Westerweel Jan, Roperch Pierrick, Licht Alexis, Dupont-Nivet Guillaume, Win Zaw, Poblete Fernando, Ruffet Gilles, Swe Hnin Hnin, Thi Myat Kai, Aung Day Wa
Geosciences Rennes, CNRS, University of Rennes 1, Rennes, France.
Dept. Earth and Space Sciences, University of Washington, Seattle, United States.
Nat Geosci. 2019 Oct;12(10):863-868. doi: 10.1038/s41561-019-0443-2. Epub 2019 Sep 9.
Convergence between the Indian and Asian plates has reshaped large parts of Asia, changing regional climate and biodiversity. Yet geodynamic models fundamentally diverge on how convergence was accommodated since the India-Asia collision. Here we report paleomagnetic data from the Burma Terrane, at the eastern edge of the collision zone and famous for its Cretaceous amber biota, to better determine the evolution of the India-Asia collision. The Burma Terrane was part of a Trans-Tethyan island arc and stood at a near-equatorial southern latitude at ~95 Ma, suggesting island endemism for the Burmese amber biota. The Burma Terrane underwent significant clockwise rotation between ~80-50 Ma, causing its subduction margin to become hyper-oblique. Subsequently, it was translated northward on the Indian Plate, by an exceptional distance of at least 2000 km, along a dextral strike-slip fault system in the east. Our reconstructions are only compatible with geodynamic models involving a first collision of India with a near-equatorial Trans-Tethyan subduction system at ~60 Ma, followed by a later collision with the Asian margin.
印度板块与亚洲板块的汇聚重塑了亚洲的大部分地区,改变了区域气候和生物多样性。然而,关于自印度-亚洲碰撞以来汇聚是如何实现的,地球动力学模型存在根本分歧。在此,我们报告了来自碰撞带东部边缘、以其白垩纪琥珀生物群而闻名的缅甸地体的古地磁数据,以更好地确定印度-亚洲碰撞的演化过程。缅甸地体是特提斯洋跨洋岛弧的一部分,在约9500万年前位于近赤道的南纬地区,这表明缅甸琥珀生物群具有岛屿特有性。缅甸地体在约8000万至5000万年前经历了显著的顺时针旋转,导致其俯冲边缘变得极度倾斜。随后,它在印度板块上向北平移,沿东部的右旋走滑断层系统移动了至少2000公里的特殊距离。我们的重建结果仅与以下地球动力学模型相符:印度在约6000万年前首先与近赤道的特提斯洋俯冲系统发生碰撞,随后与亚洲边缘发生碰撞。