Transport, Concentration, and Deposition of Precious Metals in Layered Gabbros During Continental Rifting

大陆裂谷期间层状辉长岩中贵金属的传输、富集和沉积

• 批准号: 9206962
• 负责人: Dennis Bird
• 金额: $ 4.81万
• 依托单位: Stanford University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1992
• 资助国家: 美国
• 起止时间: 1992-07-01 至 1993-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9206962&HistoricalAwards=false
• 关键词: Transport; Concentration; Deposition; Precious; Metals

Recent discoveries of gold and platinum group (PGE) mineralization in Eocene layered gabbros of East Greenland demonstrate that physical and chemical processes associated with the transition from continental to oceanic rifting can concentrate precious metals in the Earth's crust. One of these gabbros, the Kap Edvard Holm Complex, exhibits an unusual combination of features related to stratiform precious metal mineralization. An understanding of these processes requires detailed field, petrologic, isotopic, and chemical analyses, combined with theoretical analysis of the thermodynamic and transport characteristics of magma-hydrothermal systems. The long-term plans for this research program inviove using these techniques to provide new insights into the nature of processes controlling: 1) precious metal concentration during gabbro crystallization; and 2) precious metal transport and deposition in gabbro-hosted hydrothermal systems. A specific objective of the research will be evaluation of various hypotheses that may explain the unusually high ratio of precious metal to sulfide that is characteristic of this deposit. Investigation of the processes responsible for mineralization in the East Greenland gabbros is potentially of great importance to understanding the global distribution of precious metals and to formulating future mineral exploration strategies. The present award will enable him to get started while he is formulating a plan to achieve the long-term goals.

最近在东格陵兰岛始新世层状辉长岩中发现的金和铂族(PGE)矿化表明，与大陆裂谷向海洋裂谷过渡有关的物理和化学过程可以在地壳中浓缩贵金属。其中一个辉长岩，Kap Edvard Holm杂岩，表现出与层状贵金属矿化有关的不寻常的组合特征。对这些过程的理解需要详细的野外、岩石学、同位素和化学分析，并结合对岩浆-热液系统的热力学和运移特征的理论分析。这项研究计划的长期计划是使用这些技术为控制过程的本质提供新的见解：1)辉长岩结晶过程中贵金属的浓缩；以及2)贵金属在辉长岩中的迁移和沉积。这项研究的一个具体目标将是评估各种假设，这些假设可能解释该矿床特有的贵金属与硫化物的异常高比率。调查东格陵兰辉长岩的成矿过程对于了解贵金属的全球分布和制定未来的矿产勘探战略具有重要意义。目前的奖项将使他能够在制定实现长期目标的计划时开始工作。