A Geophysical Survey of the Interaction between the Chile Ridge and Chile Trench

这是一个主要的地球物理实地项目，旨在调查智利南部边缘，在那里，大洋中脊（智利脊）正沿着智利海沟（智利三联点）俯冲。将收集多道地震反射数据、SEABEAM测深数据、重力数据和疏浚样本。这次调查的主要科学目标是：1）测试洋脊顶部俯冲的构造效应模型; 2）研究在洋脊-海沟碰撞的极端条件下的俯冲过程。这个地区是一个独特的构造环境，也许是世界上研究这种相互作用的最佳地点。在这里，跨越三重连接点的短距离内，可以研究活动扩张中心俯冲之前、期间和之后发生的事情。具体目标包括比较与脊-沟碰撞之前、期间和之后的条件相对应的区域内沟壁的深部结构、表层形态和构造结构。为了实现这些目标，将从跨越沟渠的四个不同断面或走廊收集、处理和分析数据。这些数据将为规划和制定该地区未来ODP钻井的具体钻井目标和钻井地点提供必要的信息。它们还将用于解释和推断区域构造背景下的钻井结果。

This is a major geophysical field program to survey the southern Chile margin where a mid-ocean spreading ridge (Chile Ridge) is being subducted along the Chile Trench (Chile Triple Junction). Collected will be multichannel seismic reflection data, SEABEAM bathymetric data, gravity data and dredge samples. The principal scientific objectives of this survey are 1) to test models for the tectonic effects of ridge crest subduction, and 2) study subduction processes under the extremal conditions of a ridge-trench collision. This area is a unique tectonic setting and perhaps the best place in the world to study this interaction. Here, over a short distance straddling the triple junction, it is possible to study what happens before, during, and after the subduction of an active spreading center. Specific objectives involve comparing the deep structure, surficial morphology, and tectonic fabric of the inner-trench wall in zones corresponding to conditions before, during and after ridge-trench collision. To address these objectives data will be collected, processed and analyzed from four different transects or corridors across the trench. These data will provide the necessary information for planning and developing specific drilling objectives and drill sites for future ODP drilling in the area. They also will be used for interpreting and extrapolating drilling results in a regional tectonic context.