New insights on intraplate volcanism in French Polynesia from wavelet analysis of GRACE, CHAMP, and sea surface data
New insights on intraplate volcanism in French Polynesia from wavelet analysis of GRACE, CHAMP, and sea surface data
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DOI：
10.1029/2005jb004141
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发表时间：
2006-09
影响因子：
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通讯作者：
I. Panet;A. Chambodut;M. Diament;M. Holschneider;O. Jamet
中科院分区：
文献类型：
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作者：
I. Panet;A. Chambodut;M. Diament;M. Holschneider;O. Jamet
本文利用球面几何小波对现代重磁卫星资料进行了表征和分析，讨论了超井火山活动的成因。利用GRACE卫星GGM 02 S全球重力场和KMS 02测高网格计算了中南部太平洋的精细重力场，利用CHAMP数据计算了地磁异常场。磁异常的特点是海底扩张的磁线理和土阿莫图地区的强烈异常，我们将其解释为地壳增厚的证据。我们通过连续的小波分析来解释我们的重力场，从而可以初步了解内部密度分布。我们还计算连续小波分析的测深的贡献，以区分深源和浅源。根据我们的分析所揭示的不同链的重力签名，各种过程是在法属波利尼西亚火山活动的起源。作为证据，我们在社会群岛上显示了一个大规模的异常，我们将其解释为深锚地幔柱的重力特征。库克-奥斯特拉尔链的重力特征表明其起源复杂，可能涉及深部过程。最后，我们讨论的特定位置的Marquesas链的火山活动的起源可能会干扰二次对流卷或可能是由岩石圈的弱点，由于区域应力场控制，或其他有关的存在附近的土阿莫土高原。
In this paper, we discuss the origin of superswell volcanism on the basis of representation and analysis of recent gravity and magnetic satellite data with wavelets in spherical geometry. We computed a refined gravity field in the south central Pacific based on the GRACE satellite GGM02S global gravity field and the KMS02 altimetric grid, and a magnetic anomaly field based on CHAMP data. The magnetic anomalies are marked by the magnetic lineation of the seafloor spreading and by a strong anomaly in the Tuamotu region, which we interpret as evidence for crustal thickening. We interpret our gravity field through a continuous wavelet analysis that allows to get a first idea of the internal density distribution. We also compute the continuous wavelet analysis of the bathymetric contribution to discriminate between deep and superficial sources. According to the gravity signature of the different chains as revealed by our analysis, various processes are at the origin of the volcanism in French Polynesia. As evidence, we show a large-scale anomaly over the Society Islands that we interpret as the gravity signature of a deeply anchored mantle plume. The gravity signature of the Cook-Austral chain indicates a complex origin which may involve deep processes. Finally, we discuss the particular location of the Marquesas chain as suggesting that the origin of the volcanism may interfere with secondary convection rolls or may be controlled by lithospheric weakness due to the regional stress field, or else related to the presence of the nearby Tuamotu plateau.