浅谈中国大陆东缘中生代地质演化与泛太平洋板块活动的关系  

Discussion on the Relationship Between Pan Pacific Plate Movement and Mesozoic Geological Evolution of Eastern Chinese Continent

作　　者：杨海斌[1,2] 田小波[1] 白志明[1] 张中杰[1] 

机构地区：[1]中国科学院地质与地球物理研究所,北京100029 [2]吉林大学地球探测科学与技术学院,长春130026

出　　处：《吉林大学学报（地球科学版）》2016年第3期781-797,共17页Journal of Jilin University：Earth Science Edition

基　　金：国家自然科学基金项目(41274066);中国科学院地质与地球物理研究所岩石圈演化国家重点实验室项目~~

摘　　要：本文旨在厘清中生代中国东缘受泛太平洋板块俯冲作用影响下,其可能形成的地质记录的时空分布与泛太平洋板块活动的关系。前者主要从岩浆、构造、沉积盆地的时空演化等角度出发,后者的运动学参数集中在俯冲角度、速度、方向等维度。结果显示:俯冲角度、速度以及方向的改变都有可能形成与之对应的地质事件;但是中国东缘(东北、华北和华南)区域地质记录间的差异也表明,即使都可能遭受俯冲作用,由于个体特殊的构造背景,最终的结果也不尽相同。我们对于中国东缘中、新生代的这一特殊构造现象进行了讨论,得出如下结论:首先三联点力学稳定性分析结果认为,在华北和华南碰撞拼合后,中国大陆东缘可能存在TTT、TTR或者TFT的三联点,而不是简单的稳定的被动大陆边缘;另外,中国华南早、中侏罗世近东西向岩浆岩的形成可能与法拉隆板块和伊泽奈岐板块洋中脊俯冲有关;晚侏罗—早白垩世的板片后撤由NWW向的伊泽奈岐板块与太平洋板块的洋中脊扩张作用所致;而华北克拉通东部记录侏罗纪伊泽奈岐板块俯冲的证据不足,可能并没有发生板块俯冲作用,表现为板块运动与作为中国东部最为薄弱地区的郯庐断裂带的强烈耦合作用。This paper aims to reveal the relationships between the temperal-spatial distribution of geological recordings,like magmatism,structure and sedimentary basin,and the movement of Pan Pacific plate which intensively influenced the Eastern Chinese continent. As a consequence,variation of plate subducting angle,velocity and direction can produce a great impact on the continent overlying. The Eastern Chinese continent,consisting of Northeast China（ NEC）,North China（ NC） and South China（ SC）,all were influenced by the Pan Pacific plate subduction on the eastern borde. Due to their various inherent properties,different plates had experienced different geological evolution. Based on discussion on some phenomena characterized as full of anomalies,some conclusions can be drawn for further test. Firstly,through mechanical analysis of possible triple junctions ever existing in eastern China continental frontier,it is suggested that the TTT,TTR or TFT modes should work there,rather than the simplified stable passive continental boundary. Secondly,the origin of westeast distribution of magmatism in central SC might call the ridge of Farallon and Izanagi plate as a reference. The NWW-extending ridge expanding of Izanagi and Pacific could result in the backward movement of plate blocks from the Late Jurassic to Early Cretaceous. Thirdly,few evidence supports the subduction ever took place in the eastern NC,which leads to the hypothesis that the Tanlu fault,the inherent weak part of NC,could have performed as other continent margin,which can be indicated by the strong coupling of plate motion and the corresponding activities of Tanlu fault in Jurassic and Early Cretaceous,instead of plate subduction under NC.

关 键 词：中国大陆东缘 太平洋板块 板块俯冲 中、新生代 郯庐断裂 三联点 

分 类 号：P541[天文地球—构造地质学]