| 南沙群岛及其邻区低频和中频重力场的分离 |
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| 引用本文： | 陈雪,苏达权,林进峰.南沙群岛及其邻区低频和中频重力场的分离[J].热带海洋学报,1997(1). |
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| 作者姓名： | 陈雪 苏达权 林进峰 |
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| 作者单位： | 中国科学院南海海洋研究所!广州，510301，中国科学院南海海洋研究所!广州，510301，中国科学院南海海洋研究所!广州，510301 |
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| 基金项目： | 国家自然科学基金!49574226 |
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| 摘 要： | 建立了一个分离中、低频重力场的数学模型。根据南沙群岛地质构造的特征，选择4条具有代表性的重力测线N2，N9，N10和N11的自由空间重力异常，进行福里哀频谱值的计算并研究振幅谱值的分布规律，确定61.44km为4条重力测线的低频和中频重力场的临界值；设计分开低频和中频重力场的分离因子，分离出4条重力剖面的低频和中频重力异常；进而分析其低频和中频重力异常的特征。结果表明：N2和N11频谱值的分布带窄，低频重力场显著，中频重力场不显著；N9和N10的频谱值分布带宽，中频和低频重力场均显著。分析了它们和地质构造的关系。曾母盆地、南华盆地和南薇盆地的低频重力异常和沉积厚度成反关系，其余地区成正关系。
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| 关 键 词： | 南沙群岛 中.低频重力场 地质构造 |
THE SEPARATION OF LOW FREQUENCY AND MIDDLE FREQUENCY GRAVITY FIELDS IN NANSHA ISLANDS AND ITS ENVIRONS |
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| CHEN Xue, SU Daquan, LIN Jinfeng.THE SEPARATION OF LOW FREQUENCY AND MIDDLE FREQUENCY GRAVITY FIELDS IN NANSHA ISLANDS AND ITS ENVIRONS[J].Journal of Tropical Oceanography,1997(1). |
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| Authors: | CHEN Xue SU Daquan LIN Jinfeng |
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| Abstract: | A method of separating low and middle frequency gravity fields is presentedin this paper. Based on the characteristics of geological structures in Nansha Islands,the free air gravities of four profiles N2, N9, N10, N11 were selected from NanshaIslands. Their Fourier frequency spectrums were calculated. The distributionregularities of amplitude spectrums were studied. The critical value between low andmiddle frequency gravity fields was determined as 61.44km for the free air gravity offour profiles. The separation factor was designed. Then low frequency and middle frequency gravity flelds were obtained. The low frequency gravity field is obvious in N2and N11 profiles, but the midddle frequency gravity field is not obvious, anddistributive belts of the frequency spectrum are narrow. In N9 and N10 profiles, thelow and middle frequency gravity fields are obvious and distributive belts of the frequency spectrum are wide. The relationship between separated gravity fields and geological structures were studied. The low frequency gravity fields are inverse proportionalto sedimentary thickness of basins in Zengmu Basin, Nanhua Basin and Nanwei Basin, but directly proportional in other areas. |
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| Keywords: | Nansha Islands low and middle frequency gravity fields geological structures |
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