Crustal intrusion beneath the Louisville hotspot track
Crustal intrusion beneath the Louisville hotspot track
复制标题
DOI：
10.1016/j.epsl.2009.11.020
复制
发表时间：
2010-01-31
影响因子：
5.3
通讯作者：
Peirce, C.
中科院分区：
文献类型：
--
作者：
Contreras-Reyes, E.;Grevemeyer, I.;Peirce, C.
我们在这里报告的第一个详细的2D断层图像的地壳和上地幔结构的白垩纪海山，在相互作用的太平洋板块和路易斯维尔热点。结果表明，在海山顶下约1.5公里处，火山机构的核心似乎主要是侵入的，速度超过6.5公里/秒。这些沉积物覆盖在高的下地壳（>7.2-7.6 km/s）和上地幔（>8.3 km/s）速度之上，表明超镁铁岩是作为岩床侵入的，而不是地壳下的底侵。结果表明，壳内岩浆侵入与喷出火山作用的体积比高达4.5左右。此外，莫霍面反射的反演显示，太平洋洋壳已向下弯曲，最高可达海山之下2.5公里。这种弯曲可以用弹性板模型来解释，在该模型中，海山侵位在加载时相当于1000万年的海洋岩石圈上。地壳内岩浆侵入可能是年轻、热的海洋岩石圈热点火山活动的一个特征，而在已有莫霍面下方的岩浆底侵可能更可能发生在热点与数千万年前的海洋岩石圈相互作用的地方。(C)2009 Elsevier B. V.保留所有权利。
We report here the first detailed 2D tomographic image of the crust and upper mantle structure of a Cretaceous seamount that formed during the interaction of the Pacific plate and the Louisville hotspot. Results show that at similar to 1.5 km beneath the seamount summit, the core of the volcanic edifice appears to be dominantly intrusive, with velocities faster than 6.5 km/s. The edifice overlies both high lower crustal (>7.2-7.6 km/s) and upper mantle (>8.3 km/s) velocities, suggesting that ultramafic rocks have been intruded as sills rather than underplated beneath the crust. The results suggest that the ratio between the volume of intra-crustal magmatic intrusion and extrusive volcanism is as high as similar to 4.5. In addition, the inversion of Moho reflections shows that the Pacific oceanic crust has been flexed downward by up to similar to 2.5 km beneath the seamount. The flexure can be explained by an elastic plate model in which the seamount emplaced upon oceanic lithosphere that was similar to 10 Myr at the time of loading. Intra-crustal magmatic intrusion may be a feature of hotspot volcanism at young, hot, oceanic lithosphere, whereas, magmatic underplating below a pre-existing Moho may be more likely to occur where a hotspot interacts with oceanic lithosphere that is several tens of millions of years old. (C) 2009 Elsevier B.V. All rights reserved.