摘要
受新特提斯洋俯冲以及随后阿拉伯板块向欧亚板块斜向汇聚的影响,伊朗高原内活动构造广泛发育,且伴随有显著的陆内变形、大规模的岩浆事件以及强烈的地震活动。该区域是研究陆-陆碰撞早期阶段高原隆升演化的关键区域,构建其岩石圈精细三维结构模型将有助于深入理解新特提斯洋闭合过程及阿拉伯-欧亚板块汇聚的深部动力学机制。本文基于地震三维横波速度模型和热流模型,通过重力和地形联合反演,构建了伊朗高原地壳-上地幔尺度的高精度三维密度结构模型。结果显示,伊朗高原岩石圈密度分布存在区域性差异:萨南达季-锡尔詹变质带与乌鲁米耶-多赫塔尔岩浆弧在中上地壳存在与新特提斯洋岩石圈俯冲相关的高密度异常;南里海盆地、美索不达米亚前渊、阿拉伯板块北部、波斯湾北部和莫克兰俯冲带等区域地壳相对较薄;受阿拉伯板块向伊朗高原下方俯冲的影响,扎格罗斯造山带深部存在下插至萨南达季-锡尔詹变质带和乌鲁米耶-多赫塔尔岩浆弧下方的地壳根,且地壳向北东方向逐渐增厚。另外,阿拉伯俯冲板片断裂引起深部地幔低密度物质上涌,逐步改造了伊朗中部区域岩石圈的物质与组成,可能导致了伊朗中部区域的地壳减薄和上地幔顶部的低密度异常。
The Iranian Plateau has been influenced by the subduction of the Neo-Tethys Ocean toward the Eurasian Plate and subsequent oblique convergence of the Arabian and Eurasian plates,exhibiting widespread tectonic activities accompanied by significant intracontinental deformation,large-scale magmatic events,and intense seismic activities.This region constitutes a pivotal natural laboratory for investigating plateau uplift dynamics during the incipient stages of continent-continent collision.High-resolution three-dimensional lithospheric structure will provide critical insights into the closure processes of the Tethyan Ocean and the deep-seated dynamic mechanisms governing the convergence of the Arabian-Eurasian plates.Integrating three-dimensional shear-wave velocity model and thermal flow model,this study employs joint gravity and topography inversion to construct a high-resolution three-dimensional density structure model of the crust and upper mantle beneath the Iranian Plateau.The results show that the lithospheric density distribution of the Iranian Plateau exhibits regional heterogeneity.The Sanandaj-Sirjan Zone and Urumieh-Dokhtar magmatic arc exhibit high-density anomalies within the mid-upper crustal domains,which show genetic associations with Neo-Tethyan oceanic lithosphere subduction processes.The crustal thickness exhibits significant thinning in multiple tectonic provinces,notably including the south Caspian Basin,Mesopotamian Foredeep,northern Arabian Plate,northern Persian Gulf,and Makran Subduction Zone.Driven by the ongoing subduction of the Arabian Plate beneath the Iranian Plateau,the Zagros Orogenic Belt exhibits a crustal root that plunges beneath the Sanandaj-Sirjan Zone and Urumieh-Dokhtar magmatic arc,accompanied by progressive northeastward crustal thickening.Furthermore,the break-off of the subducted Arabian slab has likely triggered upwelling of mantle materials,progressively modifying lithospheric material and composition in the central Iran,potentially driving crustal thinning and low-density anomalies at the top of the upper mantle beneath the region.
作者
戴梦雪
裴军令
赵斐宇
侯礼富
DAI MengXue;PEI JunLing;ZHAO FeiYu;HOU LiFu(National Key Laboratory of Uranium Resources Exploration-Mining and Nuclear Remote Sensing,East China University of Technology,Nanchang 330013,China;SinoProbe Laboratory,Chinese Academy of Geological Sciences,Beijing 100094,China)
出处
《岩石学报》
北大核心
2025年第9期3165-3179,共15页
Acta Petrologica Sinica
基金
国家自然科学基金项目(42304145、42430208)
国家重点研发计划项目(2022YFC2807401)
江西省自然科学基金项目(20232BAB213077)
自然资源部深地科学与探测技术实验室开放课题(SL202412)联合资助.
