Surface-wave tomography of the Emeishan large igneous province (China): Magma storage system, hidden hotspot track, and its impact on the Capitanian mass extinction
Surface-wave tomography of the Emeishan large igneous province (China): Magma storage system, hidden hotspot track, and its impact on the Capitanian mass extinction
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峨眉山大型火成岩省（中国）的表面波层析成像：岩浆储存系统、隐藏的热点轨迹及其对卡皮坦大灭绝的影响
DOI：
10.1130/g49055.1
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发表时间：
2021-04
期刊：
影响因子：
5.8
通讯作者：
Yuanyuan Fu
中科院分区：
文献类型：
--
作者：
Yiduo Liu;Lun Li;Jolante van Wijk;Aibing Li;Yuanyuan Fu
大火成岩省（LIPs）通常与大规模喷发有关。然而，LIPs及其对生物多样性的影响之间的确切关系是神秘的，因为它们可以是异步的。有人提出，环境影响主要与岩床安放有关。因此，LIPs岩浆储存系统的结构至关重要，因为它决定了大灭绝的发生和时间。利用面波层析成像技术对中国西南地区峨眉山二叠纪大火成岩省（ELIP）岩石圈进行成像。在地壳和岩石圈中发现了一个高剪切波速度（Vs）和负径向各向异性（Vsv > Vsh; v和h分别为垂直和水平极化的S波）的东北向带。我们排除了裂谷或造山作用的可能性来解释这些地震特征，并将地震异常解释为ELIP的镁铁质-超镁铁质岩脉为主的岩浆储存系统。我们进一步提出，异常代表了一个隐藏的热点轨道，是安置在ELIP喷发之前。一个区域的速度较高，但较少的负径向各向异性，热点的轨道，但东北部的喷发中心在攀西地区，反映了一个升高的比例的窗台安置在初期阶段的ELIP。早期岩床侵入体释放的有毒气体解释了为什么Capitanian中期全球生物群危机比ELIP火山爆发高峰早200 - 300万年。
Large igneous provinces (LIPs) are commonly associated with mass extinctions. However, the precise relations between LIPs and their impacts on biodiversity is enigmatic, given that they can be asynchronous. It has been proposed that the environmental impacts are primarily related to sill emplacement. Therefore, the structure of LIPs’ magma storage system is critical because it dictates the occurrence and timing of mass extinction. We use surface-wave tomography to image the lithosphere under the Permian Emeishan large igneous province (ELIP) in southwestern China. We find a northeast-trending zone of high shear-wave velocity (Vs) and negative radial anisotropy (Vsv > Vsh; v and h are vertically and horizontally polarized S waves, respectively) in the crust and lithosphere. We rule out the possibilities of rifting or orogenesis to explain these seismic characteristics and interpret the seismic anomaly as a mafic-ultramafic, dike-dominated magma storage system of the ELIP. We further propose that the anomaly represents a hidden hotspot track that was emplaced before the ELIP eruption. A zone of higher velocity but less-negative radial anisotropy, on the hotspot track but to the northeast of the eruption center in the Panxi region, reflects an elevated proportion of sills emplaced at the incipient stage of the ELIP. Liberation of poisonous gases by the early sill intrusions explains why the mid-Capitanian global biota crisis preceded the peak ELIP eruption by 2–3 m.y.
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中国中二叠世的火山活动、生物大灭绝和碳同位素波动
影响因子：
56.9
作者：
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影响因子：
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通讯作者：
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