Organic Geochemistry of Alligator Ridge Sediment-Hosted Gold Deposit

鳄鱼岭沉积金矿床的有机地球化学

• 批准号: 8707353
• 负责人: Philip Meyers
• 金额: $ 4.75万
• 依托单位: Regents of the University of Michigan - Ann Arbor
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1987
• 资助国家: 美国
• 起止时间: 1987-09-01 至 1989-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=8707353&HistoricalAwards=false
• 关键词: Organic; Geochemistry; Alligator; Ridge; Sediment

The role of organic matter in processes of ore deposition has been the subject of many recent meetings and symposia. For most deposits it is still unknown whether organic matter plays an active or passive part in determining the site and mechanism of precipitation of ore minerals. The proposed research is designed to determine the influence of organic matter on the geochemical evolution of the sediment-hosted gold deposit at Alligator Ridge is the only large deposit of this type but Alligator Ridge is the only large deposit where heating has not obliterated the original organic record. Preliminary analyses using "Rock-Eval" and aliphatic hydrocarbon extracts demonstrate that organic matter was not inert but was oxidized by mineralizing solutions. Numerous oxidation reactions are possible (to CO2, ether, carbonyl, or other groups), however, and preliminary thermo- dynamic calculations show that they occur over a wide range of oxidation-reduction conditions. It is proposed to determine the nature of oxidation and mineralizing reactions by (1) extract and Infrared analyses of kerogen to identify oxidized compounds; and (2) thermodynamic calculations to compare the redox state of organic matter to that of ore and alteration mineralization. Successful completion of the proposed research will lead to deeper insight into the influence of organic matter on the site and mechanism of gold deposition and may lead to more cost- effective schemes for discovering new deposits.

有机质在矿石沉积过程中的作用一直是最近许多会议和研讨会的主题。 对于大多数矿床，有机质在决定矿石矿物沉淀的位置和机制方面发挥主动作用还是被动作用仍不清楚。 拟议的研究旨在确定有机质对 Alligator Ridge 沉积物金矿地球化学演化的影响，Alligator Ridge 是此类类型中唯一的大型矿床，但 Alligator Ridge 是唯一一个加热没有消除原始有机质的大型矿床。记录。 使用“Rock-Eval”和脂肪族烃提取物进行的初步分析表明，有机物不是惰性的，而是被矿化溶液氧化的。 然而，许多氧化反应是可能的（对于CO2、醚、羰基或其他基团），并且初步的热力学计算表明它们在很宽的氧化还原条件下发生。 建议通过以下方式确定氧化和矿化反应的性质：（1）干酪根的提取和红外分析以识别氧化化合物； (2) 热力学计算，将有机质的氧化还原状态与矿石和蚀变矿化的氧化还原状态进行比较。 成功完成拟议的研究将有助于更深入地了解有机质对金沉积地点和机制的影响，并可能为发现新矿床提供更具成本效益的方案。