Chlorine isotope fractionation in alkaline magmatic systems

碱性岩浆系统中的氯同位素分馏

• 批准号: 450099520
• 负责人: Privatdozent Dr. Michael Marks
• 金额: --
• 依托单位: Arbeitsgruppe Geologie und Geodynamik
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2020
• 资助国家: 德国
• 起止时间: 2019-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/450099520?language=en
• 关键词: Chlorine; isotope; fractionation; alkaline; magmatic

This project represents a systematic study to constrain the behaviour of the Cl isotope system in alkaline magmatic to hydrothermal systems and the Cl isotope heterogeneity in the mantle. Because of their general derivation from lithospheric mantle sources and their halogen-rich nature, alkaline rocks are important to understand halogen transport from the mantle into the crust and halogen budgets during emplacement, differentiation, and fluid exsolution/degassing of magmatic systems. The extensive sample collection to be worked with includes plutonic, volcanic and metamorphosed alkaline rocks from more than 40 localities worldwide.Based on our preliminary data, the following three hypotheses will be tested during this project: (i) Magmatic processes, such as fractional crystallization and fluid exsolution/ degassing cause fractionation of stable Cl isotopes (ii) Heterogeneity of the mantle with respect to Cl isotope compositions is recorded in alkaline magmas (iii) Deformation and fluid-rock interaction during metamorphism of alkaline rocks does not significantly change their Cl isotopic composition. The project will use Cl isotope data (ICP-MS, SIMS), halogen (F, Cl, Br, I) and S concentration data (EPMA, CIC) as well as O and S isotope data on mineral separates. Combined with mass balance and Rayleigh-type calculations, this will allow to (i) develop applications of Cl isotope data for deciphering magmatic to hydrothermal processes and (ii) to constrain global compositional heterogeneities in the (lithospheric) mantle with respect to halogen ratios (e.g., F/Cl, Cl/Br, Cl/I) and Cl isotope compositions, for which already evidence was presented.

该项目代表了一项系统的研究，旨在限制碱性岩浆中CL同位素系统的行为，并在地幔中对水热系统和CL同位素异质性。由于它们从岩石圈地幔源及其富含卤素的性质的一般推导，因此碱性岩石对于了解从地幔转移到地壳和卤素预算的过程中，在增强，分化和流体的磁磁系统中的卤素预算非常重要。 The extensive sample collection to be worked with includes plutonic, volcanic and metamorphosed alkaline rocks from more than 40 localities worldwide.Based on our preliminary data, the following three hypotheses will be tested during this project: (i) Magmatic processes, such as fractional crystallization and fluid exsolution/ degassing cause fractionation of stable Cl isotopes (ii) Heterogeneity of the mantle with respect在碱性岩石变质过程中，在碱性岩浆（III）变形和流体岩石相互作用中记录了CL同位素组成，并未显着改变其CL同位素组成。该项目将使用CL同位素数据（ICP-MS，SIMS），卤素（F，CL，BR，I）和S浓度数据（EPMA，CIC）以及矿物分离的O和S同位素数据。结合质量平衡和瑞利类型的计算，这将允许（i）开发Cl同位素数据的应用，以将岩浆解释到水热过程中，以及（ii）在（岩石圈）的阴影中限制全球组成的异质性，以halogen的比率（例如，f/cl/cl/cl/br，cl/cl，cl，cl is cl，cl/cl is coptipe，cl/cl/cl is copties copties at cl。