Variation in Upper Plate Crustal and Lithospheric Mantle Structure in the Greater and Lesser Antilles from Ambient Noise Tomography
Variation in Upper Plate Crustal and Lithospheric Mantle Structure in the Greater and Lesser Antilles from Ambient Noise Tomography
复制标题
环境噪声层析成像显示大、小安的列斯群岛上板块地壳和岩石圈地幔结构的变化
DOI：
10.1002/essoar.10506559.1
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发表时间：
2021
期刊：
影响因子：
--
通讯作者：
Schlaphorst D
中科院分区：
文献类型：
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作者：
Schlaphorst D
大安的列斯群岛弧和小安的列斯群岛弧的地壳和上地幔结构提供了对古老缓慢扩张的海洋岩石圈缓慢收敛的独特区域中关键俯冲带过程的见解。我们使用从岛屿宽带地震台站收集的环境噪声层析成像和作为小安的列斯群岛实验中挥发物回收的一部分安装的临时海底地震计网络来绘制大安的列斯群岛东部和小安的列斯群岛弧的地壳和上地幔剪切波速度。以2.0 km/s等值线的深度为代表，我们发现格林纳达和托巴哥盆地南部的沉积厚度可达15 km，弧附近和北部的沉积厚度较薄。我们观察到较厚的地壳，根据深度的4.0公里/秒的速度等值线，下面的弧平台，最大的地壳厚度约30公里，可能与地壳增加从弧火山作用通过时间。在莫纳通道、瓜德罗普-马提尼克和格林纳丁斯下方的地幔楔（30-50 km深度）中存在明显的低速带（4.2-4.4 km/s）。莫纳通道地幔异常可能与正在进行的扩张有关，而瓜德罗普-马提尼克岛和格林纳达异常可能与流体通量，上涌，和/或部分熔融有关附近的板特征。瓜德罗普-马提尼克异常的位置略偏南的倾斜俯冲断裂带。这一特征可以用三维地幔流、板块中的间隙、可变的板块水合作用和/或熔体动力学（包括积水和与上板块的相互作用）来解释。
The crust and upper mantle structure of the Greater and Lesser Antilles Arc provides insights into key subduction zone processes in a unique region of slow convergence of old slow‐spreading oceanic lithosphere. We use ambient noise tomography gathered from island broadband seismic stations and the temporary ocean bottom seismometer network installed as part of the Volatile Recycling in the Lesser Antilles experiment to map crustal and upper mantle shear‐wave velocity of the eastern Greater Antilles and the Lesser Antilles Arc. Taking the depth to the 2.0 km/s contour as a proxy, we find sediment thickness up to 15 km in the south in the Grenada and Tobago basins and thinner sediments near the arc and to the north. We observe thicker crust, based on the depth to the 4.0 km/s velocity contour, beneath the arc platforms with the greatest crustal thickness of around 30 km, likely related to crustal addition from arc volcanism through time. There are distinct low velocity zones (4.2–4.4 km/s) in the mantle wedge (30–50 km depth), beneath the Mona Passage, Guadeloupe‐Martinique, and the Grenadines. The Mona passage mantle anomaly may be related to ongoing extension there, while the Guadeloupe‐Martinique and Grenadine anomalies are likely related to fluid flux, upwelling, and/or partial melt related to nearby slab features. The location of the Guadeloupe‐Martinique anomaly is slightly to the south of the obliquely subducted fracture zones. This feature could be explained by either three‐dimensional mantle flow, a gap in the slab, variable slab hydration, and/or melt dynamics including ponding and interactions with the upper plate.