Oroclinal bending of the Saishitengshan arcuate belt and implications for strike-slip faulting of the Altyn Tagh Fault
Oroclinal bending of the Saishitengshan arcuate belt and implications for strike-slip faulting of the Altyn Tagh Fault
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DOI：
10.1016/j.tecto.2022.229543
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发表时间：
2022-08
期刊：
影响因子：
2.9
通讯作者：
Bingshuai Li;M. Yan;Weilin Zhang;X. Fang;Yongpeng Yang;Dawen Zhang;Chong Guan;J-X Bao
中科院分区：
文献类型：
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作者：
Bingshuai Li;M. Yan;Weilin Zhang;X. Fang;Yongpeng Yang;Dawen Zhang;Chong Guan;J-X Bao
了解阿尔金-塔格断裂(ATF)南部弧形带的起源，对于了解ATF的演化具有重要意义。本文对柴达木盆地北部赛石腾山弧形带(SAB)的两个部分进行了详细的古地磁旋转研究，以更好地了解ATF的演化。古地磁结果表明，在上干柴沟组和下油砂山组沉积过程中，两半之间存在约25°的旋转差异。这种旋转差异与SAB的几何走向变化相一致，在附近黑石丘相似旋转的基础上，进一步约束了其造山斜弯曲，认为其发生在中新世中晚期(~17-10 Ma)。结合ATF沿线的其他古地磁结果，我们认为，由于ATF的摩擦拖曳，在断裂南侧发育了一条明显逆时针旋转的过渡带，这与其在中新世中晚期由集中左旋剪切向分布左旋剪切的构造转变有关。
Knowledge regarding the origin of the arcuate belts located south of the Altyn Tagh Fault (ATF) is important for understanding the evolution of the ATF. Here, we conduct a detailed paleomagnetic rotation study on two halves of the Saishitengshan arcuate belt (SAB) in the northern Qaidam Basin to better understand the ATF evolution. Paleomagnetic results reveal an ~25° rotational difference between the two halves during deposition of the Shangganchaigou and Xiayoushashan formations. This rotational difference is consistent with the geometric trend change in the SAB, and its oroclinal bending is further constrained as having occurred during the middle to late Miocene (~17–10 Ma) based on similar rotation of nearby Heishiqiu. Combined with other paleomagnetic results along the ATF, we propose that a transitional zone with remarkable counterclockwise rotations developed south of the fault due to the frictional dragging of the ATF, which is related to its tectonic transition from concentrated to distributed sinistral shear during the middle to late Miocene.