Northwest Pacific-Izanagi plate tectonics since Cretaceous times from western Pacific mantle structure
Northwest Pacific-Izanagi plate tectonics since Cretaceous times from western Pacific mantle structure
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DOI：
10.1016/j.epsl.2022.117445
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发表时间：
2022-04
影响因子：
5.3
通讯作者：
Jonny Wu;Yi-An Lin;N. Flament;Jeremy Tsung Jui Wu;Yiduo Liu
中科院分区：
文献类型：
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作者：
Jonny Wu;Yi-An Lin;N. Flament;Jeremy Tsung Jui Wu;Yiduo Liu
西北太平洋Izanagi俯冲历史沿着欧亚大陆的制约很差，由于广泛的俯冲，部分消耗了西太平洋板块和整个Izanagi板块，其假设的共轭边缘。在这里，我们重建自白垩纪以来的西北太平洋Izanagi板块构造映射和结构恢复（即展开）俯冲的西太平洋板块从区域和全球层析成像，并重新创建消失的Izanagi板块作为其共轭裂谷侧翼。展开的西太平洋板块的横截面积的基础上，校正“层析涂抹”，揭示了2230至5000公里的西太平洋板块之间的堪察加半岛和马里亚纳群岛南部俯冲。我们将我们恢复的西太平洋和伊那木板块加入到全球板块模型中，揭示了中白垩纪后欧亚大陆下的伊那木俯冲仅限于现在的渤海湾-黄海、中国和北方俄罗斯之间。Izanagi俯冲的南界是一个NW-SE向的左旋转换，在中国青岛附近包裹欧亚大陆，并在晚白垩世将欧亚大陆东部的大陆岩浆活动分段，我们称之为“青岛线”。我们重建了渤海湾-黄海与俄罗斯北方之间的一个低角度Izanagi-太平洋洋脊-海沟与欧亚大陆的交汇点，时间为250 ± 10 Ma。1.50 Ma太平洋板块运动变化，引发了沿着青岛线的俯冲转换，形成伊豆-小笠原-马里亚纳岛弧，重组了渤海湾-黄海断裂。我们的层析成像和地球动力学模拟证据表明，一个4000公里长，横向连续，东北-西南走向，地震缓慢的“板间隙”在1000 ± 250公里的深度之间，目前北方库页岛和中国中部是断层的俯冲Izanagi太平洋脊的签名。
Northwest Pacific-Izanagi subduction histories along Eurasia are poorly constrained due to extensive subduction, which partially consumed the western Pacific plate and the entire Izanagi plate, its hypothesized conjugate margin. Here we reconstruct NW Pacific-Izanagi plate tectonics since Cretaceous times by mapping and structurally restoring (i.e. unfolding) the subducted western Pacific slabs from regional and global tomography, and re-creating the vanished Izanagi plate as its conjugate rift flank. Unfolding of the western Pacific slabs based on their cross-sectional areas, corrected for ‘tomographic smearing’, reveals that 2230 to 5000 km of western Pacific plate was subducted between Kamchatka and the southern Marianas. We add our restored western Pacific and Izanagi plates to a global plate model to reveal that Izanagi subduction under Eurasia after the mid-Cretaceous was limited between the present Bohai Bay-Yellow Sea, China, and northern Russia. The southern limit of Izanagi subduction was a NW-SE sinistral transform that intersected Eurasia near present Qingdao, China, and segmented eastern Eurasia continental magmatism during the late Cretaceous; we call this transform the ‘Qingdao line’. We reconstruct a low-angle Izanagi-Pacific ridge-trench intersection with Eurasia at ∼50 ± 10 Ma between Bohai Bay-Yellow Sea and northern Russia. The ∼50 Ma Pacific plate motion change initiated subduction along the Qingdao line transform, forming the Izu-Bonin-Marianas arcs and reorganizing the Bohai Bay-Yellow Sea faults. We show tomographic and geodynamic modeling evidence that a 4000 km-long, laterally-continuous, NE-SW trending, seismically-slow ‘slab gap’ at 1000 ± 250 km depth between present northern Sakhalin and central China is the tomographic signature of the subducted Izanagi-Pacific ridge.