Current tectonics of the Tonga–New Hebrides region
Current tectonics of the Tonga–New Hebrides region
复制标题
DOI：
10.1016/s0012-821x(98)00212-x
复制
发表时间：
1998-12
影响因子：
5.3
通讯作者：
B. Pelletier;S. Calmant;R. Pillet
中科院分区：
文献类型：
--
作者：
B. Pelletier;S. Calmant;R. Pillet
本文提出了汤加-新赫布里底群岛地区的现代构造图，它结合了测深、卫星重力、地震活动、磁场测量和GPS观测的数据。过去十年在劳和北斐济弧后盆地收集的震源机制和大量测深数据表明，变形分布在许多扩展脊上，而不是像以前认为的那样，以扩散和剪切为主。该地区沿弧的消耗速率和沿弧后盆地扩张中心的张开速率变化较大。劳弧后盆地和北斐济弧后盆地的几何形状和扩张速度，以及汤加弧和新赫布里底弧的分割，与路易斯维尔、D'Entrecasteaux和Loyalty等地震脊的俯冲密切相关，并受到其显著影响。在俯冲的地震脊进入海沟的地方，我们观察到较慢的收敛，弧横向走滑断裂，在弧的后部逆冲，以及缓慢或不存在的弧后扩张。快速俯冲与弧后快速张开有关。有时需要在弧后域平行扩展脊来适应快速的收敛运动。
This paper proposes a present-day tectonic map of the Tonga–New Hebrides region, the result of combining data from bathymetry, satellite-derived gravity, seismicity, magnetic measurements and GPS observations. Focal mechanisms and a large amount of bathymetric data collected during the last decade in the Lau and North Fiji back-arc basins indicate a deformation distributed over numerous spreading ridges rather than diffuse and shear-dominated as was previously thought. The region is also characterised by a large variation of both consumption rate along the arcs and opening rate along the back-arc basins spreading centres. Geometry and rate of spreading in the Lau and North Fiji back-arc basins, and segmentation of the Tonga and New Hebrides arcs, are closely related to, and significantly influenced by, the subduction of aseismic ridges, namely the Louisville, D'Entrecasteaux and Loyalty ridges. Where subducting aseismic ridges enter the trenches, we observe slower convergence, arc-transverse strike-slip faulting, thrusting at the rear of arcs, and slow or absent back-arc spreading. Rapid subduction correlates with fast back-arc opening. Sometimes parallel spreading ridges in the back-arc domain are required to accommodate the fast motion of convergence.