Bending-Related Topographic Structures of the Subducting Plate in the Northwestern Pacific Ocean
Bending-Related Topographic Structures of the Subducting Plate in the Northwestern Pacific Ocean
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DOI：
10.1007/978-90-481-8885-7_1
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发表时间：
2011-01-01
期刊：
影响因子：
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通讯作者：
Nakanishi, Masao
中科院分区：
文献类型：
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作者：
Nakanishi, Masao
利用现有的多波束测深数据，研究了日本千岛群岛西部和北方伊豆-小笠原海沟沿着俯冲洋板块弯曲引起的拉长地形结构。磁异常线理也重新确定使用现有的地磁数据，以揭示弯曲相关的地形结构走向的控制因素。新的测深图表明，大多数与弯曲有关的地形结构存在于5 600米以上的向海沟斜坡。该地图显示，弯曲相关的地形结构平行于海沟轴线或继承海底扩张组构。磁异常的详细识别揭示了与传播脊相关的弯曲线理和线理的不连续性。在沟-沟-沟三联点附近发现了一个与白垩纪中期平静期的扩张脊有关的具有细长陡崖的槽。详细的测深图和磁异常线理图之间的比较表明，在深海丘组构与海沟轴线之间的角度小于约30度的地方，深海丘组构被重新激活。根据新断层是否平行于海沟轴线发展或继承的海底扩张组构是否重新激活，将弯曲相关构造的地形表现分为两种类型。
Elongated topographic structures associated with bending of the subducting oceanic plate along the western Kuril, Japan and northern Izu-Ogasawara trenches, were investigated using available multibeam bathymetric data. Magnetic anomaly lineations were also reidentified using available geomagnetic data to reveal controlling factors for strikes of bending-related topographic structures. The new bathymetric map demonstrates that most of bending-related topographic structures exist in the oceanward trench slopes deeper than 5,600 m. The map reveals that bending-related topographic structures are developed parallel to the trench axis or inherited seafloor spreading fabrics. Detailed identification of magnetic anomalies reveals curved lineations and discontinuity of lineations associated with propagation ridges. A trough with elongated escarpments associated with the propagating ridge in mid-Cretaceous Quiet Period was discovered near the trench-trench-trench triple junction. Comparison between the detailed bathymetric and magnetic anomaly lineation maps elucidates that abyssal hill fabrics were reactivated where the angle between abyssal hill fabrics and trench axis is less than about 30 degrees. The topographic expression of bending-related structures are classified into two types according to whether new faults develop parallel to the trench axis or inherited seafloor spreading fabrics reactivate.