Magmatic and Amagmatic Contributions to Crustal Growth of an Island-Arc System: The Philippine Example
Magmatic and Amagmatic Contributions to Crustal Growth of an Island-Arc System: The Philippine Example
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DOI：
10.2747/0020-6814.45.10.922
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发表时间：
2003-10
影响因子：
2.6
通讯作者：
C. Dimalanta;G. Yumul
中科院分区：
文献类型：
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作者：
C. Dimalanta;G. Yumul
陆壳的生长包括岩浆作用和无岩浆作用两方面的贡献。在菲律宾，存在着许多活火山和潜在活火山以及蛇绿岩/蛇绿岩杂岩，证明了弧岩浆作用和大洋岩石圈侵位对地壳生长的重要作用。然而，由于缺乏地球物理数据（例如，地震折射数据、地震速度模型等）。本研究根据现有的地球物理和地球化学数据，提出了地壳厚度值的综合。这些厚度被用来确定由弧岩浆活动以及蛇绿岩的岩浆侵位所导致的地壳生长所产生的物质的体积。根据计算，弧岩浆活动，而不是蛇绿岩侵位，在菲律宾的地壳生长作出了更显着的贡献。弧岩浆活动的增长率为25 - 67 km 3/km/m.y.与西太平洋其他岛弧系统中计算的弧岩浆添加率相当。蛇绿岩的吸积速率从2至19 km 3/km/m.y.不等。
The growth of continental crust consists of contributions from both magmatic and amagmatic processes. In the Philippines, the presence of numerous active and potentially active volcanoes and ophiolite/ophiolitic complexes attests to the significant role of arc magmatism and oceanic lithosphere emplacement to crustal growth. However, an estimate of the magmatic and amagmatic contributions to crustal growth has never been attempted previously for this particular island-arc system due to the paucity of geophysical data (e.g., seismic refraction data, seismic velocity models, etc.). This study presents a synthesis of crustal thickness values based on available geophysical and geochemical data. These thicknesses are used to determine the volume of material produced by arc magmatism as well as crustal growth resulting from the amagmatic emplacement of ophiolites. Based on the computations, arc magmatism, rather than ophiolite emplacement, has contributed more significantly to crustal growth in the Philippines. Arc magmatism growth rates of 25 to 67 km3/km/m.y. are comparable to those of computed arc magmatic addition rates in other island-arc systems in the Western Pacific. Ophiolite accretion rates vary from 2 to 19 km3/km/m.y.