A Seismic Tomography, Gravity, and Flexure Study of the Crust and Upper Mantle Structure of the Emperor Seamounts at Jimmu Guyot
A Seismic Tomography, Gravity, and Flexure Study of the Crust and Upper Mantle Structure of the Emperor Seamounts at Jimmu Guyot
复制标题
DOI：
10.1029/2021jb023241
复制
发表时间：
2022-06-01
影响因子：
3.9
通讯作者：
Boston, B. B.
中科院分区：
文献类型：
--
作者：
Xu, C.;Dunn, R. A.;Boston, B. B.
夏威夷-皇帝海山链一直被认为是太平洋板块在地幔柱上运动产生的热点轨迹，是研究火山构造、岩浆供应、地幔柱-地壳相互作用、挠曲载荷和上地幔流变学的理想特征。尽管皇帝海山作为该岛链的主要组成部分非常重要，但人们对它的研究却相对较少。在本文中，我们介绍了一个有源广角反射和折射实验的结果进行了沿着海底地震仪（OBS）线定向垂直于海山链，交叉Jimmu盖奥特。层析P波速度模型，使用类似的20,000旅行时间从26个OBS，建议有一个高速（>6.0 km/s）侵入核内的机构，和挤压-侵入比估计为2.5，表明Jimmu主要是由挤压过程。在Jimmu形成期间，洋壳顶部以上岩浆物质的总体积约为5.3 x 10（4）km（3），相关体积通量约为0.96 m（3）/s。在火山负荷下，大约5.3公里厚的洋壳在一个广阔的区域内被压下大约3.8公里。使用Vp和密度之间的标准关系，通过重力模拟来验证速度模型，并且板块挠曲模拟表明有效弹性厚度（T-e）类似于14 km。最后，我们没有发现大规模的岩浆底侵下先存地壳的证据。
The intraplate Hawaiian-Emperor Seamount Chain has long been considered a hotspot track generated by the motion of the Pacific plate over a deep mantle plume, and an ideal feature therefore for studies of volcanic structure, magma supply, plume-crust interaction, flexural loading, and upper mantle rheology. Despite their importance as a major component of the chain, the Emperor Seamounts have been relatively little studied. In this paper, we present the results of an active-source wide-angle reflection and refraction experiment conducted along an ocean-bottom-seismograph (OBS) line oriented perpendicular to the seamount chain, crossing Jimmu guyot. The tomographic P wave velocity model, using similar to 20,000 travel times from 26 OBSs, suggests that there is a high-velocity (>6.0 km/s) intrusive core within the edifice, and the extrusive-to-intrusive ratio is estimated to be similar to 2.5, indicating that Jimmu was built mainly by extrusive processes. The total volume for magmatic material above the top of the oceanic crust is similar to 5.3 x 10(4) km(3), and the related volume flux is similar to 0.96 m(3)/s during the formation of Jimmu. Under volcanic loading, the similar to 5.3-km-thick oceanic crust is depressed by similar to 3.8 km over a broad region. Using the standard relationships between Vp and density, the velocity model is verified by gravity modeling, and plate flexure modeling indicates an effective elastic thickness (T-e) of similar to 14 km. Finally, we find no evidence for large-scale magmatic underplating beneath the pre-existing crust.