Abstract The magnitude and timing of deformation in the form of vertical-axis rotation in the eastern Tibetan Plateau and Southeast Asia during the Cenozoic period are the key to understanding the India-Asia collision and subsequent geological processes. Our new paleomagnetic and geochronological data from Myanmar show that the characteristic remanent magnetization (ChRM) mean directions of sedimentary tuffaceous layers (31 effective specimens) and rhyolites (11 paleomagnetic site-mean directions), which formed at ∼64.4 Ma and ∼26.6 Ma, were D±ΔD/I±ΔI = 50.8°±11.0°/33.1°±9.2° with α95 = 9.2° and D±ΔD/I±ΔI = 356.8°±6.5°/16.9°±6.2° with α95 = 6.2°, respectively. These data indicate that the West Burma Block (WBB) has experienced a significant clockwise rotation of 38.3°±6.9° since ∼64.4 Ma and a later counterclockwise rotation of 14.6 ± 4.2° since ∼26.6 Ma with respect to stable Asia. The clockwise rotation of ∼40° of the WBB since 64.4 Ma (early Paleocene) with respect to stable Asia is attributable to the India-Asia collision, and the later counterclockwise rotation of 14.6°±4.2° since 26.6 Ma (late Oligocene) is attributable to the dextral-slip faulting activity of the Sagaing Fault. These paleomagnetic analyses, combined with previously published geological research in SE Asia, are substantially consistent with the predictions of the extrusion model for the SE Asia realm.

中文翻译：

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古地磁揭示印亚碰撞期间及之后的西缅甸地块运动学演化

摘要 青藏高原东部和东南亚新生代垂直轴旋转形变的幅度和时间是理解印亚碰撞及后续地质过程的关键。我们来自缅甸的新古地磁和地质年代学数据表明，形成于~64.4 Ma和~26.6 Ma的沉积凝灰质层（31个有效标本）和流纹岩（11个古地磁场地平均方向）的特征剩磁（ChRM）平均方向，分别为 D±ΔD/I±ΔI = 50.8°±11.0°/33.1°±9.2°，α95 = 9.2°，D±ΔD/I±ΔI = 356.8°±6.5°/16.9°±6.2°，α95 = 6.2° ， 分别。这些数据表明，西缅甸地块（WBB）自~64.4 Ma以来经历了38.3°±6.9°的显着顺时针旋转，随后逆时针旋转了14.6±4。相对于稳定的亚洲，自~26.6 Ma 以来的 2°。自 64.4 Ma（早古新世）以来，WBB 顺时针旋转 40° 相对于稳定的亚洲归因于印度-亚洲碰撞，后来自 26.6 Ma（晚渐新世）逆时针旋转 14.6°±4.2°是归因于实皆断层的右旋断层活动。这些古地磁分析与之前发表的东南亚地质研究相结合，与东南亚地区挤压模型的预测基本一致。6 Ma（渐新世晚期）归因于实皆断层的右旋滑移活动。这些古地磁分析与之前发表的东南亚地质研究相结合，与东南亚地区挤压模型的预测基本一致。6 Ma（渐新世晚期）归因于实皆断层的右旋滑移活动。这些古地磁分析与之前发表的东南亚地质研究相结合，与东南亚地区挤压模型的预测基本一致。