延生型微板块成因机制模拟研究进展

Genetic Mechanism of the Propagation-derived Microplate: A Review

延生型微板块是指海底扩张或大陆裂解过程中,因裂谷间快速叠接拓展而发生旋转,捕获老的岩石圈并增生新的岩石圈所形成的一类微板块。影响其形成的动力因素众多,根据作用位置可分为浅部动力因素和深部动力因素两类。延生型微板块广泛分布于深海大洋,代表区域为东太平洋海隆处,但因观测困难,生长周期长,数据缺乏,目前对其成因机制的研究主要有物理模拟和数值模拟两类。物理模拟实验根据实验材料和设备的不同可分为冻蜡模型、离心机模型和胶体模型三种。建立的数值模型从最初简单的二维模型发展到条件更为复杂的三维模型,同时开始更多的考虑深部地幔对流的影响。但这些研究主要是探索裂谷拓展行为,仅局限于发现了延生型微板块的形成,并未形成关于延生型微板块形成和演化的研究体系。本文在前人研究的基础上归纳了延生型微板块形成的影响因素,系统梳理了相关的构造物理实验和数值模型研究问题,并结合其他相关研究进一步展望了未来建立延生型微板模型的发展方向。

The propagation-derived microplate refers to a kind of microplate formed by rapid overlapping propagation of rift during seafloor spreading or continental breakup,during which the propagation-derived microplate rotates,captures the old lithosphere,and accelerates the new lithosphere.Many dynamic factors may influence its formation,which can be divided into shallow and deep dynamic factors according to the position of action.Propagation-derived microplate is widely distributed in the deep ocean,and one of the representative areas is the East Pacific Ridge(EPR).However,due to observation difficulty,long growth cycle,lack of data,the current research methods of its genetic mechanism mainly include two types:analog modeling and numerical modeling.According to different experimental materials and equipments,the analogue modeling experiments can be divided into three types:freezing wax model,centrifuge model and colloid model.The established numerical model is developed from the initial simple two-dimensional model to the more complicated three-dimensional model,and more consideration is given to the impact of deep mantle convection.These studies are mainly focused on the propagation behavior of the rift,and did not form a systematic research system for the formation and evolution of the propagation-derived microplate.Based on previous studies,this paper summarizes the influencing factors of propagation-derived microplates,systematically reviews the related physical simulation experiment and numerical model researches,and prospects the future development direction of the propagation-derived microplate model.