Khalifa University of Science and Technology, Abu Dhabi, UAE.
Department Earth Sciences, University of Oxford, South Parks Road, Oxford, OX1 3AN, UK.
Nat Commun. 2020 May 29;11(1):2671. doi: 10.1038/s41467-020-16521-0.
The Oman-United Arab Emirates ophiolite has been used extensively to document the geological processes that form oceanic crust. The geometry of the ophiolite, its extension into the Gulf of Oman, and the nature of the crust that underlies it are, however, unknown. Here, we show the ophiolite forms a high velocity, high density, >15 km thick east-dipping body that during emplacement flexed down a previously rifted continental margin thereby contributing to subsidence of flanking sedimentary basins. The western limit of the ophiolite is defined onshore by the Semail thrust while the eastern limit extends several km offshore, where it is defined seismically by a ~40-45°, east-dipping, normal fault. The fault is interpreted as the southwestern margin of an incipient suture zone that separates the Arabian plate from in situ Gulf of Oman oceanic crust and mantle presently subducting northwards beneath the Eurasian plate along the Makran trench.
阿曼-阿拉伯联合酋长国蛇绿岩被广泛用于记录形成海洋地壳的地质过程。然而，蛇绿岩的几何形状、它在阿曼湾的延伸以及它所覆盖的地壳的性质是未知的。在这里，我们表明蛇绿岩形成了一个高速、高密度、>15 公里厚的向东倾斜的物体，在就位过程中向下弯曲了一个先前裂开的大陆边缘，从而导致了侧翼沉积盆地的沉降。蛇绿岩的西部边界在陆上由赛麦尔冲断层定义，而东部边界在海上延伸数公里，在那里，地震学上由一个~40-45°、向东倾斜的正断层定义。这条断层被解释为一个初始缝合带的西南边缘，该缝合带将阿拉伯板块与阿曼湾原地海洋地壳和地幔分开，目前沿着马克兰海沟向北俯冲在欧亚板块之下。
