Magnetized magma intrusions being sources of a weak and a strong lunar magnetic anomaly revealed by 3D distribution of magnetizationOAEI
Magnetized magma intrusions being sources of a weak and a strong lunar magnetic anomaly revealed by 3D distribution of magnetization
In this work,we aim to investigate the origin of the magnetic carriers in the lunar crust and the intensity of the ancient dynamo field.The magnetization and depth range of magnetic carriers are studied under a weak and a strong magnetic anomaly in Mare Tranquillitatis and in Oceanus Procellarum,respectively,where the surface ages are 3.6 and 3.3 billion years.A sophisticated three-dimensional amplitude inversion software program from a geophysical survey is used to reconstruct the distributions of magnetization in the lunar crust.Because no globally measured surface magnetic field exists for the Moon,a crustal magnetic anomaly model with a grid resolution of 0.2° is used.The depth range of the magnetic source is fixed by the boundary identified by a relative criterion,which is 20％of the recovered maximum magnetization.The central burial depths of the magnetic carriers are approximately 15 km and 25 km under Reiner Gamma and Mare Tranquillitatis,respectively.The volumes of the two magnetic sources are at scales of 104 and 105 km3,respectively.The aforementioned differences may imply a hotter crust under Reiner Gamma than Mare Tranquillitatis by 3.3 billion years.The results support the view that the magma intrusions magnetized by an ancient magnetic field could be the origin of magnetic anomalies under Reiner Gamma and Mare Tranquillitatis.Compared with previous works,the maximum magnetization of 3 A/m under Reiner Gamma supports the intensity of the field being several microteslas.
HongYi Wang;Shuo Yao;ZeLin Li;LiangHui Guo;Jing Yang;ChangLi Yao;Yuan Fang;ZhaoJin Rong
School of Geophysics and Information Technology,Research Center of Lunar and Planetary Remote Sensing Exploration,China University of Geosciences(Beijing),Beijing 100083,China||Key Laboratory of Intraplate Volcanoes and Earthquakes(China University of Geosciences,Beijing),Ministry of Education,Beijing 100083,ChinaHebei University of Engineering,Handan Hebei 056038,ChinaSchool of Geophysics and Information Technology,Research Center of Lunar and Planetary Remote Sensing Exploration,China University of Geosciences(Beijing),Beijing 100083,ChinaKey Laboratory of Earth and Planetary Physics,Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing 100029,China
lunar magnetic anomaly3D distribution of magnetizationReiner GammaMare Tranquillitatis
《地球与行星物理（英文）》 2024 (005)
711-727 / 17
This work was supported by the National Key R&D Program of China(Grant No.2021YFA0715101).S.Yao was supported by the Chinese 111 Project(Contract No.B20011)and by the Fundamental Research Funds for the Central Universities.H.Y.Wang was supported by the Innovation Experimental Class Program.The 3D magnetic inversion algorithm and the code were originally devel-oped under the consortium research project Joint/Cooperative Inversion of Geophysical and Geological Data,University of British Columbia-Geophysical Inversion Facility(UBC-GIF),Department of Earth and Ocean Sciences,Vancouver,British Columbia.S.Yao thanks Z.Ma and T.Yang for their helpful discussions.
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