Modelling of CHROMium Enrichment in the mantle and the crust

铬项目的主要目标是开发热力学上一致的多相流模型，以解释蛇绿岩单元中豆荚状铬铁矿矿床的形成。蛇绿岩由岩石组成，在其形成过程中显示出熔融/结晶过程的证据。由于铬是一种高度相容的元素，预计它在熔化过程中会留在残渣中。然而，我们的初步实验结果表明，随着H2O含量的增加，铬尖晶石变得不稳定，并与其他硅酸盐矿物(主要是辉石)一起熔融。这种对铬尖晶石的消耗导致熔体中铬含量的急剧增加。然而，尽管有这种富集过程，但这种铬浓度不足以形成铬铁矿沉积物。因此，我们得出结论，这些熔体的额外动员和富铬是必要的。为了模拟熔体的迁移过程，必须考虑来自地幔的富含H2O、饱和铬的岩浆中反应性多相流动的动力学。通过模拟铬富集的不同端元(如对流或反应输运)，我们将能够确认/拒绝甚至改进一些关于豆荚状铬矿床形成的现有假说。我们计划对含铬矿石的橄榄岩进行相平衡实验。这些实验将使我们能够得出进一步发展反应输运模型所需的结论。我们计划应用多相反应流模型来深入了解与成矿相关的过程。这些模型将与熔体与地幔岩石重新平衡的实验并行运行。我们的组合建模/实验方法将提供对建议的建模方法的彻底审查。我们的目标是使用反应性多相流模型来模拟成矿过程(从源头到矿床)。在此过程中，我们提出的模型将考虑来自天然豆荚状铬铁矿矿床的岩石学和现场证据。

The main objective of the CHROME project is to develop thermodynamically consistent multiphase flow models that can explain the formation of podiform chromite deposits in ophiolite units. Ophiolites consist of rocks that show evidence of melting/crystallization processes during their formation. Since chromium is a highly compatible element, it is expected to remain in the residuum during melting. However, our preliminary experimental results show that Cr spinel becomes unstable with increasing H2O content and melts together with the other silicate minerals (mainly pyroxenes). This consumption of Cr spinel leads to a dramatic increase in the Cr content of the melt. However, despite this enrichment process, this Cr concentration is not sufficient to form chromite deposits. Thus, we conclude that additional mobilization and Cr enrichment of these melts is necessary. To model the processes of melt transport, the dynamics of reactive multiphase flows in H2O-rich, Cr-saturated magmas from the Earth's mantle must be considered. By modeling the various end-members of Cr enrichment (e.g., convection or reactive transport), we will be able to confirm/reject or even refine some of the available hypotheses for the formation of podiform Cr deposits. We plan to conduct phase equilibrium experiments on the peridotitic rocks containing the Cr ores. These experiments will allow us to draw conclusions needed for further development of reactive transport models. We plan to apply multiphase reactive flow models to gain insight into the processes associated with ore formation. These models will be run in parallel with experiments in which melts are re-equilibrated with mantle rocks. Our combined modeling/experimental approach will provide a thorough review of the proposed modeling approaches. Our goal is to use reactive multiphase flow models to model ore formation processes (from source to deposit). In doing so, our proposed model will consider petrologic and field evidence from natural podiform chromite deposits.