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《Chinese Science Bulletin》 2012年24期
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Magnetic recording of the Cenozoic oceanic crustal accretion and evolution of the South China Sea basin

【摘要】:We review and discuss some of the recent scientific findings made on magnetic data in the South China Sea (SCS). Magnetic anomalies bear extremely rich information on Mesozoic and Cenozoic tectonic evolution. 3D analytical signal amplitudes computed from magnetic anomalies reveal very precisely relict distributions of Mesozoic sedimentary sequences on the two conjugate continental margins, and they are also found very effective in depicting later-stage magmatism and tectonic transitions and zonation within the SCS oceanic crust. Through integrated analyses of magnetic, gravity and reflection seismic data, we define the continent-ocean boundary (COB) around the South China Sea continental margin, and find that the COB coincides very well with a transition zone from mostly positive to negative free-air gravity anomalies. This accurate outlining of the COB is critical for better tracing magnetic anomalies induced by the oceanic crust. The geometrically complex COB and inner magnetic zonation require the introduction of an episodic opening model, as well as a transform fault (here coined as Zhongnan Fault) between the East and Southwest Sub-basins, while within the East and Southwest Sub-basins, magnetic anomalies are rather continuous later-ally, indicating nonexistence of large transform faults within these sub-basins. We enhance magnetic anomalies caused by the shallow basaltic layer via a band-pass filter, and recognize that the likely oldest magnetic anomaly near the northern continental margin is C12 according to the magnetic time scale CK95. Near the southern continental margin, magnetic anomalies are less recognizable and the anomaly C12 appears to be missing. These differences show an asymmetrical opening style with respect to the relict spreading center, and the northern part appears to have slightly faster spreading rates than to the south. The magnetic anomalies C8 (M1 and M2, ~26 Ma) represent important magnetic boundaries within the oceanic basin, and are possibly related to changes in spreading rates and magmatic intensities. The magnetic evidence for a previously proposed ridge jump after the anomaly C7 is not clear. The age of the Southwest Sub-basin has yet to be further examined, most favorably with deep-tow magnetic surveys and ocean drilling. Our magnetic spectral study shows that the shallowest Curie points are located around the eastern part of the Southwestern Sub-basin, whereas within the East Sub-basin Curie depths are smaller to the north of the relict spreading center than to the south. This pattern of Curie depths is consistent to regional heat flow measurements and later-stage volcanic seamount distributions, and we therefore reason that Curie-depth variations are closely associated with later-stage magmatism, rather than with crustal ages. Although magnetic anomalies located around the northern continent-ocean transition zone (COT) are relatively quiet, this area is not a typical magnetic quiet zone since conceptually it differs markedly from an oceanic magnetic quiet zone. The relatively quiet magnetic anomalies are seemingly associated with a shallowing in Curie isotherm and thinning in magnetic layer, but our comprehensive observations suggest that the well-preserved thick Mesozoic sedimentary rocks are major causes for the magnetically quiet zone. The high similarities between various low-pass filtered marine and air-borne magnetic anomalies and satellite magnetic anomalies clearly confirm that deeper magnetic sources (in the lower crust and the uppermost mantle) have contributions to long-wavelength surface magnetic anomalies in the area, as already inferred from magnetically inversed Curie depths. The offshore south China magnetic anomaly (SCMA) becomes more prominent on low-pass filtered marine and air-borne magnetic anomalies and satellite magnetic anomalies, indicating very deeply-buried magnetic sources beneath it.

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【引证文献】
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【参考文献】
中国期刊全文数据库 前1条
1 赵俊峰;施小斌;丘学林;刘海龄;;南海东北部居里面特征及其石油地质意义[J];热带海洋学报;2010年01期
【共引文献】
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1 孙珍;孙龙涛;周蒂;蔡东升;李绪深;钟志洪;姜建群;樊浩;;南海岩石圈破裂方式与扩张过程的三维物理模拟[J];地球科学(中国地质大学学报);2009年03期
2 赵明辉;丘学林;徐辉龙;夏少红;吴振利;李家彪;;南海南部深地震探测及南北共轭陆缘对比[J];地球科学(中国地质大学学报);2011年05期
3 敖威;赵明辉;丘学林;阮爱国;李家彪;;南海西北次海盆及其邻区地壳结构和构造意义[J];地球科学(中国地质大学学报);2012年04期
4 丁巍伟;李家彪;;南海南部陆缘构造变形特征及伸展作用:来自两条973多道地震测线的证据[J];地球物理学报;2011年12期
5 黄忠贤;胥颐;;南海及邻近地区面波层析成像和S波速度结构[J];地球物理学报;2011年12期
6 赵长煜;宋海斌;李家彪;宋洋;田丽花;;南海西南次海盆NH973-1测线地震解释[J];地球物理学报;2011年12期
7 吴招才;高金耀;李家彪;张涛;沈中延;杨春国;;南海北部磁异常特征及对前新生代构造的指示[J];地球物理学报;2011年12期
8 高翔;张健;孙玉军;吴时国;;马尼拉海沟俯冲带热结构的模拟研究[J];地球物理学报;2012年01期
9 高金耀;吴招才;王健;杨春国;张涛;;南海北部陆缘磁静区及与全球大洋磁静区对比的研究评述[J];地球科学进展;2009年06期
10 李春峰;汪品先;Dieter Franke;李家彪;Randell Stephenson;许树坤;Peter Michael;周祖翼;翦知湣;李前裕;刘志飞;耿建华;木村学;阎贫;丘学林;王嘹亮;解习农;吴时国;吴能友;;南海张裂过程及其对晚中生代以来东南亚构造的启示——IODP建议书735-Full介绍[J];地球科学进展;2009年12期
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1 吴振利;南海西北次海盆张裂特征及扩张方式[D];中国科学院研究生院(海洋研究所);2010年
2 赵长煜;南海大陆边缘盆地构造热演化模拟[D];中国地质大学(北京);2012年
3 雷超;南海北部莺歌海—琼东南盆地新生代构造变形格局及其演化过程分析[D];中国地质大学;2012年
4 刘鸿;南海磁静区成因探讨及地质意义[D];中国科学院研究生院(海洋研究所);2013年
中国硕士学位论文全文数据库 前1条
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【同被引文献】
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2 李家彪;;南海大陆边缘动力学:科学实验与研究进展[J];地球物理学报;2011年12期
3 李家彪;丁巍伟;高金耀;吴自银;张洁;;南海新生代海底扩张的构造演化模式:来自高分辨率地球物理数据的新认识[J];地球物理学报;2011年12期
4 黄忠贤;胥颐;;南海及邻近地区面波层析成像和S波速度结构[J];地球物理学报;2011年12期
5 解习农;张成;任建业;姚伯初;万玲;陈慧;康波;;南海南北大陆边缘盆地构造演化差异性对油气成藏条件控制[J];地球物理学报;2011年12期
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7 何廉声;南海的形成、演化与油气资源(英文)[J];海洋地质与第四纪地质;1988年02期
8 姚伯初;南海海盆新生代的构造演化史[J];海洋地质与第四纪地质;1996年02期
9 吕文正,柯长志,吴声迪,刘建华,林长松;南海中央海盆条带磁异常特征及构造演化[J];海洋学报(中文版);1987年01期
【二级参考文献】
中国期刊全文数据库 前3条
1 施小斌,丘学林,夏戡原,周蒂;南海热流特征及其构造意义[J];热带海洋学报;2003年02期
2 何家雄;夏斌;王志欣;刘宝明;孙东山;;南海北部边缘盆地西区油气运聚成藏规律与勘探领域剖析[J];石油学报;2006年04期
3 何家雄,李明兴,陈伟煌;莺歌海盆地热流体上侵活动与天然气运聚富集关系探讨[J];天然气地球科学;2000年06期
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