Interactions between large-scale strike-slip intersecting faults: Implication from the Tan-Lu and Xiangfan-Guangji fault zones in eastern China
Interactions between large-scale strike-slip intersecting faults: Implication from the Tan-Lu and Xiangfan-Guangji fault zones in eastern China
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大规模走滑相交断裂相互作用:来自中国东部郯庐断裂带和襄樊—广济断裂带的启示
DOI：
10.1080/00206814.2021.2010135
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发表时间：
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影响因子：
2.6
通讯作者：
Hu Huifeng
中科院分区：
文献类型：
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作者：
Zhao Tian;Zhu Guang;Ye Jin;Xu Zhengyan;Xiang Biwei;Gu Chengchuan;Li Yunjian;Luo Ruobing;Dai Chengran;Hu Huifeng
大型走滑断裂带（TLFZ）和襄樊-广济断裂带（XGFZ）均以近90°角终止于大别造山带的东南角，该角为理解大型走滑断裂终止机制提供了一个很好的天然实验室。我们提出了新的地质年代学和结构数据的XGFZ的东南端和TLFZ的西南端。NW-SE走向的XGFZ记录了其西北段的韧性剪切，其特征是在350-400°C的温度下形成的离散右旋剪切带，如石英c轴组构和显微结构所示。在XGFZ的东南段，WNW-ESE方向的逆冲断层显示。北东-南西向TLF带的特征是潜山-桐城段为离散的北东-南西向左旋韧性剪切带，太湖-潜山段为脆性左旋走滑断裂，并向太湖以南逆冲。这些逆冲断层的走向由NE-SW向ENE-WSW和E-W逐渐向南变化。新的锆石U-Pb定年结果和以前的冷却黑云母40 Ar/39 Ar年龄将XGFZ的剪切时代限制在112-102 Ma（早白垩世晚期），这与TLFZ的断裂时代（110-102 Ma）相同。大型走滑TLFZ和XGFZ都终止于其尖端的逆冲断层。我们认为，这两个断层之间的相互作用导致运动学的变化，从走滑逆冲，这起着重要的控制这两个大型交叉走滑断层的终止。XGFZ的NW-SE向右旋剪切、TLFZ的NE-SW向左旋剪切以及近东西向逆冲断层都表明中国东部早白垩世晚期存在大陆尺度的南北向挤压。这种挤压作用是古太平洋板块向北西西方向快速斜向俯冲的结果。
The large-scale strike-slip Tan–Lu Fault Zone (TLFZ) and Xiangfan–Guangji Fault Zone (XGFZ) both terminate in the southeastern corner of the Dabie Orogen at an angle of almost 90°, and this corner therefore provides a very good natural laboratory for understanding the mechanism by which large-scale strike-slip faults terminate. We present new geochronological and structural data for the southeastern tip of the XGFZ and the southwestern tip of the TLFZ. The NW–SE-striking XGFZ records ductile shearing in its northwestern segment, characterized by discrete dextral shear zones that formed at temperatures of 350–400°C, as indicated by quartz c-axes fabrics and microstructures. In the southeastern segment of the XGFZ, WNW–ESE-trending thrusts are displayed. The NE–SW-striking TLFZ is characterized by discrete NE–SW-trending sinistral ductile shear zones in the Qianshan–Tongcheng segment, brittle left-lateral strike-slip faults in the Taihu–Qianshan segment, and thrusts to the south of Taihu. The trends of these thrusts change progressively southward from NE–SW to ENE–WSW and E–W. New zircon U–Pb dating results and previous cooling biotite40Ar/39Ar ages constrain the timing of shearing in the XGFZ to 112–102 Ma (late Early Cretaceous), which is the same as the age of faulting in the TLFZ (110–102 Ma). The large-scale strike-slip TLFZ and XGFZ both terminate at their tips as thrusts. We suggest that interactions between the two faults led to the kinematic changing from strike-slip to thrusting, with this playing an important role in controlling the termination of these two large-scale intersecting strike-slip faults. The dextral shearing of the NW–SE-trending XGFZ, the sinistral shearing of the NE–SW-trending TLFZ, and the nearly E–W-trending thrust faults all indicate continental-scale N–S compression in eastern China during the late Early Cretaceous. This compression resulted from rapid NNW-ward oblique subduction of the Paleo-Pacific Plate.