New rates of western Pacific island arc magmatism from seismic and gravity data
New rates of western Pacific island arc magmatism from seismic and gravity data
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DOI：
10.1016/s0012-821x(02)00761-6
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发表时间：
2002-08-30
影响因子：
5.3
通讯作者：
Mochizuki, K
中科院分区：
文献类型：
--
作者：
Dimalanta, C;Taira, A;Mochizuki, K
为了研究大陆地壳的演化，人们进行了大量的研究。有些人认为，促成大陆地壳生长的机制之一是弧岩浆作用。正是在这种背景下，Reymer和Schubert（构造学3(1984)63）估计了大陆地壳的弧岩浆添加速率。他们的结果表明，岛弧岩浆活动产生物质的平均速率为20-40 km/ km/Myr（沿岛弧走向方向每单位宽度体积）。本研究利用了最新的全球海洋重力数据，以及西太平洋地区一些海洋岛弧的改进地震数据。结合重力和地震数据，可以更准确地了解海洋岛弧下的地下构造，并更好地估计岩浆过程中产生的地壳体积。本研究调查的大洋岛弧显示地壳厚度在20 ~ 30公里之间。利用这个厚度，估算出每个岛弧的相关地壳体积。将地壳体积除以弧开始俯冲的年龄，得到弧岩浆添加速率为30-95 km/ km/Myr。这里提出的估计几乎是以前估计的岩浆添加速率的两倍。(C) 2002 Elsevier Science B.V.版权所有
Numerous studies have been conducted in order to look into the evolution of the continental crust. Some suggest that one of the mechanisms which contribute to the growth of continental crust is arc magmatism. It is in this context that Reymer and Schubert (Tectonics 3 (1984) 63) estimated arc magmatic addition rates to the continental crust. Their results suggest that island arc magmatism was producing material at an average rate of 20-40 km(3)/km/Myr (volume per unit width along the strike direction of arc). The present work utilizes the most recent worldwide marine gravity data, together with improved seismic data from some oceanic island arcs in the western Pacific region. The combined gravity and seismic data allow a more accurate image of the subsurface configuration beneath the oceanic island arcs and yield better estimates of crustal volumes created during are magmatic processes. Oceanic island arcs investigated in this study show a crustal thickness ranging from 20 to 30 km. Utilizing this thickness, the relevant crustal volume for each island arc is then estimated. Dividing the crustal volume by the age of initiation of subduction of the arc gives arc magmatic addition rates of 30-95 km(3)/km/Myr. The estimates presented here are nearly twice as high as the previous estimates of are magmatic addition rates. (C) 2002 Elsevier Science B.V. All rights reserved.