The behavior of high field-strength elements (HFSE) in F-rich peralkaline systems

高场强元素 (HFSE) 在富氟过碱性体系中的行为

• 批准号: 526130846
• 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
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/526130846?language=en
• 关键词: behavior; field; strength; elements; HFSE

Peralkaline igneous rocks (rocks with a molar (Na+K)/Al ratio > 1) are strongly enriched in halogens, rare earth elements (REE), and high field strength elements (HFSE; Zr, Hf, Nb, Ta) and represent some of the most promising sources for future HFSE and REE supply. This project investigates the behaviour of halogens and HFSE/REE-bearing phases in the texturally and compositionally zoned peralkaline plutonic Monchique complex (Portugal) that evolved from gabbroic to foid syenitic compositions. The special role of sodalite, fluorite and various F-rich Na-Ca-HFSE disilicates (FDC) for the retention of halogens in peralkaline magmas will be investigated and the variable effects of fractional crystallization, fluid exsolution/degassing and fluid-wall rock interaction on halogen systematics and HFSE/REE mobility will be distinguished from each other. The following three working hypotheses will be guiding the workflow of the anticipated project: 1) Halogen abundances and halogen systematics (F/Cl, Cl/Br ratios) in the Monchique rocks reflect the effects of fractional crystallization during magmatic stages and redistribution of halogens caused by fluid exsolution and accompanied (autometasomatic) hydrothermal alteration. 2) The Monchique complex shows vertical and horizontal zonation with respect to the relative abundance of sodalite-FDS assemblages, which may or may not correlate with the HFSE distribution in this tabular body. 3) Locally developed fenites around the Monchique complex are Cl-rich but F-poor and therefore devoid of FDS but zircon- and titanite-bearing, which is mainly controlled by the low F/Cl ratio of the fenitizing fluids. To test these hypotheses, we will combine detailed petrography, whole-rock analysis (XRF, ICP-MC, CIC), mineral chemistry (EPMA, CIC, LA-ICP-MS), thermodynamic modelling, and fluid inclusion investigations (microthermometry, LA-ICP-MS). The expected results of this project will not only decipher halogen and HFSE behavior in such a peralkaline system, but will certainly have general implications on the formation and migration of halogen-bearing fluids that are capable of HFSE transport within a shallow-level plutonic complex. Geochemical monitors (e.g., whole rock halogen data, HFSE data) will be combined with mineralogical observations (e.g., FDS, sodalite, fluorite distribution) and will allow for a detailed view on fluid exsolution/degassing processes in tabular magma bodies.

甲基盐火成岩岩石（具有摩尔（Na+K）/Al比率> 1）的岩石（岩石）在卤素，稀土元素（REE）和高场强元素（HFSE； ZR，HF，NB，NB，TA）中非常丰富，并代表了未来HFSE和REE供应的一些最有希望的来源。该项目研究了卤素和HFSE/REE阶段在质地和成分划分的paralline Plutonic Monchique复合物（葡萄牙）中的行为，这些复合物（葡萄牙）从Gabbroic演变为foid syenitic组成。将研究Sodalite，Sodalite，氟化石和各种FICH NA-CA-HFSE（FDC）保留卤素在多烷烃岩浆中的保留，并且将研究对卤代结晶，流体结晶，流体结晶，流体脱位/脱气和流体岩石相互作用的可变影响，对卤素系统和HFSE系统的移动性将与其他相差与其他相差。以下三个工作假设将指导预期项目的工作流程：1）Monchique Rocks中的卤素丰度和卤素系统（F/CL，Cl/BR比）反映了岩浆阶段分数结晶的影响，以及由流动性和伴奏（自动化的）引起的Halogens中的卤素重新分布。 2）相对于Sodalite-FDS组合的相对丰度，Monchique复合物显示出垂直和水平分区，这可能与该表格体中的HFSE分布相关，也可能不会相关。 3）周围元素复合物周围的局部开发的fenite富含Cl，但F-poor，因此没有FD，但含有锆石和钛铁矿的含量，主要由Fenitization Flys的低F/Cl比控制。为了检验这些假设，我们将结合详细的岩石学，全岩分析（XRF，ICP-MC，CIC），矿物质化学（EPMA，CIC，LA-ICP-MS），热力学建模和流体融合研究（Microtheremotie groumption（Microthermopery，LA-ICP-MS））。该项目的预期结果不仅将在这种日期系统中解密卤素和HFSE行为，而且肯定会对能够在浅层层状型植物复合物中进行HFSE转运的含卤素液的形成和迁移具有一般影响。地球化学监测器（例如，全岩卤素数据，HFSE数据）将与矿物学观测值（例如FDS，Sodalite，氟）分布相结合，并将允许对表格岩浆物体中的流体Exsolid Exsolid/Dewassing过程进行详细的视野。