摘要
根据高阶地磁场模型NGDC-720-V3,研究青藏高原东南缘地壳磁异常的空间分布和高度衰减特征,探讨不同波长成分对总体磁异常的贡献,分析地壳磁异常与地质构造、地球物理场的联系。结果显示:(1)构造稳定的四川盆地分布着强正磁异常;(2)龙门山地区分布着较强的负磁异常;(3)川西北、滇西造山带为负磁异常或弱磁异常;(4)滇中地块磁异常为团状和带状分布,正负异常交错出现,磁异常衰减快,异常源较浅;(5)沿金沙江—红河断裂带分布有清晰的正负磁异常成条带,并一直向东南延伸至越南北部;(6)龙门山断裂带、丽江—小金河断裂带、红河断裂带是地壳磁场强弱或正负异常的过渡带;(7)滇中地块东部磁异常以康定—奕良—水城断裂和弥勒—师宗—水城断裂带为界。研究结果对认识青藏高原东南缘地壳构造及演化、区域地球动力学过程和地下资源勘探有重要意义。
Based on the high-order geomagnetic field model NGDC-720-V3,the spatial distribution and height attenuation characteristics of crustal magnetic anomalies in the southeastern margin of the Tibetan Plateau are studied,the contribution of different wavelength components to the overall magnetic anomalies is discussed,and the relationship between crustal magnetic anomalies and geological structures and geophysical fields is analyzed.The results show that:(1)strong positive magnetic anomalies is distributed in the tectonically stable sichuan basin.(2)There are strong negative magnetic anomalies in the Longmen Mountains.(3)The orogenic belts in northwest Sichuan and West Yunnan are negative magnetic anomalies or weak magnetic anomalies.(4)The magnetic anomalies in the central Yunnan block are clustered and banded,with alternating occurrence of positive and negative anomalies.The magnetic anomalies decay quickly and the source of the anomalies is shallow.(5)There are clear bands of positive and negative magnetic anomalies along the Jinsha Jiang-Honghe fault zone,and they extend southeast to northern Vietnam.(6)Longmenshan faults zone,Lijiang-Xiaojinhe fault zone and Honghe fault zone are transitional zones of crustal magnetic field strength or positive and negative anomalies.(7)The eastern magnetic anomaly of the central Yunnan block is bounded by the Kangding-Yiliang-Shuicheng fault zone and the Maitreh-Shizong-Shuicheng fault zone.The results are of great significance for understanding the crustal structure and evolution,regional geodynamic processes and underground resource exploration in the southeastern margin of the Qinghai-Tibet Plateau.
作者
瞿梦茹
梁坤
胡毅力
QU Mengru;LIANG Kun;HU Yili(Yunnan Yuzhen Earthquake Engineering Co.,Ltd,Kunming 650224,China;Departement of Geophysics,Yunnan University,Kunming 650504,China)
出处
《高原地震》
2022年第3期6-15,共10页
Plateau Earthquake Research
关键词
地磁场模型
地壳磁异常
空间分布
青藏高原东南缘
Geomagnetic field model
Crustal magnetic anomaly
Spatial distribution
The southeastern of Qinghai-Tibet plateau
作者简介
瞿梦茹(1988—),女,湖南醴陵人,工程师,主要从事地震安全性评价工作。E-mail:124694724@qq.com;通讯作者:胡毅力(1955—),男,云南澄江人,云南大学地球物理系教授,从事地球内部物理、地磁学研究。E-mail:ylhu929@163.com。
