基于MF6, EMM2010和CGRF2010模型的中国大陆地壳磁异常特征

Crustal magnetic anomaly characteristics of Chinese mainland based on MF6, EMM2010 and CGRF2010 models

  • 摘要: 利用地磁场全球模型MF6, EMM2010和基于地面观测数据建立的2010.0中国地磁参考场(CGRF2010)等3个模型分别计算了中国大陆地区岩石圈磁场, 发现3个模型各有其特点: 基于卫星数据建立的MF6模型分辨率有限, 其磁异常条带呈蠕虫状; EMM2010模型岩石圈磁场概貌与MF6模型相似但细节特征十分突出; CGRF2010模型可信度较高, 其分辨率东西部差异较大, 异常形态以团状为主. 通过分析3个模型得到的中国大陆地区岩石圈磁场垂直分量ΔZ的强度及其分布特征发现: ΔZ分量在准噶尔盆地、 塔里木盆地、 柴达木盆地及四川盆地等地区均为正值, 而在天山、 大巴山等地区为负值; ΔZ分量分布在华北岩石圈地块与华南岩石圈地块吻合程度较高; 在青藏高原南部、 西域岩石圈地块北部以及松辽岩石圈地块, 全球模型与CGRF2010模型存在显著差别.

     

    Abstract: The 2010.0 Epoch China Geomagnetic Map and its related models based on ground observation could describe the lithospheric magnetic field of Chinese mainland (refer to as Chinese geomagnetic reference field on 2010 epoch, CGRF2010 for short). We can also use global geomagnetic models, MF6 and EMM2010 for example, to calculate the lithospheric magnetic field of Chinese mainland. Based on the three models, the lithospheric magnetic fields of Chinese mainland were calculated in this paper. Each of them has its own characteristics. MF6 model, which was based on satellite data, has limited resolution and wormlike magnetic anomaly stripes. The model EMM2010 has a very similar overview general picture with the model MF6 but has a lot more details. The model CGRF2010, which has many clustery anomalous areas, is highly reliable, although the resolution of the model is quite different from east to west. The analyses on the vertical component ΔZ of lithospheric magnetic field and its distribution characteristics indicate that the three model-based ΔZ are consistently positive at Junggar, Tarim, Qaidam and Sichuan basin and negative at Tianshan and Dabashan. The ΔZ component distribution of the three models at North China lithospheric block agrees well with that at South China lithospheric block. However, ΔZ component based on global geomagnetic models is notably different from that based on the model CGRF2010 at southern Qinghai-Xizang (Tibet) Plateau, northern Xiyu lithospheric block and whole Songliao lithospheric block.

     

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