Rates and mechanisms of element transfer during mineral reactions in the presence of a fluid phase

存在流体相的矿物反应过程中元素转移的速率和机制

基本信息

批准号：
208764835
负责人：
Professor Dr. Thomas Müller
金额：
--
依托单位：
Institut für Geologie, Mineralogie und Geophysik
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2012
资助国家：
德国
起止时间：
2011-12-31 至 2018-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/208764835?language=en
关键词：
Rates mechanisms element transfer during

项目摘要

The Earth is characterized by a high variance of element and isotope distribution with respect to space and time. The resulting dynamic system therefore requires substantial transport of heat and mass on very different scales (from single atoms to several hundreds of kilometers), which are typically driven by disequilibrium conditions. In crustal rocks most of the mass transport is related to mineral reactions. The proposed project quantitatively investigates processes occurring during mineral reactions in the carbonate system on a small scale. The new challenge of this proposal is the quantitative parameterization of non-equilibrium processes as its record of element and isotope zoning observed in natural samples contain information on the actual path, i.e. the operating mechanism and the time taken to get there. We hypothesize that the actual reaction mechanism depend on the deviation from the equilibrium state and that resulting zoning patterns can be resolved quantitatively. Hence, the proposed project aims to evaluate the dynamic evolution of mineral a composition in space and time along any P-T-X-t-path. Experiments will be carried out to systematically studying element and isotope exchange between co-existing mineral pairs. Experimental runs will be analyzed for surface processes and by compositional depth profiling. A numerical model will be developed to predict the reaction mechanism and the spatial composition of elements and isotopes during mineral reactions occurring along any given P-T-X-t-path. Modeling results will be tested against natural observations in regional carbonate bearing metamorphic rocks exhibiting reaction rims of ankerite surrounding cores of dolomite composition. The resulting knowledge provide the information on timescales necessary to equilibrate commonly used thermo(baro)meters which are inherently linked to all geochronology methods by the concept of diffusive closure. The gained knowledge can be used to extrapolate and estimate the rates of element and isotope transport through the crust and thus quantify their cycles in the Earth system.

地球的特征是相对于空间和时间的元素和同位素分布的差异。因此，所得的动态系统需要在非常不同的尺度（从单个原子到数百公里）上大量的热量和质量运输，这通常是由不平衡条件驱动的。在地壳岩石中，大多数质量运输都与矿物反应有关。拟议的项目对碳酸盐系统中矿物反应期间发生的过程进行了定量研究。该提案的新挑战是对非平衡过程的定量参数化，因为其在天然样本中观察到的元素和同位素分区的记录包含有关实际路径的信息，即操作机制和到达那里所花费的时间。我们假设实际的反应机理取决于与平衡状态的偏差，并且可以定量解析所得的分区模式。因此，拟议的项目旨在评估沿任何P-T-T-T-T-PATH上的空间和时间组成的动态演化。实验将进行系统地研究共存矿物对之间的元素和同位素交换。实验运行将分析表面过程和组成深度分析。将开发一个数值模型，以预测沿任何给定的P-T-T-T-T-Path发生的矿物反应期间元素和同位素的空间组成。建模结果将在具有变质岩石的区域碳酸盐岩中的自然观察结果进行测试，这些岩石岩石岩石岩石的反应边缘周围是白云石组成的核心的反应边缘。所得的知识提供了有关平衡常用的热（巴罗）仪表所需的时间尺度的信息，这些信息通过扩散闭合的概念固有地链接到所有地球人类学方法。获得的知识可用于推断和估计通过地壳传输的元素和同位素传输的速率，从而量化其在地球系统中的循环。