Geodynamic models with thermodynamically self-consistent mineral physics

具有热力学自洽矿物物理的地球动力学模型

• 批准号: 41509765
• 负责人: Professor Dr. Hans-Peter Bunge, Ph.D.
• 金额: --
• 依托单位: Bayerisches Forschungsinstitut für Experimentelle Geochemie und Geophysik (BGI)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2007
• 资助国家: 德国
• 起止时间: 2006-12-31 至 2008-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/41509765?language=en
• 关键词: Geodynamic; models; thermodynamically; self; consistent

We propose to combine geodynamic mantle modeling with thermodynamic models of mantle mineralogy in order to gain a better understanding of the thermal and elastic structure of Earth s mantle. For the geodynamic modeling we will use two dimensional (2-D) and three dimensional (3-D) mantle convection codes. For the thermodynamic mantle model we will apply the Gibbs-free-energy minimization method in order to compute mantle phase equilibria for a range of chemical mantle models. (1) temperature fields from mantle convection modeling will be postprocessed: we will assign to each Temperature (T) and Pressure (P) grid point value from the convection calculation its corresponding equilibrium mineral assemblage and physical properties. (2) We will then couple the convection and mineralogical model: we will use the density of the mineral assemblage to compute buoyancy forces (via the buoyancy term in the momentum equation) in the convection model. Thus densities derived from the mineralogical model establish convective flow and a thermal structure in the geodynamic model, while at the same time the P, T structure of the convection model is used in the computation of the equilibrium mineral assemblage. By combining the equation-of-state parameters with a shear wave model we will be able to study convection consistently with the underlying mineralogy. The proposed work will permit us to compare predictions of geodynamic mantle models directly to observed seismic properties. This is important because recent seismic studies of the mantle show results that are not easily understood in terms whole mantle convection. We will test the hypothesis that the seismic results can be attributed in part to complexities in the mineralogy. The mineralogical model will be made available for general use through a website, as a research and teaching tool for the geophysical and high pressure mineralogical community.

为了更好地了解S地幔的热结构和弹性结构，我们提出将地球动力学地幔模拟与地幔矿物学热力学模型相结合。对于地球动力学模拟，我们将使用二维(2-D)和三维(3-D)地幔对流程序。对于热力学地幔模型，我们将应用Gibbs自由能最小化方法来计算一系列化学地幔模型的地幔相平衡。(1)对地幔对流模拟得到的温度场进行后处理：将对流计算得到的每个温度(T)和压力(P)网格点赋值为其相应的平衡矿物组合和物性。(2)然后我们将耦合对流和矿物学模型：我们将使用矿物组合的密度来计算对流模型中的浮力(通过动量方程中的浮力项)。因此，由矿物学模型得到的密度在地球动力学模型中建立了对流流动和热结构，同时对流模型的P、T结构被用于平衡矿物组合的计算。通过将状态方程参数与剪切波模型相结合，我们将能够研究与基础矿物学一致的对流。这项拟议的工作将使我们能够直接将地球动力学地幔模型的预测与观测到的地震属性进行比较。这一点很重要，因为最近对地幔的地震研究表明，从整个地幔对流的角度来看，结果并不容易理解。我们将检验这样一种假设，即地震结果可以部分归因于矿物学的复杂性。矿物学模型将通过一个网站供一般使用，作为地球物理和高压矿物学界的研究和教学工具。