洋-陆转换带类型与成因机制

发布时间：2018-06-27 22:26

本文选题：洋-陆转换带 + 火山型被动陆缘　；参考：《地学前缘》2017年04期

【摘要】：洋-陆转换带是被动陆缘的特殊构造,是伸展背景下大陆岩石圈与大洋岩石圈相互作用的关键区域,对于理解和认识大洋和大陆的地球动力过程、机制尤为关键。基于不同的被动陆缘类型,本文总结了不同类型被动陆缘的洋-陆转换带分类及特征,同时探讨其成因机制。根据大陆边缘类型,洋-陆转换带可以划分为四类,火山型被动陆缘中以海倾反射层和下地壳高速体为特征的洋-陆转换带、非火山型被动陆缘蛇纹石化地幔橄榄岩出露的洋-陆转换带、异常减薄洋壳组成的洋-陆转换带、强烈减薄陆壳为主的洋-陆转换带。洋-陆转换带成因模式取决于不同类型被动陆缘的伸展破裂过程,火山型被动陆缘起源于主动的火山裂谷,通过热作用来减薄岩石圈的底部进而发生地幔熔融,产生溢流玄武岩,浅表形成海倾反射体,下地壳表现为高P波速度异常且巨厚的高速体。非火山型陆缘的岩石圈横向伸展与深度相关,岩石圈变形既有均一纯剪切变形(均匀伸展)也有不对称的简单剪切变形(拆离断层)。
[Abstract]:The oceanic continental transition zone is a special structure of the passive continental margin. It is the key area for the interaction of the continental lithosphere and the oceanic lithosphere under the extensional background. The mechanism is particularly critical for understanding and understanding the dynamic process of the oceans and continents. Based on different passive continental types, this paper has always been divided into the oceanic and land transition zones of different types of passive continental margin. According to the continental margin type, the oceanic land transition zone can be divided into four types. The oceanic land transition zone, characterized by the sea tilting reflector and the lower crust high-speed body in the volcanic passive continental margin, and the ocean continental transition zone of the non volcanic passive continental serpentine olives and Iwade dew in the passive continental margin, and the abnormal thinning of the oceanic crust. The oceanic land transition zone strongly thins the oceanic continental transition zone, which mainly depends on the continental crust. The genesis model of the oceanic land transition zone depends on the extension and rupture process of the different types of passive continental margin. The volcanic passive continental margin originates from the active volcanic rift, and is used to reduce the bottom of the lithosphere and then to melt the mantle, producing overflow basalt and shallow form. The lower crust is characterized by a high velocity body with high P wave velocity and huge thickness. The lateral extension of the lithosphere of the non volcanic continental margin is related to the depth of the lithosphere, and the deformation of the lithosphere has both uniform pure shear deformation (uniform extension) and asymmetric simple shear deformation (detached fault).
【作者单位】：青岛海洋科学与技术国家实验室海洋地质过程与环境功能实验室;青岛海洋科学与技术国家实验室海洋地质功能实验室;
【基金】：国家自然科学基金青年基金项目(41502321);国家自然科学基金杰出青年基金项目(41325009) 山东省泰山学者特聘教授项目鳌山卓越科学家计划项目(2015ASTP-0S10)
【分类号】：P542;P736.1

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