| Serpentinized Peridotite as Source of Aeromagnetic Anomalies |
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| 作者姓名： | LiuQingsheng LiuQingsong ZhangZeming YangTao FuYuanyuan |
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| 作者单位： | [1]InstituteofGeophysicsandGeomatics,ChinaUniversityofGeosciences,Wuhan430074,China [2]InstituteforRockMagnetism,UniversityofMinnesota,MN,55455,USA [3]InstituteofGeology,ChineseAcademyofGeologicalSciences,Beijing100037,China |
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| 基金项目： | 国家重点基础研究发展计划(973计划)，中国地质大学科研和教改项目 |
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| 摘 要： | The source of long-wavelength aeromagnetic anomalies appears to originate from the eartlrs deep crust. Constrained by previous studies on geochemical, petrologic analysis, the eclogite and serpentinized peridotite samples from drill hole ZK703 at Donghai in the western Sulu ultrahigh-pressure (UHP) terrane, East China, were unambiguously exhumed from the lower crust and the upper mantle, providing significant information about the magnetic properties of rocks at a deeper part of the crust. Results show that the serpentinization process favors the neoformation of nearly stoichiometric magnetite, resulting in the enhancement of its magnetization up to 8.6 A/m, which is sufficient enough to contribute to some magnetic anomalies. In contrast, eclogite samples have only weaker magnetization (generally less than 0.05 A/m) compared to serpentinized peridotite. Nevertheless, experiments under the lower crustal conditions are necessary to further support these conclusions.
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| 关 键 词： | 蛇纹橄榄岩 航空磁测异常 自然磁化 波长长度 |
Serpentinized Peridotite as Source of Aeromagnetic Anomalies |
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| LiuQingsheng LiuQingsong ZhangZeming YangTao FuYuanyuan.Serpentinized Peridotite as Source of Aeromagnetic Anomalies[J].Journal of China University of Geosciences,2004,15(4):416-419. |
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| Authors: | Liu Qingsheng Liu Qingsong Zhang Zeming Yang Tao Fu Yuanyuan |
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| Abstract: | The source of long-wavelength aeromagnetic anomalies appears to originate from the earth's deep crust. Constrained by previous studies on geochemical, petrologic analysis, the eclogite and serpentinized peridotite samples from drill hole ZK703 at Donghai in the western Sulu ultrahigh-pressure (UHP) terrane, East China, were unambiguously exhumed from the lower crust and the upper mantle, providing significant information about the magnetic properties of rocks at a deeper part of the crust. Results show that the serpentinization process favors the neoformation of nearly stoichiometric magnetite, resulting in the enhancement of its magnetization up to 8.6 A/m, which is sufficient enough to contribute to some magnetic anomalies. In contrast, eclogite samples have only weaker magnetization (generally less than 0.05 A/m) compared to serpentinized peridotite. Nevertheless, experiments under the lower crustal conditions are necessary to further support these conclusions. |
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| Keywords: | Sulu UHP terrane eclogite serpentinized peridotite long-wavelength aeromagnetic anomaly natural remanent magnetization |
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