亚和华北地块之间,中、新生代本区受西太平洋板块俯冲的影响,由于多期构造作用,导致地质构造形态极为复杂.本文通过分析航磁异常场,认识研究区的构造特征,并利用航磁异常数据的功率谱法反演居里等温面.航磁异常场和居里面分布特征均揭示研究区地质构造发展具有继承性;通过居里面起伏变化特征,并结合满-绥地学断面、及与大地热流分布的关系,讨论研究区地壳的热结构状态特点,结果显示居里面起伏趋势与软流圈起伏具明显的相关性;结合地震活动和地震层析成像研究,探讨了太平洋板块俯冲受阻引起岩浆和火山活动,进而导致居里面上隆的影响机制.

A characteristic analysis of aeromagnetic anomalies and Curie point isotherms in Northeast China

The Northeast China block lies among the Siberia,North China block and the west Pacific plate,along with complex geological features derived from episodic tectonics.In this paper,we analyzed aeromagnetic anomalies of Northeast China to recognize its characteristics related to the tectonics,and then used magnetic anomaly data to calculate the Curie point depth with the method of power-density spectrum analysis.Characteristics of both aeromagnetic anomalies and Curie point isotherm distribution indicate the inheritance in tectonic evolution.Compared with the heat flow distribution and Man-Sui Global Geoscience Transect(GGT),Curie point isotherms are used to discuss the thermal state of crust in study region,the result shows the close relationship between fluctuation of the Curie point isotherm and that of the asthenosphere.Based on earthquake activities feature and seismic tomography results,here we infer that the uplift of the Curie point isotherm of study region was due to the stagnancy of the subducting Pacific plate beneath northeast Asia,which also accounts for the magmatism and volcanism there.