Seismic evidence for a thermochemical mantle plume underplating the lithosphere of the Ontong Java Plateau
Seismic evidence for a thermochemical mantle plume underplating the lithosphere of the Ontong Java Plateau
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DOI：
10.1038/s43247-021-00169-9
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发表时间：
2021-05-24
影响因子：
7.9
通讯作者：
Yoshimitsu, Junko
中科院分区：
文献类型：
--
作者：
Isse, Takehi;Suetsugu, Daisuke;Yoshimitsu, Junko
西太平洋的翁通爪哇高原是世界上最大的海洋高原。它是由 1.22 亿年前的一次大规模火山活动形成的，对地球环境产生了重大影响。由于对高原下方的上地幔结构知之甚少，岩浆事件的原因仍然存在争议。在这里，我们使用通过海底观测获得的被动地震数据以及现有的地震数据来确定深度达 300 公里的三维径向各向异性剪切波速度。我们发现，翁通爪哇高原中心下方的岩石圈-软流圈边界比周围海底深约 40 公里。根据我们的研究结果以及岩石学和流变学的限制，我们提出，岩石圈-软流圈边界加深是由于热化学地幔柱形成翁通爪哇高原期间，由于热化学地幔柱的作用，使预先存在的岩石圈下方的脱水残留物质底侵所致。根据分析，翁通爪哇高原下方的岩石圈相对于周围海底增厚了 40 公里，这表明它是通过地幔柱的上升形成的。海底地震观测。
The Ontong Java Plateau in the western Pacific Ocean is the world's largest oceanic plateau. It was formed 122 million years ago by a massive volcanic event that significantly affected Earth's environment. The cause of the magmatic event remains controversial because the upper mantle structure beneath the plateau is poorly known. Here we use passive seismic data obtained through seafloor observations, alongside existing seismic data, to determine the three-dimensional radially anisotropic shear wave velocity to depths of up to 300 km. We find that the lithosphere-asthenosphere boundary is approximately 40 km deeper beneath the centre of the Ontong Java Plateau than beneath the surrounding seafloor. Based on our results and petrological and rheological constraints, we propose that the lithosphere-asthenosphere boundary has deepened as a result of underplating of dehydrated residual material beneath the pre-existing lithosphere during formation of the Ontong Java Plateau by a thermochemical mantle plume.The lithosphere beneath the Ontong Java Plateau is thickened by up to 40 km relative to the surrounding ocean floor which suggests it formed through the ascent of a mantle plume, according to analyses of seafloor seismic observations.