• ISSN 2097-1893
  • CN 10-1855/P
王婕,杨艳艳,纪飞,罗钰馨,泽仁志玛,黄建平,申旭辉. 2024. 岩石圈长波长磁异常及其地质意义. 地球与行星物理论评(中英文),55(0):1-13. doi: 10.19975/j.dqyxx.2023-056
引用本文: 王婕,杨艳艳,纪飞,罗钰馨,泽仁志玛,黄建平,申旭辉. 2024. 岩石圈长波长磁异常及其地质意义. 地球与行星物理论评(中英文),55(0):1-13. doi: 10.19975/j.dqyxx.2023-056
Wang J, Yang Y Y, Ji F, Luo Y X, Ze R Z M, Huang J P, Shen X H. 2024. Lithospheric long-wavelength magnetic anomalies and their geological origins: a review. Reviews of Geophysics and Planetary Physics, 55(0): 1-13 (in Chinese). doi: 10.19975/j.dqyxx.2023-056
Citation: Wang J, Yang Y Y, Ji F, Luo Y X, Ze R Z M, Huang J P, Shen X H. 2024. Lithospheric long-wavelength magnetic anomalies and their geological origins: a review. Reviews of Geophysics and Planetary Physics, 55(0): 1-13 (in Chinese). doi: 10.19975/j.dqyxx.2023-056

岩石圈长波长磁异常及其地质意义

Lithospheric long-wavelength magnetic anomalies and their geological origins: a review

  • 摘要: 在低轨卫星几百千米的高度上,大部分近地表观测到的岩石圈磁异常细节衰减殆尽,只留下衰减较慢的长波长磁异常. 长波长磁异常可以揭示出岩石圈居里面以上显著的物性差异,对于研究地壳深部的物质组成、结构和演化具有重要意义. 为了使读者能从全球尺度上对长波长磁异常的起源形成具体的认识,本文首先回顾了不同时期的卫星磁异常图及主要的岩石圈磁场模型,然后基于CHAOS-7模型计算结果,对500 km高度除极区外幅值大于4 nT的长波长磁异常进行了识别编号,共计29个磁异常. 其中,陆地上磁异常20个,海洋中磁异常9个. 通过对已有研究成果的综述及地质资料的对比分析,逐一介绍了磁异常的起源. 陆地区域的长波长磁异常大多位于前寒武基底,相关的地质单元有太古代地核、元古代地体、富铁建造等,少数位于造山带背景. 海洋区域的长波长磁异常全部都位于洋底高原,普遍与白垩纪时期冈瓦纳大陆裂解相关,具有加厚地壳特征. 因此,针对长波长磁异常的持续深入研究对于地壳生长和演化具有重要意义. 随着我国卫星磁测的蓬勃发展,相信会有越来越多的国内科研人员关注并研究这类大规模磁异常.

     

    Abstract: At the altitude of low-Earth-orbiting satellites, most details of lithospheric magnetic anomalies observed near surface are attenuated, and only slowly decaying long-wavelength magnetic anomalies can be detected. Long-wavelength magnetic anomalies are generated by large-scale magnetized rocks in the Earth’s crust and uppermost mantle at depths shallower than the Curie depth. Interpretation of such lithospheric magnetic anomalies has been used in geological mapping, crustal composition and structure studies, plate tectonic reconstruction, and geodynamics. To introduce the origin of long-wavelength magnetic anomalies at a global scale, we first reviewed satellite magnetic anomaly maps in early periods and calculated anomaly maps using four main lithospheric magnetic field models, including the CHAOS-7, CM6, MF7, and CSES models. Then, based on the result of the CHAOS-7 model at 500 km altitude, 29 long-wavelength magnetic anomalies with amplitudes greater than 4 nT were identified and their geological origins were reviewed. Among these, there were twenty magnetic anomalies over continents and nine over the ocean. The long-wavelength magnetic anomalies over continental areas were mostly located in Precambrian basements related to the Archean nuclei, Proterozoic terrane, and iron-rich formations, with a few located in the orogenic background. The long-wavelength magnetic anomalies in the ocean region were all located in oceanic plateau, generally related to the breakup of Gondwana during the Cretaceous Period, and have the characteristics of thickened crust. Hence, the long-wavelength magnetic anomalies reveal a significant magnetization difference in the deep crust during crustal growth, a key issue that requires further study. Compared to satellite magnetic surveys in some other nations, detecting lithospheric magnetic anomalies by satellite started relatively late in China. The China Seismo-Electromagnetic Satellite (CSES) was launched in February 2018. It was China’s first satellite designed to monitor earthquakes with multiple geophysical payloads, including magnetometers capable of measuring weak signals from the lithosphere. The Macau Science Satellite-1 (MSS-1) was launched in 2023 and is specially used for monitoring the geomagnetic field in low latitudes. Furthermore, a subsequent CSES-02 satellite is planned to be launched in 2024. With the vigorous development of satellite magnetic surveys in China, it is expected that progressively more Chinese researchers will pay attention to long-wavelength magnetic anomalies and promote the study of their origin.

     

/

返回文章
返回