陈建文, 许明, 雷宝华, 施剑, 刘俊. 华北-扬子板块碰撞结构的识别:来自南黄海海域的证据[J]. 海洋地质与第四纪地质, 2020, 40(3): 1-12. DOI: 10.16562/j.cnki.0256-1492.2019070902
引用本文: 陈建文, 许明, 雷宝华, 施剑, 刘俊. 华北-扬子板块碰撞结构的识别:来自南黄海海域的证据[J]. 海洋地质与第四纪地质, 2020, 40(3): 1-12. DOI: 10.16562/j.cnki.0256-1492.2019070902
CHEN Jianwen, XU Ming, LEI Baohua, SHI Jian, LIU Jun. Collision of North China and Yangtze Plates: Evidence from the South Yellow Sea[J]. Marine Geology & Quaternary Geology, 2020, 40(3): 1-12. DOI: 10.16562/j.cnki.0256-1492.2019070902
Citation: CHEN Jianwen, XU Ming, LEI Baohua, SHI Jian, LIU Jun. Collision of North China and Yangtze Plates: Evidence from the South Yellow Sea[J]. Marine Geology & Quaternary Geology, 2020, 40(3): 1-12. DOI: 10.16562/j.cnki.0256-1492.2019070902

华北-扬子板块碰撞结构的识别:来自南黄海海域的证据

Collision of North China and Yangtze Plates: Evidence from the South Yellow Sea

  • 摘要: 华北-扬子板块碰撞是中国东部中生代最重要的地质事件之一,碰撞形成了世界最大的超高压变质带秦岭-大别-苏鲁造山带。在苏鲁造山带向海域延伸部分,一直缺乏相关地球物理资料来约束碰撞造山带的深部特征。本文总结了华北-扬子板块碰撞的经典模型,根据南黄海海域最新二维地震反射资料和前人的研究成果,认为在造山带南缘南黄海盆地中,扬子板块上、下地壳发生拆离,形成类似“鳄鱼嘴式”形态,华北板块向南楔入到扬子板块之中。在区域重磁异常图中,千里岩隆起带与苏鲁造山带具有相似的重磁异常分布,认为千里岩隆起带为华北-扬子碰撞造山带在海域上的延伸;在南黄海盆地北缘二维地震剖面中,千里岩隆起与南黄海盆地具有完全不同的地震反射特征,南黄海盆地发育完整地层层序,而千里岩隆起内部反射杂乱,变形强烈。在南黄海盆地自西向东三条南北向地震剖面中,南黄海盆地与千里岩隆起带边界反射均具有南倾特征,表明扬子板块物质置于造山带之上;南黄海盆地北部烟台坳陷发育中侏罗统,约束华北-扬子碰撞所导致的挤压活动主要发生于晚三叠世。在千里岩隆起内部反射特征整体上具有背形形态,具有向北逆冲挤压特征,千里岩隆起内反射断续自南黄海盆地基底之下延伸至造山带近地表位置,形态类似于变质核杂岩从深部拆离到地表;千里岩隆起深部,在10 s深度附近可识别一系列近水平反射,具有莫霍面反射特征,莫霍面反射延伸至南黄海盆地北缘消失,推测千里岩隆起之下为华北板块地壳,而华北-扬子板块碰撞过程导致南黄海盆地之下莫霍面反射缺失。多方面的证据支持南黄海海域内扬子板块的“鳄鱼嘴式”地壳形态,以及华北板块地壳向南楔入到扬子板块地壳中。

     

    Abstract: As an important geological event in East China, the collision of the Yangtze plate and North China plate gave rise to the formation of the Sulu-Dabie orogen. This paper made a thorough review on the different collision models. Data from seismic profiles and seismic tomography support the detachment model to the Lower Yangtze region. It says that the upper crust of the Yangtze Block detached from the lower crust, just like a crocodile opened its mouth, and the North China plate fortunately wedged into it. In the Qianliyan belt there developed similar gravity and magnetic anomalies with Sulu orogen, as the extension of the Dabie-Sulu orogen. In seismic profiles, the South Yellow Sea Basin and Qianliyan Uplift Belt are different in reflection characteristics. There are complete stratigraphic reflections in the basin but no obvious reflections in the uplift. All the boundaries show a south-dipping reflection patterns, suggesting the obduction of the Yangtze Block. The collision and derived compression mainly happened in Triassic while the growth strata deformation formed in lower Jurassic. In the lower crust of the Qianliyan Uplift, the Moho reflection is recognized at ~10 s, and disappeared below the South Yellow Sea Basin. It is thus speculated that the lower crust under the Qianliyan Uplift belong to the North China Plate, and the collision between Yangtze and North China caused the fading out of the Moho reflection. Generally, the geophysical data from the South Yellow Sea support the hypothesis that the North China Block wedged into the crocodile mouth of the Yangtze Block.

     

/

返回文章
返回