Crustal Structure of the Japan Trench: The Effect of Subduction of Ocean Crust
Crustal Structure of the Japan Trench: The Effect of Subduction of Ocean Crust
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DOI：
10.2973/dsdp.proc.5657.110.1980
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发表时间：
1980-11
期刊：
影响因子：
5.8
通讯作者：
S. Murauchi;W. Ludwig
中科院分区：
文献类型：
--
作者：
S. Murauchi;W. Ludwig
根据Glomar Challenger 56和57的深海钻探结果，对在日本海沟进行的地震折射测量进行了评估和综合，得出了地壳结构的示意图。太平洋地壳板块以低角度俯冲于日本东北部大陆块体的前缘，并在深部跟随和田地-贝尼奥夫带的上部地震带。逆冲推覆的大陆地壳延伸到海沟轴线30公里以内；从那时起，较低的内海沟斜坡由厚厚的楔形低速沉积体形成。这些沉积物的体积太小，不能代表从太平洋板块刮下来并从陆地上运来的所有沉积物。这表明，大量的沉积物沿着大陆块体和下降板块之间的滑移面向下携带。沉积物的脱水对滑动面起到了润滑作用。滑动面向上迁移到上覆的大陆边缘，导致物质从其底部移走。这种构造侵蚀导致大陆边缘的下沉和向陆地的后退。
Evaluation and synthesis of seismic-refraction measurements made in the Japan trench in the light of the results of deep-sea drilling from Glomar Challenger Legs 56 and 57 result in a schematic section of the crustal structure. The Pacific Ocean crustal plate underthrusts the leading edge of the continental block of Northeast Japan at a low angle and follows at depth the upper seismic belt of the Wadati-Benioff zone. Overthrust continental crust extends to within 30 km of the trench axis; thenceforward the lower inner trench slope is formed by a thick, wedge-shaped body of low-velocity sediments. The volume of these sediments is too small to represent all the sediments scraped off the Pacific plate and transported from land. This indicates that substantial amounts of sediment are carried down along slip planes between the continental block and the descending plate. Dewatering of the sediments lubricates the slip planes. The slip planes migrate upward into the overlying continental edge, causing removal of material from its base. This tectonic erosion causes subsidence and landward retreat of the continental edge.