Non‐hotspot volcano chains originating from small‐scale sublithospheric convection
Non‐hotspot volcano chains originating from small‐scale sublithospheric convection
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DOI：
10.1029/2007gl031636
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发表时间：
2007-12
影响因子：
5.2
通讯作者：
M. Ballmer;J. Hunen;Garrett Ito;P. Tackley;T. Bianco
中科院分区：
文献类型：
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作者：
M. Ballmer;J. Hunen;Garrett Ito;P. Tackley;T. Bianco
一些海洋火山链违背了地理年龄递进的热点假说的预测。用来解释这些观测结果的一种机制是小尺度岩石圈下对流（SSC）。在这项研究中，我们在热化学、三维数值模型中探索了这一概念。由SSC引起的融化显示出与板块运动平行的细长特征（约750公里），而不仅仅是在一个固定点；因此，火山活动是链状的，而不是像热点一样的线性年龄递进。火山活动首次发生的海底年龄对地幔温度很敏感，因为较高的温度增加了SSC的开始年龄，因为先前海中脊融化的较厚残留物起到了稳定作用。地幔黏度控制着熔体产生的速率，黏度降低导致对流和火山活动更加剧烈。计算预测了普卡普卡山脊的许多关键观测结果，以及与Line， Cook‐Austral和马绍尔群岛相关的火山群。
Some oceanic volcano chains violate the predictions of the hotspot hypothesis for geographic age progressions. One mechanism invoked to explain these observations is small‐scale sublithospheric convection (SSC). In this study, we explore this concept in thermo‐chemical, 3D‐numerical models. Melting due to SSC is shown to emerge in elongated features (∼750 km) parallel to plate motion and not just at a fixed spot; therefore volcanism occurs in chains but not with hotspot‐like linear age progressions. The seafloor age at which volcanism first occurs is sensitive to mantle temperature, as higher temperatures increase the onset age of SSC because of the stabilizing influence of thicker residue from previous mid‐ocean ridge melting. Mantle viscosity controls the rate of melt production with decreasing viscosities leading to more vigorous convection and volcanism. Calculations predict many of the key observations of the Pukapuka ridges, and the volcano groups associated with the Line, Cook‐Austral, and Marshall Islands.