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| 马尼拉俯冲带北段增生楔形态结构及演化过程 |
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王红丽1, 赵强2,3, 黄金莲4, 范建柯5
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1.盐城师范学院城市与规划学院, 江苏 盐城 224007;2.自然资源部第一海洋研究所, 海洋沉积与环境地质重点实验室, 山东 青岛 266061;3.青岛海洋科学与技术试点国家实验室, 海洋地质过程与环境功能实验室, 山东 青岛 266061;4.中国石油天然气股份有限公司东方地球物理公司研究院大港分院, 天津 300280;5.中国科学院海洋研究所海洋地质与环境重点实验室, 山东 青岛 266071
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| 摘要: |
| 为揭示马尼拉增生楔的形态结构并加深对其演化过程的理解，本文对横穿马尼拉俯冲带北段的几条典型地震剖面进行了深度偏移处理，得到叠前深度偏移剖面和深度-速度模型，并对马尼拉增生楔的形态结构及内部特征进行了精细解释，将马尼拉增生楔分为原始沉积段、褶皱变形段、逆冲推覆段和背逆冲段四个部分，分别代表增生楔演化的不同阶段。推断马尼拉增生楔下部存在由早期仰冲的菲律宾海板块的残留块体构成的弧前基盘，弧前基盘是控制马尼拉增生楔形成演化的关键构造。弧前基盘前端是拆离滑脱面突然降阶并在地震剖面上“隐没”的部位；弧前基盘向增生楔底部的不断挤入导致了逆冲脱序断层的渐次发育以及增生楔向弧前基盘之上的不断爬升，导致了增生楔上、下陆坡地貌的分化，并为褶皱变形段和逆冲推覆段的地层形变提供了主要的应力。 |
| 关键词: 马尼拉海沟 增生楔 弧前基盘 滑脱面 脱序断层 |
| DOI：10.11759/hykx20181124002 |
| 分类号:P736 |
| 基金项目:国家自然科学基金面上基金（41876043） |
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| Morphological structure and evolution of accretionary wedge in the northern part of Manila subduction zone |
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WANG Hong-li1, ZHAO Qiang2,3, HUANG Jin-lian4, FAN Jian-ke5
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1.School of Urban Planning, Yancheng Teachers University, Yancheng 224007, China;2.Key Laboratory of Marine Sedimentology and Environment Geology, First Institute of Oceanography, Ministry of Natural Resource, Qingdao 266061, China;3.Key Laboratory for Marine Geology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266061, China;4.Dagang Branch of GRI, BGP Inc., CNPC, Tianjin 300280, China;5.Key Laboratory of Marine Geology and Environment, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China
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| Abstract: |
| To reveal the morphology and structure of the Manila accretionary wedge and deepen the understanding of its evolution process, several typical seismic profiles across the northern part of the Manila subduction zone are processed by depth migration and prestack depth migration profiles. Depth-velocity models are obtained, and the morphological structure and internal characteristics of the Manila accretionary wedge are also interpreted in detail. The Manila accretionary wedge can be divided into four parts:the original sedimentary segment, fold deformation segment, thrust nappe segment, and back-thrust fault segment, representing the different stages of the accretion wedge evolution. It can be inferred that a "fore arc baseplate, " which was formed by the residual part of the Philippine Sea Plate in the early obduction stage, exists under the accretionary wedge, and the fore arc baseplate is the key structure controlling the formation and evolution of the Manila accretionary wedge. The front end of the fore arc baseplate is the place where the detachment surface abruptly descends and "disappears" in the seismic section. The squeezing of the fore arc baseplate into the bottom of the accretionary wedge leads to the gradual development of out-of-sequence thrust and the continuous climbing of accretionary wedge to the fore arc baseplate, which leads to the differentiation of landform of upper and lower continental slopes of accretionary wedge and provides the main stress for the formation and deformation of the fold deformation segment and thrust nappe segment. |
| Key words: Manila trench accretionary prism fore arc baseplate decollement out-of-sequence thrust |