The fate of arsenic in low to medium temperature hydrothermal systems

砷在中低温热液系统中的命运

• 批准号: 391757545
• 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: 2018
• 资助国家: 德国
• 起止时间: 2017-12-31 至 2021-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/391757545?language=en
• 关键词: fate; arsenic; low; medium; temperature

Arsenic is a toxic element present in most shallow fluid systems, and sometimes in very high concentrations which pose a considerable health risk. The shallow geological and geochemical processes involving arsenic are relatively well investigated and will not be the topic of the present proposal. However, they are typically related to pre-enrichment of arsenic in higher temperature, hydrothermal systems from which the element arsenic is precipitated in various oxidation states such as native arsenic, arsenides, sulfarsenides and sulfides (and, rarely, as arsenites or arsenates). At temperatures below about 250°C, native arsenic, realgar, orpiment and Co-Ni-Fe arsenides play an important role. Their assemblages, their conditions of formation, their thermodynamic phase relations, the composition of the solutions they crystallize from and the geological/geochemical processes responsible for their precipitation (cooling, fluid mixing, fluid-rock interaction) will be investigated in this project in a well known region (Schwarzwald, SW Germany) involving a perfect, large sample set from different stratigraphic levels (and, hence formed at various temperatures) in order to understand a higher temperature part of the arsenic cycle and its connection to the low-temperature, shallow proccesses. This work will involve mineral chemical, fluid inclusion and paragenetic analyses as well as thermodynamic calculations.

砷是一种有毒元素，存在于大多数浅层流体系统中，有时浓度非常高，对健康构成相当大的风险。涉及砷的浅层地质和地球化学过程的研究相对较好，将不是本提案的主题。然而，它们通常与砷在高温热液系统中的预富集有关，砷元素从热液系统中以各种氧化态析出，如天然砷、砷化物、磺胺类和硫化物（很少以亚砷酸盐或砷酸盐的形式析出）。在250°C以下的温度下，天然砷、雄黄、铬和钴镍铁砷化物起重要作用。它们的组合、它们的形成条件、它们的热力学相关系、它们结晶的溶液的组成以及导致它们沉淀的地质/地球化学过程（冷却、流体混合、流体-岩石相互作用）将在这个项目中在一个著名的地区（德国西南部的施瓦兹瓦尔德）进行研究，涉及来自不同地层水平(和；因此在不同的温度下形成)，以便了解砷循环的较高温度部分及其与低温浅层过程的联系。这项工作将涉及矿物化学、流体包裹体和共生分析以及热力学计算。