The Late Cretaceous obduction of the Semail Ophiolite onto the rifted passive Arabian margin and the Cenozoic collisional tectonics with the final closure of the Neo-Tethys Ocean, are major contributors to the present-day crustal architecture of the northern United Arab Emirates (UAE). We acquired the first 3D grid magnetotelluric observations from 73 stations in the northern UAE in order to image deep crustal electrical structures associated with the two significant compressional episodes. Inversion of the broadband magnetotelluric data reveals the subsurface geometry of the high-resistivity ophiolite blocks, the underlying conductive thrust sheet (Haybi-Hawasina nappe), a “wedge-shaped” conductive foreland basin flanking the Hajar mountain ranges, and at depth, a high-resistivity structure associated with a fold-thrust belt adjacent to the allochthonous units, or Proterozoic crystalline basement. The ophiolite along the eastern coast (from cities Khor Fakkan to Fujairah) is more than 20 km thick and dips eastward. Across the Wadi Ham fault, the resistive ophiolite lies against less resistive materials that may represent Bani Hamid metamorphic rocks. The thin-skinned thrust sheets of the proximal-distal Tethyan sedimentary units (Haybi-Hawasina complexes) exhibit low resistivity in the Dibba zone. In contrast to its gently east-dipping geometry in the Dibba zone, the conductive Haybi-Hawasina structure in the southern portion of the study area appears nearly vertically (>20 km) beneath the dense Khor Fakkan and Aswad ophiolite blocks. This result suggests extensive deformation of the thrust sheets beneath the southerly dense ophiolite blocks.

中文翻译：

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阿拉伯东北板块晚白垩世蛇绿岩放置和新生代碰撞构造：来自新的宽带大地电磁数据的见解


晚白垩世 Semail 蛇绿岩俯冲到裂谷的被动阿拉伯边缘，以及新生代碰撞构造与新特提斯洋最终关闭，是阿拉伯联合酋长国 （UAE） 北部今天地壳结构的主要贡献者。我们从阿联酋北部的 73 个站点获得了第一个 3D 网格大地电磁观测数据，以便对与两次重要压缩事件相关的深层地壳电结构进行成像。宽带大地电磁数据的反演揭示了高电阻率蛇绿岩块的地下几何形状、下面的导电推力片 （Haybi-Hawasina nappe）、位于 Hajar 山脉两侧的“楔形”导电前陆盆地，以及在深处，与异速单元相邻的褶皱逆冲带或元古代结晶基底相关的高电阻率结构。东海岸（从 Khor Fakkan 市到富查伊拉市）的蛇绿岩厚度超过 20 公里，并向东倾斜。在 Wadi Ham 断层中，电阻蛇绿岩位于阻力较小的材料上，这些材料可能代表 Bani Hamid 变质岩。近端-远端 Tethyan 沉积单元（Haybi-Hawasina 杂岩）的薄皮逆冲片在 Dibba 区表现出低电阻率。与在 Dibba 区缓东倾斜的几何形状相反，研究区南部的导电 Haybi-Hawasina 结构几乎垂直（>20 公里）出现在密集的 Khor Fakkan 和 Aswad 蛇绿岩块下方。这一结果表明，在南向致密的蛇绿岩块体下，逆冲片发生了广泛的变形。