[1]刘金平,李三忠,索艳慧,等.残生微洋块: 俯冲消减系统下盘的复杂演化[J].大地构造与成矿学,2018,(优先出版):762-778.[doi:10.16539/j.ddgzyckx.2019.04.010]
 LIU Jinping,LI Sanzhong,SUO Yanhui,et al.Subduction-derived Oceanic Micro-block: Complex Evolution of Footwall in Subduction System[J].Geotectonica et Metallogenia,2018,(优先出版):762-778.[doi:10.16539/j.ddgzyckx.2019.04.010]
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残生微洋块: 俯冲消减系统下盘的复杂演化
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《大地构造与成矿学》[ISSN:ISSN 1001-1552/CN:CN 44-1595/P]

卷:
期数:
2018年优先出版
页码:
762-778
栏目:
出版日期:
2019-12-30

文章信息/Info

Title:
Subduction-derived Oceanic Micro-block: Complex Evolution of Footwall in Subduction System
作者:
刘金平 李三忠 索艳慧 朱俊江 李玺瑶 戴黎明 刘永江 于胜尧 郭玲莉
Author(s):
LIU Jinping LI Sanzhong SUO Yanhui ZHU Junjiang LI Xiyao DAI Liming LIU Yongjiang YU Shengyao and GUO Lingli
关键词:
残生 微洋块 三节点 板块构造 俯冲消减
Keywords:
subduction-derived oceanic micro-block triple junction plate tectonics subduction
DOI:
10.16539/j.ddgzyckx.2019.04.010
文献标志码:
A
摘要:
残生微洋块, 即正在俯冲消减或俯冲停滞的原大型洋壳板块的海底残余, 位于俯冲消减系统的俯冲盘, 一般被活动或死亡的洋中脊、海沟及转换断层所围限, 但也存在例外, 如里维拉(Rivera)微洋块与科科斯(Cocos)板块的边界。现今已确认的残生微洋块有胡安?德?富卡(Juan de Fuca)、里维拉(Rivera)、瓜达卢佩(Guadalupe)等法拉隆(Farallon)板块的残余和位于南美洲和南极洲之间的菲尼克斯(Phoenix)微洋块。此类微洋块的边界以及恢复其演化过程主要是通过地形、重力异常、震源分布、磁异常条带、地震剖面和构造解释等手段辨析。洋中脊与俯冲带的相对位移使围限的洋壳板块面积整体或局部不断减小, 当整块洋壳面积减小到10万平方千米以下时形成残生微洋块, 其产生的动力机制为地幔对流驱动下的相邻板块之间的相互作用。较大的微洋块可能因新生洋壳的浮力等因素造成俯冲速度及方向的差异, 破裂为数个更小的微洋块。残生微洋块的形成和演化与洋中脊、俯冲系统、板片窗形成及三节点的转化密不可分, 研究其成因模式可为探索板块起源和动力提供参考。在板块俯冲过程中可能产生大洋汇聚边界并以此作为微洋块新的边界(如里维拉?科斯边界), 可与陆内变形带类比。
Abstract:
The micro-blocks are sometimes the precursors of large plates. The origin, growth, aborting, extinction and residual process of micro-blocks are of great significance for the study of plate tectonics. The micro-block can be divided into continental micro-block and oceanic micro-block according to its composition. By summarizing previous studies, the type characteristics and genetic model of subduction-derived oceanic micro-block (Sd-Mob) can be obtained. Sd-Mobs are the remnants of the original large oceanic plates, which are located in the heading side of the subduction system, generally surrounded by active or dead mid-ocean ridges, trenches and transform fault. Whereas, there are exceptions as Rivera-Cocos boundary. The subduction-derived oceanic micro-blocks now identified are Juan de Fuca, Rivera, Guadalupe and other blocks which are regarded as remnants of Farallon plate. In addition, the remnant of Phoenix plate between Antarctica and South America Plate has the feature of Sd-Mob. Sd-Mobs are mainly identified by boundary features. The boundary can be distinguished by means of topography, gravity anomaly, seismic source distribution, magnetic anomaly stripe, seismic profile and structural interpretation. When the relative displacement of mid-ocean ridge and subduction zone occurred, making oceanic plate area decrease to a certain extent, Sd-Mobs were formed. Large Sd-Mobs could break up into several small blocks due to factors including the buoyancy of new oceanic crust and subduction speed and direction. The dynamic mechanism is the interaction with the adjacent large plates, such as the Pacific plate and the North American plate. The formation and evolution of Sd-Mobs are inseparable from mid-ocean ridge, subduction system, the formation of slab windows and the switch of triple junctions. The study of its genesis model can provide a reference for the origin and dynamics of plates. In the process of plate subduction, an oceanic convergence boundary may be generated and used as a new boundary of a oceanic micro-block (such as the Rivera-Cocos boundary), which can be compared with the continental deformation zone.
更新日期/Last Update: 2019-08-04