The Cenozoic evolution of the Altyn Tagh Fault (ATF) is still under debate. Here, we present new paleomagnetic rotation evidence on curvatures south of the ATF in the northeastern Tibetan Plateau to shed new light on this issue. A total of 498 core samples representing 53 sites and 6 time intervals (a-f) were collected from the post-Oligocene sequence at the Heishiqiu locality that in the junction of the northwestern and middle of the reverse S-type northern Qaidam marginal thrust belt. Rock magnetic analysis indicated that the main magnetic carriers were hematite and magnetite. After detailed thermal demagnetization analyses, the characteristic remanent magnetizations of 48 sites (387 samples), which exhibited dual polarities and passed a regional fold test, are most likely the primary magnetizations. Two periods of remarkable rotations are identified at Heishiqiu: a clockwise rotation of ~16.0 ± 10.3° during ~27–17 Ma and a subsequent counterclockwise rotation of ~24.3 ± 14.5° during ~17–10 Ma. The rotations were attributed to two periods of strike-slip faulting along the ATF during the Early Oligocene to Late Miocene, yielding at least ~290–380 km of offset at Heishiqiu. The integrated lines of paleomagnetic and geological evidence suggest that the deformation along the ATF has propagated both southwestward and northeastward from Heishiqiu in the middle ATF since the Early Oligocene. We propose a bidirectional growth model for the ATF that might be applicable to the evolution of the Tibetan Plateau.

阿尔金断层（ATF）的新生代演化仍在争论中。在这里，我们提出了有关青藏高原东北部 ATF 以南曲率的新古地磁旋转证据，以阐明这一问题。柴达木北部逆S型边缘逆冲带西北部和中部交界处黑石球地区的后渐新世层序共采集498个岩心样品，代表53个地点和6个时间间隔（af）。岩石磁性分析表明，主要的磁性载体是赤铁矿和磁铁矿。经过详细的热退磁分析，48个位点（387个样品）的特征剩磁表现出双极性并通过了区域折叠测试，很可能是初级磁化。在黑石球确定了两个显着的旋转周期：在~27-17 Ma 期间顺时针旋转~16.0 ± 10.3°，随后在~17-10 Ma 期间逆时针旋转~24.3 ± 14.5°。旋转归因于早渐新世至晚中新世期间沿 ATF 的两个走滑断层，在黑石球产生至少约 290-380 公里的偏移。古地磁和地质证据的综合线表明，早渐新世以来，沿ATF的变形从ATF中部的黑石球向西南和东北传播。我们提出了一个可能适用于青藏高原演化的 ATF 双向增长模型。在 ~17–10 Ma 期间为 5°。旋转归因于早渐新世至晚中新世期间沿 ATF 的两个走滑断层，在黑石球产生至少约 290-380 公里的偏移。古地磁和地质证据的综合线表明，早渐新世以来，沿ATF的变形从ATF中部的黑石球向西南和东北传播。我们提出了一个可能适用于青藏高原演化的 ATF 双向增长模型。在 ~17–10 Ma 期间为 5°。旋转归因于早渐新世至晚中新世期间沿 ATF 的两个走滑断层，在黑石球产生至少约 290-380 公里的偏移。古地磁和地质证据的综合线表明，早渐新世以来，沿ATF的变形从ATF中部的黑石球向西南和东北传播。我们提出了一个可能适用于青藏高原演化的 ATF 双向增长模型。古地磁和地质证据的综合线表明，早渐新世以来，沿ATF的变形从ATF中部的黑石球向西南和东北传播。我们提出了一个可能适用于青藏高原演化的 ATF 双向增长模型。古地磁和地质证据的综合线表明，早渐新世以来，沿ATF的变形从ATF中部的黑石球向西南和东北传播。我们提出了一个可能适用于青藏高原演化的 ATF 双向增长模型。