Crustal Architecture of the Cascadia Forearc
Crustal Architecture of the Cascadia Forearc
复制标题
卡斯卡迪亚前弧的地壳结构
DOI：
10.1126/science.266.5183.237
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发表时间：
1994
期刊：
影响因子：
56.9
通讯作者：
Y. Nakamura
中科院分区：
文献类型：
--
作者：
A. Tréhu;Isa Asudeh;T. Brocher;J. Luetgert;W. Mooney;J. Nábělek;Y. Nakamura
地震剖面数据表明，古新世和始新世早期的一个增生的海洋碎屑层的厚度沿卡斯卡迪亚俯冲带的走向变化约为沿着4倍，该碎屑层形成了俄勒冈州西部和华盛顿下方大部分前弧的基底。在俄勒冈州海岸山脉之下，增生的火山岩厚度为25至35公里，而在温哥华岛近海，火山岩厚度约为6公里。这些变化与弧岩浆活动，弧前地震活动，长期弧前变形的变化。有人建议，弧前地壳的强度增加的厚度增加的加积岩和几何形状的向海边缘的这个加积岩的影响内的俯冲复合体的变形和控制量的沉积物是深深俯冲。
Seismic profiling data indicate that the thickness of an accreted oceanic terrane of Paleocene and early Eocene age, which forms the basement of much of the forearc beneath western Oregon and Washington, varies by approximately a factor of 4 along the strike of the Cascadia subduction zone. Beneath the Oregon Coast Range, the accreted terrane is 25 to 35 kilometers thick, whereas offshore Vancouver Island it is about 6 kilometers thick. These variations are correlated with variations in arc magmatism, forearc seismicity, and long-term forearc deformation. It is suggested that the strength of the forearc crust increases as the thickness of the accreted terrane increases and that the geometry of the seaward edge of this terrane influences deformation within the subduction complex and controls the amount of sediment that is deeply subducted.