马尼拉俯冲带中段增生楔精细构造特征及微型圈闭盆地发育模式探讨

对马尼拉俯冲带中段高精度地形数据编辑后绘制成图,联合之前所获取的地震剖面数据,对俯冲带增生楔的精细构造地貌特征及发育模式进行了深入探讨.在增生楔下构造区发现了大量狭长的微型圈闭盆地,经过对其平面断裂特点与深部应力状态的分析,发现增生楔从俯冲前缘到脊顶区其构造特点的转变对应着微型圈闭盆地4个完整的发育阶段,即初期的加积断裂阶段、中期的圈闭成盆阶段、后期的挤压消亡阶段乃至最终的隆升推覆阶段,揭示出一种新型的俯冲带增生楔发育模式,并推断其本质是深部板片俯冲活动所产生的压应力在海底面的表现.

Discussion on the fine tectonic features of accretionary wedge and developing patterns of minisize trapped basins at middle part of Manila Subduction Zone

High-precision large-scale multi-beam topographic data was edited carefully and used to plot submarine geomorphic shadow graph finally. The fine tectonic features of accretionary wedges and developing patterns of the minisize trapped basins at middle part of Manila Subduction Zone were discussed deeply associating with a seismic profile crossing the study area collected before. Multiple long and narrow minisize trapped basins were identified in lower tectonic zone of accretionary wedge. After analyzing the planar break feature and its deep stress status, we proved that the change of tectonic features from lower tectonic zone to top of the wedge was corresponding to a complete developing process of the minisize trapped basin, that is, from accretion and break stage at start to trap and basin formation in middle stage, extrusion and extinction during late stage, and elevation and nappe stage at last. A new type of developing pattern for accretionary wedges was disclosed during the process and the essence of it was manifested to be the expression of compressive stress on sea floor which was produced by subduction activities of deep plate.