The persistent mantle plume myth
The persistent mantle plume myth
复制标题
持续存在的地幔柱谬论
DOI：
10.1080/08120099.2013.835283
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发表时间：
2013-10
影响因子：
1.2
通讯作者：
Don L. Anderson
中科院分区：
文献类型：
--
作者：
Don L. Anderson
地震学、热力学和经典物理学--与傅立叶、德拜、伯恩、格吕内森、开尔文、瑞利、卢瑟福、兰伯格和白桦树等名字相关的物理学--表明，大型长寿命板块下的环境浅地幔比为全球扩张脊系提供燃料的被动上升中的浅地幔高数百度，地幔约200公里以下的位温通常随着深度的下降而下降，深部地幔的低剪切波速特征是宽的、迟缓的和穹顶的，而不是狭窄的地幔热柱。与通常被认为是板内火山源头的地区相比，地幔的表面边界层更大，也可能更热。这意味着对夏威夷和火成岩大省的“地幔热柱”解释是不必要的。在孤立的系统中，从内部加热，从上方冷却，上升流是被动的和大的，这表明层析特征和上升流是对板块构造、扩张和俯冲的反应，至少在融化在浅层引入小的本征浮力之前是这样。熔融异常，或称“热点”，是板块构造的副作用，主要由边界层中的剪切驱动过程提供，而不是深浮力上升。致密的基底混杂岩(BAM)组分进一步稳定了地幔的下边界层。大洋中脊和与之相关的广泛的被动亏损地幔(DM)隆起可能起源于过渡区。更深的地幔隆起是留在下地幔的宽阔的穹顶。
Seismology, thermodynamics and classical physics—the physics associated with the names of Fourier, Debye, Born, Grüneisen, Kelvin, Rayleigh, Rutherford, Ramberg and Birch—show that ambient shallow mantle under large long-lived plates is hundreds of degrees hotter than in the passive upwellings that fuel the global spreading ridge system, that potential temperatures in mantle below about 200 km generally decrease with depth and that deep mantle low shear wave-speed features are broad, sluggish and dome-like rather than narrow and mantle-plume-like. The surface boundary layer of the mantle is more voluminous and potentially hotter than regions usually considered as sources for intraplate volcanoes. This means that the ‘mantle plume’ explanation for Hawaii and large igneous provinces is unnecessary. In isolated systems, heated from within and cooled from above, upwellings are passive and large, which suggests that tomographic features, and upwellings, are responses to plate tectonics, spreading and subduction, at least until melting introduces a small intrinsic buoyancy at shallow depths. Melting anomalies, or ‘hotspots,’ are side-effects of plate tectonics and are fed primarily by shear-driven processes in the boundary layer (BL), not by deep buoyant upwellings. A dense basal melange (BAM) component further stabilises the lower boundary layer of the mantle. Mid-ocean ridges and associated broad passive depleted mantle (DM) upwellings probably originate in the transition region. Deeper mantle upwellings are broad domes that stay in the lower mantle.