High-resolution Lithospheric Structure of the Zagros Collision Zone and Iranian Plateau
High-resolution Lithospheric Structure of the Zagros Collision Zone and Iranian Plateau
复制标题
扎格罗斯碰撞带和伊朗高原的高分辨率岩石圈结构
DOI：
10.1002/essoar.10511688.1
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发表时间：
2022
期刊：
影响因子：
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通讯作者：
Ahmadzadeh Irandoust M
中科院分区：
文献类型：
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作者：
Ahmadzadeh Irandoust M
通过对基模瑞利波群速度和P波接收函数的联合分析，我们得到了伊朗高原地壳和上地幔的一个新的、高分辨率的三维剪切波速度（Vs）模型。最厚的地壳（>55 km）位于Sanandaj-锡尔扬带和Alborz-Binalud-Kopet Dag山脉变形带下方，而地形/变形较低的区域（例如，伊朗中部和卢特地块），以及较年轻的变形区域，如马克兰增生楔和扎格罗斯简单褶皱带（SFB），地壳较薄（<45 km）。我们的模型揭示了一个低Vstongue形状的特征，表明伊朗中部下方的阿拉伯地壳的俯冲。在扎格罗斯岛中部，阿拉伯地壳的下冲作用更为陡峭，导致变形区较窄（约150公里），地壳较厚（约60-65公里），而在扎格罗斯岛西北部或东南部，变形区较宽（约250公里），地壳较薄（约55-60公里）。上地壳中的低V区域对应于厚沉积物区域;南里海盆地，扎格罗斯SFB和扎格罗斯的前陆盆地，以及马克兰俯冲楔。高原地壳下瑞利波方位各向异性表现出相当均匀和平滑变化的模式。在西北扎格罗斯，地壳和地壳下的各向异性模式与先前根据剪切波核心相位估计的模式一致，这意味着整个岩石圈的变形是一致的，但对于其他地区（例如，西部Alborz和Kopet Dag），各向异性图案不支持整个岩石圈的连贯变形组构。
From a joint analysis of fundamental mode Rayleigh wave group velocities andP‐wave receiver functions, we derive a new, high‐resolution 3D shear‐wave velocity (Vs) model for the crust and uppermost mantle of the Iranian Plateau. The thickest crust (>55 km) is located beneath the Sanandaj‐Sirjan Zone and the deforming belts of Alborz‐Binalud‐Kopet Dag Mountains, whereas regions of lower topography/deformation (e.g., central Iran and the Lut Block), and the regions of younger deformation such as the Makran Accretionary Wedge and the Zagros Simply Folded Belt (SFB) have a thinner (<45 km) crust. Our model reveals a low‐Vstongue‐shaped feature, indicating the underthrusting of the Arabian crust beneath central Iran. In the central Zagros, the underthrusting of the Arabian crust is steeper, resulting in a narrower deforming zone (∼150 km) and a thicker crust (∼60–65 km), compared to the NW or SE Zagros where the deforming zone is broader (∼250 km) and the crust is thinner (∼55–60 km). Regions of low‐Vsin the upper crust correspond to regions of thick sediments; the South Caspian Basin, the Zagros SFB and foreland basin of the Zagros, and the Makran Subduction Wedge. The subcrustal Rayleigh wave azimuthal anisotropy of the Plateau shows a rather uniform and smoothly‐varying pattern. In the NW Zagros the crustal and subcrustal pattern of anisotropy agrees with that previously estimated from the shear‐wave core phases, implying that the whole lithosphere deforms coherently, but for other regions (e.g., the western Alborz and Kopet Dag), the anisotropic pattern does not support a coherent deformational fabric throughout the lithosphere.