Upper crustal structure of Deception Island area (Bransfield Strait, Antarctica) from gravity and magnetic modelling
Upper crustal structure of Deception Island area (Bransfield Strait, Antarctica) from gravity and magnetic modelling
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DOI：
10.1017/s0954102005002622
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发表时间：
2005-06
影响因子：
1.6
通讯作者：
A. Muñoz-Martín;M. Catalán;J. Martín-Dávila;A. Carbó
中科院分区：
文献类型：
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作者：
A. Muñoz-Martín;M. Catalán;J. Martín-Dávila;A. Carbó
欺骗岛是一座年轻的活火山，位于南极洲半岛和南设得兰群岛之间的布兰斯菲尔德海峡西南部。分析了来自海洋地球物理巡航(DECVOL-99)的新的重磁数据。对欺骗岛周围的48条测线进行了处理和绘制，以获得布格和磁异常图。这些地图显示了明确的重磁异常组以及它们的梯度。为了约束上地壳结构，我们对与该地区主要异常垂直的三条剖面进行了2+1/2D正演模拟，并考虑了以前公布的地震信息。从重力和磁力模型中识别出两种类型的地壳。这些地壳被解释为陆壳(位于欺骗岛以北)和更基本的地壳(欺骗岛以南)。这些地壳类型之间的转换在布格异常图上是明显的，是一个走向NE-SW的高梯度区。磁和重力数据都显示在欺骗岛东部有一个很宽的极小值，这表明它是一个非常低的体积磁化率和低密度侵入体。根据历史上记录的喷发以及热场和浮游场，我们将这一异常解释为部分熔融的侵入体。利用欧拉反褶积技术估计其顶部深度为1.7公里。
Deception Island is a young, active volcano located in the south-western part of Bransfield Strait, between the Antarctic Peninsula and the South Shetland archipelago. New gravity and magnetic data, from a marine geophysical cruise (DECVOL-99), were analysed. Forty-eight survey lines were processed and mapped around Deception Island to obtain Bouguer and magnetic anomaly maps. These maps show well- defined groups of gravity and magnetic anomalies, as well as their gradients. To constrain the upper crustal structure, we have performed 2+1/2D forward modelling on three profiles perpendicular to the main anomalies of the area, and taking into account previously published seismic information. From the gravity and magnetic models, two types of crust were identified. These were interpreted as continental crust (located north of Deception Island) and more basic crust (south of Deception Island). The transition between these crustal types is evident in the Bouguer anomaly map as a high gradient area trending NE-SW. Both magnetic and gravity data show a wide minimum at the eastern part of Deception Island, which suggests a very low bulk susceptibility and low density intrusive body. With historical recorded eruptions and thermal and fumarolic fields, we interpret this anomaly as a partially melted intrusive body. Its top has been estimated to be at 1.7 km depth using Euler deconvolution techniques.