Laboratory investigations and theoretical considerations on the electrical properties of seafloor massive sulfides

海底块状硫化物电特性的实验室研究和理论思考

• 批准号: 326799290
• 负责人: Professor Dr. Andreas Hördt
• 金额: --
• 依托单位: Institut für Geophysik und Extraterrestrische Physik
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2016
• 资助国家: 德国
• 起止时间: 2015-12-31 至 2021-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/326799290?language=en
• 关键词: Laboratory; investigations; theoretical; considerations; electrical

In order to satisfy future global demands for metals, there is an increasing interest in deep-sea mining. Seafloor massive sulfides (SMS) are considered an important marine metal resource. They are generated in regions of submarine volcanic activity, in particular mid-ocean ridges. Since underwater mining is difficult and expensive, a careful exploration and characterisation of seafloor deposits is essential. Electrical methods, and in particular induced polarization, are considered to play a key role, because they determine the electrical conductivity of the rocks, which depends on mineral content. Unlike for continental ores, where a wealth of data exists, the electrical properties of SMS are poorly known. Seafloor samples are rare and difficult to obtain, and only a small number of studies exists. Results obtained for continental sulfides cannot easily be transferred to seafloor conditions, because the marine fluids are considerably more saline, and the rock chemistry and texture may differ. In this project, we measure the frequency-dependent electrical properties of a large number of SMS samples from several worldwide locations, including deposits in the Atlantic, Pacific and Mediterranean. The results will be analysed in the context of mineralogical data, in order to identify potential relationships between electrical parameters and mineral content, that will constitute a basis for future exploration programs. The measurements will be preceded by methodological studies to define the optimum procedure to measure electrical properties of samples of irregular shapes. The SMS samples are valuable and it is generally not desired to destroy them, such that standard methods using cylindrical plugs cannot be applied to all samples. The data interpretation will be supported by extensive theoretical considerations, in order to obtain a fundamental understanding of the physical processes that control the electrical impedance of mineralized rock. Existing theories exclusively assume that the minerals are disseminated, whereas experimental evidence suggests that connected veins have a huge influence on electrical conductivity and cannot be neglected. Our theoretical advancements will combine existing models of the electrochemistry with new methods recently developed for unmineralized sediments.

为了满足未来对金属的需求，对深海采矿的兴趣越来越大。海底巨大硫化物（SMS）被认为是重要的船用金属资源。它们是在海底火山活动的地区，尤其是海洋中部山脊产生的。由于水下开采是困难且昂贵的，因此必须仔细探索和对海底沉积物的特征。电气方法，特别是诱导的极化被认为起着关键作用，因为它们决定了岩石的电导率，这取决于矿物质含量。与存在大量数据的大陆矿石不同，SM的电气性能是鲜为人知的。海底样品罕见且难以获得，只有少量研究存在。大陆硫化物获得的结果无法轻易转移到海底条件上，因为海洋液的盐水要多得多，而且岩石化学和质地可能有所不同。在这个项目中，我们测量了来自多个世界地点的大量SMS样本的频率依赖性电性能，包括大西洋，太平洋和地中海的沉积物。为了确定电参数和矿物质含量之间的潜在关系，将在矿物学数据的背景下进行分析，这将构成将来探索计划的基础。测量结果将在方法论研究之前，以定义测量不规则形状样品的电性能的最佳程序。 SMS样品很有价值，通常不希望破坏它们，因此使用圆柱插头的标准方法不能应用于所有样品。 为了获得对控制矿化岩石电阻抗的物理过程的基本理解，将通过广泛的理论考虑来支持数据解释。现有的理论仅假定矿物是传播的，而实验证据表明，连接的静脉对电导率有很大影响，不能忽略。我们的理论进步将将现有的电化学模型与最近针对无矿化沉积物开发的新方法相结合。