Andean-type retro-arc foreland system beneath northwest South China revealed by SINOPORBE profiling
Andean-type retro-arc foreland system beneath northwest South China revealed by SINOPORBE profiling
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SINOPORBE剖面揭示华南西北地区安第斯型弧后前陆系统
DOI：
10.1016/j.epsl.2018.03.008
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发表时间：
2018
影响因子：
5.3
通讯作者：
Xin Yujia
中科院分区：
文献类型：
--
作者：
Li Jianhua;Dong Shuwen;Cawood Peter;Zhao Guochun;Johnston Stephen;Zhang Yueqiao;Xin Yujia
华南中生代处于亚洲板块与太平洋板块会聚边缘的沿着，是研究弧后环境中变形、沉积和岩浆作用相互作用的理想实验室。沿着1600 km长的SINOPROBE深地震反射剖面显示了华南西北部的地壳结构，自东向西揭示：（1）扬子褶皱带上地壳高度褶皱和截断的反射层，与薄皮和厚皮逆冲系统相对应，记录了大规模的板内构造叠瓦和缩短;（2）地壳尺度的平-坡-平构造，称为主扬子滑脱构造，它形成了一个弱的粘性层，以适应薄皮和厚皮系统中的应变解耦和物质输运;（3）四川盆地的近平反射层，支持盆地为弱变形沉积中心的解释。扬子褶皱带和四川盆地是一个距离陆缘岩浆弧800 km以上的弧后前陆盆地系统。我们认为，整个弧和弧后系统的构造过程，包括弧岩浆爆发，盆地沉积，弧后逆冲传播，岩石圈俯冲，根下沉，和伸展相关的岩浆活动是相互关联的，并受质量转移。年龄数据和地质关系将构造过程与俯冲的古太平洋板块演化的地球动力学联系起来。
In the Mesozoic, South China was situated along the convergent margin between the Asian and Pacific plates, providing an excellent laboratory to understand the interactions between deformation, sedimentation and magmatism in a retroarc environment. The crustal architecture of northwest South China is displayed along the ∼600-km-long SINOPROBE deep seismic reflection profiles and reveals from east to west: (1) highly folded and truncated reflectors in the upper crust of the Yangtze Fold Zone, which correspond to thin- and thick-skinned thrust systems, and document large-scale intraplate structural imbrication and shortening; (2) a crustal-scale flat-ramp-flat structure, termed the Main Yangtze decollement, which forms a weak, viscous layer to accommodate strain decoupling and material transport in the thin- and thick-skinned systems; and (3) nearly flat-lying reflectors in the Sichuan Basin, which support interpretation of the basin as a weakly deformed depocentre. The Yangtze Fold Zone and the Sichuan Basin represent a retro-arc foreland basin system that is >800 km away from the continental-margin magmatic arc. We suggest that tectonic processes across the arc and retro-arc systems, including arc magma flare-up, basin sedimentation, retroarc thrust propagation, lithosphere underthrusting, root foundering, and extension-related magmatism were interrelated and governed mass transfer. Age data and geological relations link the tectonic processes to evolving geodynamics of the subducting Paleo-Pacific plate.