One line on the map: A review of the geological history of the Semail Thrust, Oman-UAE mountains
One line on the map: A review of the geological history of the Semail Thrust, Oman-UAE mountains
复制标题
DOI：
10.1016/j.jsg.2022.104594
复制
发表时间：
2022-05
影响因子：
3.1
通讯作者：
M. Searle;M. Rioux;J. Garber
中科院分区：
文献类型：
--
作者：
M. Searle;M. Rioux;J. Garber
位于阿曼-阿联酋山脉的塞梅尔冲断构造沿着塞梅尔蛇绿岩的基底绘制，塞梅尔蛇绿岩是一个10-15 km厚的森诺曼洋壳和上地幔序列，从东北到西南侵位到阿曼先前被动的中二叠世至森诺曼大陆边缘。Semail蛇绿岩与一系列来自不同深度的不同岩石类型并置，表明这一主要断层和剪切带具有复杂的构造历史。在这里，我们总结了以前的工作，并提出了一个概述的构造历史的断层。在地质图上，塞梅尔逆冲断层沿着蛇绿岩基底被绘制为一条单线，但它涵盖了各种各样的结构特征，深度为40-45 km，时间尺度为1996 Ma（或更早）至始新世。塞梅尔逆冲断层的构造演化包括：（a）隆起的大洋俯冲带的顶板断层或韧性剪切带（B）深地幔韧性剪切带（条带状超基性岩单元），（c）位于前陆褶皱冲断带之上的脆性断层，（d）一个不连续的脆性断层，在较深的下地壳麻粒岩之上挖出较高的蛇绿岩逆冲席（例如Bani Hamid，UAE），（e）晚期的非层序逆冲断层截断了下面的构造单元（例如Hawasina Window），（f）在折返高压岩石下的被动顶板断层（例如，麝香橄榄岩下方、鲁维混杂岩和北方Saih Hatat高压岩上方的“塞梅尔逆冲断层”），以及（g）一个重新活动的正断层，它包围着上升的下盘顶点，特别是杰贝勒阿赫达尔、杰贝勒纳赫勒和赛哈塔特背斜。从沿着阿曼山脉的不同地区可以绘制出塞梅尔逆冲断层演化的不同阶段并加以解释。
The Semail Thrust in the Oman-UAE mountains is mapped along the base of the Semail Ophiolite, a 10–15 km thick sequence of Cenomanian oceanic crust and upper mantle emplaced from NE to SW onto the previously passive, Mid-Permian to Cenomanian continental margin of Oman. The juxtaposition of the Semail ophiolite with a range of different rock types sourced from different depths suggest a complex tectonic history for this major fault and shear zone. Here we summarize previous work and present an overview of the tectonic history of the fault. The Semail Thrust is mapped along the base of the ophiolite as a single line on the geological map, yet it covers a variety of structural features spanning depths of 40–45 km to the surface, and a time scale from ∼96 Ma (or earlier) to Eocene time. The structural evolution of the Semail Thrust includes (a) the roof fault or ductile shear zone of an exhumed oceanic subduction zone (granulites, amphibolites and greenschists of the metamorphic sole), (b) a deep mantle ductile shear zone (Banded Ultramafic Unit), (c) a brittle fault above a foreland-directed fold-thrust belt, (d) an out-of-sequence brittle fault exhuming a higher ophiolite thrust sheet above deeper level lower crust granulites (e.g. Bani Hamid, UAE), (e) a late out-of-sequence thrust truncating underlying structural units (e.g. Hawasina Window), (f) a passive roof fault beneath exhuming HP rocks (e.g. ‘Semail Thrust’ below the Muscat peridotite, above the Ruwi mélange and high-pressure rocks of northern Saih Hatat), and (g) a reactivated normal fault bounding rising footwall culminations, notably of the Jebel Akhdar, Jebel Nakhl, and Saih Hatat anticlines. Different stages in the evolution of the Semail Thrust can be mapped out and interpreted from different regions along the Oman Mountains.