Basement Structures Have Crucial Influence on Rift Development: Insights From the Jianghan Basin, Central China
Basement Structures Have Crucial Influence on Rift Development: Insights From the Jianghan Basin, Central China
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DOI：
10.1029/2019tc005671
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发表时间：
2020-01
期刊：
影响因子：
4.2
通讯作者：
Lulu Wu;L. Mei;D. Paton;Yunsheng Liu;Chuanbo Shen;Zhaoqian Liu;Jin Luo;Caizheng Min;Minghua Li;Hui Wen
中科院分区：
文献类型：
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作者：
Lulu Wu;L. Mei;D. Paton;Yunsheng Liu;Chuanbo Shen;Zhaoqian Liu;Jin Luo;Caizheng Min;Minghua Li;Hui Wen
地壳非均质性对裂谷发育有根本影响；然而，人们对结晶基底内部构造的详细结构知之甚少，导致基底构造控制裂谷发育的确切方式相当神秘。江汉盆地是在一个覆盖着厚厚的地层的结晶基底上形成的，这为解开这个谜提供了绝佳的机会。结合江汉盆地大量的二维和三维地震、钻孔和野外资料，研究了基底构造的变形特征，并揭示了它们与上覆裂谷盆地的关系。江汉盆地基底构造最显著的特征是，上盘主要断平面附近的断陷地层比下盘的断陷地层年龄更大，而且上盘大部分断层的断陷地层在接近断平面时年龄越来越大，这表明这些断陷断层通过负构造反转重新激活了先前存在的逆冲或与无顶褶皱相关的逆冲。与典型的正常断层相比，所有与裂谷相关的主要断层都具有非常高的Dmax/L比率（0.11-0.66），这可能是由等长断层模型或低摩擦强度造成的。通过对江汉盆地基底构造的前期变形强度和构造划分的揭示，提出基底构造不仅对裂谷几何形态有重要影响，而且控制着裂谷的定位。江汉盆地多向基底构造的重新激活和多向伸展与裂谷定位，为三方裂谷系统的发育提供了尚未被认识的新见解。
Crustal heterogeneity has a fundamental influence on rift development; however, the detailed architecture of structures within crystalline basement is commonly poorly understood, resulting in the exact manner in which basement structures control rift development being rather enigmatic. The Jianghan Basin evolved on a crystalline basement covered by thick prerift strata, providing an excellent opportunity to unravel the enigma. Using extensive 2‐D and 3‐D seismic, borehole and field data from the Jianghan Basin in combination, we investigate the deformation characteristics of basement structures and unravel their relationship with the overlying rift basin. A most striking feature of the basement structures in the Jianghan Basin is that prerift strata near the major rift‐related fault planes in the hanging walls are older than these in the footwalls and for most faults prerift strata in the hanging walls become increasingly older while approaching the fault planes, suggesting that these rift‐related faults have reactivated preexisting thrusts or thrusts associated with unroofed folds through negative structural inversion. All the major rift‐related faults have very high Dmax/L ratios (0.11–0.66) compared to typical normal faults, likely resulting from either constant length fault model or low frictional strength. By unraveling the prerift deformation intensity and structural division of basement structures in the Jianghan Basin, we propose that basement structures not only have crucial influence on rift geometry but also control rift localization. The reactivation of multidirectional basement structures and multidirectional extension with rift localization in the Jianghan Basin provides yet unrecognized insights into the development of tripartite rift systems.