Near surface halogen (F, Cl, Br, I) cycle

近表面卤素（F、Cl、Br、I）循环

• 批准号: 281601517
• 负责人: Professor Dr. Gregor Markl
• 金额: --
• 依托单位: Arbeitsgruppe Petrologie und Mineralische Rohstoffe
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2015
• 资助国家: 德国
• 起止时间: 2014-12-31 至 2020-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/281601517?language=en
• 关键词: Near; surface; halogen; Cl; Br

Halogens are omnipresent in nature; the heavier halogens (Cl, Br and I) are commonly regarded as inert tracers in fluid-involving processes in soils and upper crustal rocks. There is, however, increasing evidence that this may not be true and that the halogens record various fluid sources, reactions and precipitation processes in low-temperature environments. These processes are recorded by pyromorphite-group minerals (PyGM), which form by the supergene weathering of Pb ores (e. g., galena) incorporating halogens at the wt.% level. These minerals still form today during near-surface fluid-mediated processes and record the halogen characteristics (e.g., F/Cl, Br/Cl, I/C ratios) of near surface fluids that are involved in their formation at ambient conditions.During the first funding period of the project, the halogen incorporation into PyGM, the behavior of halogens (F, Cl, Br, I) in different depth layers of two soil profiles and in surface waters (precipitation, soil solutions, creek waters and adit waters) was investigated. Furthermore, since adsorption has a major influence on the near surface halogen cycle, we already started to investigate adsorption processes of halogens on different clay mineral fractions. To finish up this project we aim to characterize halogen partitioning between PyGM and fluids of different composition. It is therefore planned 1. to perform a series of experiments and to determine halogen concentrations in freshly precipitated PyGM crystals and in the corresponding fluid from which the crystals precipitated and 2. to finish the determination of halogen concentrations in separated clay fractions from the soil profiles. With this comprehensive data set we will be able to develop a detailed model for halogen distribution, mobilization and important retention processes close to the surface, with a possible application of PyGM as low-temperature fluid monitor.

卤素本质上是无处不在的。较重的卤素（CL，BR和I）通常被视为土壤和上层岩石中流体涉及流体过程中的惰性示踪剂。但是，越来越多的证据表明这可能不是事实，并且卤素记录了低温环境中各种流体源，反应和降水过程。这些过程是通过pyromorthite-group矿物（Pygm）记录的，这些过程由PB矿石的超基因风化（例如，Galena）在wt。％水平上掺入卤素。这些矿物在近表面流体介导的过程中仍形成，并记录近表面流体的卤素特征（例如F/Cl，Br/Cl，I/C比），这些表面流体在环境状态下与其形成有关的近表面流体。在项目的第一个资助期间。 （降水，土壤溶液，小溪水和ADIT水域）进行了研究。此外，由于吸附对近表面卤素周期有重大影响，因此我们已经开始研究卤素对不同粘土矿物馏分的吸附过程。为了完成该项目，我们旨在表征pygm和不同组成流体之间的卤素分配。因此，计划1。进行一系列实验并确定新鲜沉淀的pygm晶体中的卤素浓度以及在相应的液体中沉淀的晶体和2。完成从土壤剖面的分离的粘土馏分中测定卤素浓度。使用此综合数据集，我们将能够开发一个详细的模型，用于卤素分布，动员和靠近表面的重要保留过程，并可能将pygm作为低温流体监测器的应用。