Global thermal models of the lithosphere
Global thermal models of the lithosphere
复制标题
岩石圈的全球热模型
DOI：
10.1093/gji/ggx144
复制
发表时间：
2017
影响因子：
2.8
通讯作者：
M. Guerri
中科院分区：
文献类型：
--
作者：
F. Cammarano;M. Guerri
揭开地球最外层外壳的热结构是理解其演化的关键。我们通过对全球剪切速度(VS)模型的解释来获得温度。地震模型很好地确定了长波长热结构，只受成分效应和矿物物理性质的不确定性的影响很小。然而，绝对温度和深度梯度并没有得到很好的约束。加上岩石学、热流观测和大洋岩石圈热演化的约束条件，有助于更好地估计岩石圈顶部的绝对温度。我们制作了不同空间分辨率的岩石圈全球热模型，最高可达24次球谐，并提供了估计的标准偏差。除导热系数外，所有相关的物理性质都是基于自洽的热力学模型方法。我们的全球热模型还包括密度和纵波速度(Vp)，它们要么假设成分没有横向变化，要么假设简单的参考三维组成结构，其中考虑了化学亏损的大陆岩石圈。全球热模型应作为在较小空间尺度上移动的基础，其中可包括地球物理观测所需的其他热化学变化。
Unravelling the thermal structure of the outermost shell of our planet is key for understanding its evolution. We obtain temperatures from interpretation of global shear-velocity (VS) models. Long-wavelength thermal structure is well determined by seismic models and only slightly affected by compositional effects and uncertainties in mineral-physics properties. Absolute temperatures and gradients with depth, however, are not well constrained. Adding constraints from petrology, heat-flow observations and thermal evolution of oceanic lithosphere helps to better estimate absolute temperatures in the top part of the lithosphere. We produce global thermal models of the lithosphere at different spatial resolution, up to spherical-harmonics degree 24, and provide estimated standard deviations. All relevant physical properties, with the exception of thermal conductivity, are based on a self-consistent thermodynamical modelling approach. Our global thermal models also include density and compressional-wave velocities (VP) as obtained either assuming no lateral variations in composition or a simple reference 3-D compositional structure, which takes into account a chemically depleted continental lithosphere. The global thermal models should serve as the basis to move at a smaller spatial scale, where additional thermo-chemical variations required by geophysical observations can be included.