首页|北部海岸带(台州以北)航磁推断的基底构造特征

北部海岸带(台州以北)航磁推断的基底构造特征

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北部海岸带(台州以北)横跨华北地块、下扬子地块和华夏地块三个构造单元,区域地质构造复杂,岩浆活动强烈,断裂发育.本文以最新编制的航磁资料为主,结合航空重力、区域地质和实测岩石物性资料等,对北部海岸带(台州以北)进行了航磁综合解释.依据化极航磁ΔT反映的东西分带和南北分块的特点,详细分析了磁场面貌、特征及其与区域构造的对应关系,展现了不同特征的磁场是构造、岩浆活动以及地层分布等信息的综合体现,并进一步对基底岩相构造进行了划分和研究.郯庐断裂带以西的渤海海岸带,以团块状正磁异常为特征,基底由太古宇迁西群、鞍山群、泰山群及古元古界变质岩构成,以东为变化负磁异常区,磁场由鞍山群、胶东群、辽河群及粉子山群变质岩系及部分中酸性岩浆岩引起;南黄海海岸带的团块状正磁异常与太古宇变质岩有关,基底由元古宇变质岩构成;苏南-勿南沙和浙闽沿海地区的剧烈变化磁异常带,是被中新生代岩浆岩强烈改造了的元古宇弱磁性变质基底;东海海岸带是以北北东向展布的正负相间磁异常带为特征,变质基底由元古宇陈蔡群的变质岩构成,正磁异常带主要是岩浆岩带的反映.基底岩相构造在航空重磁场上的特征,对区内构造单元划分及地质演化具有重要的参考价值.
Basement characteristics reflected by aeromagnetic data in the northern coastal zone of Taizhou
On the basis of the latest aeromagnetic data of the northern coastal zone of Taizhou,integrated interpretation is performed in this study by combining airborne gravity data,regional geology,and magnetic susceptibility information.According to different zone and block characteristics of the reduced-to-the-pole(RTP)aeromagnetic data,the magnetic field characteristics and related structural division are determined and described in detail.The variation in aeromagnetic field characteristics reflects tectonic movement,magmatic activity,and stratigraphic distribution,which further delineates the structural characteristics of the basement lithofacies,aeromagnetic anomaly characteristics,and distribution regularity of the magmatic rocks and faults.The Bohai coastal zone,located to the west of the Tancheng-Lujiang fault,is characterized by block-like positive aeromagnetic anomalies.The basement is composed of rocks of the Archean Qianxi,Anshan,and Taishan groups,as well as Paleoproterozoic metamorphic rocks.The area to the east of the Tancheng-Lujiang fault is dominated by variable negative aeromagnetic anomalies.The magnetic field is caused by the metamorphic rocks of the Anshan,Jiaodong,Liaohe,and Fenzishan groups,in addition to several intermediate-acid magmatic rocks.The block-like positive aeromagnetic anomaly in the coastal zone of the South Yellow Sea might be related to Archean metamorphic rocks,and the basement rocks are Proterozoic metamorphic.The dramatic changes in the aeromagnetic anomaly belts in the southern Jiangsu-Wunansha region and the Zhejiang-Fujian coast are attributed to the strong reformation of the Proterozoic metamorphic basement rocks of weak magnetism to Mesozoic-Cenozoic magmatic rocks.The coastal zone of the East China Sea is characterized by NNE positive and negative aeromagnetic anomalies,whereas the metamorphic basement is composed of metamorphic rocks of the Proterozoic Chencai Group.The positive aeromagnetic anomaly belt is a reflection of the magmatic rock belt.In summary,this study reveals the characteristics of basement lithofacies in airborne gravity and aeromagnetic fields,which provides an important reference for geological evolution and the division of tectonic units.

Aeromagnetic dataBouguer anomaly of airborne gravitymagnetic field characteristicsbasement lithofaciesnorthern Taizhoucoastal zone

王明、李皎皎、张永军、李逸川、徐璐平

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中国自然资源航空物探遥感中心,北京 100083

自然资源部航空地球物理与遥感地质重点实验室,北京 100083

航磁 航重 磁场特征 基底岩相 北部海岸带

Foundation for Youth Innovative Research of Key Laboratory of Airborne Geophysics and Remote Sensing Geology of MNRNational Key Research and Development Program of ChinaInvestigation and application of airborne geophysical remote sensing in Bohai Coastal Zone

2020YFL082017YFC0602204DD20160150

2024

10.1007/s11770-021-0887-1

应用地球物理(英文版)
中国地球物理学会

应用地球物理(英文版)

影响因子：1.01
ISSN：1672-7975
年,卷(期)：2024.21(1)
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