Origins of Gold, Uraninite, Pyrite, and Organic Matter in Conglomerates of Archean and Early Proterozoic Age

太古宙和早元古代砾岩中金、铀矿、黄铁矿和有机质的起源

• 批准号: 9706279
• 负责人: Hiroshi Ohmoto
• 金额: $ 18万
• 依托单位: Pennsylvania State Univ University Park
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-06-01 至 2000-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9706279&HistoricalAwards=false
• 关键词: Origins; Gold; Uraninite; Pyrite; Organic

9706279 Ohmoto The goal of this research is to develop a comprehensive model for the formation processes of gold-uranium deposits occurring in conglomerate beds of ~2.8 Ga to ~2.0 Ga and their paleoenvironments. The results of this study will lead to a better exploration model for this most important class of mineral deposits, and to a better understanding of the evolutionary history of the early EarthOs atmosphere and biosphere. The research goal will be achieved by seeking solutions to three major problems: (1) what are the origins of gold, uraninite, and pyrite: detrital, diagenetic, or hydrothermal?; (2) what are the origins of the fluids involved in dissolution/precipitation of gold, uraninite, and pyrite: oxygen-bearing ground water or high temperature hydrothermal fluid?; and (3) what are the origins of organic matter: indigenous microbial mats or extraneous petroleum? Solutions to these three problems will be sought from detailed and systematic investigations of a variety of minerals and organic matter in ore and country rocks in the Witwatersrand district, South Africa, and the Elliot Lake district, Canada. The investigations will focus on micro-scale variations in mineralogical characteristics (morphology, texture, abundance, paragenesis), chemical characteristics (major, trace, and rare earth elements), and stable isotopic characteristics (H, O, C, and S).

本研究的目的是建立一个综合的模式，金铀矿床的形成过程中的砾岩层~2.8 Ga ~2.0 Ga和他们的古环境。 这项研究的结果将为这类最重要的矿床提供更好的勘探模型，并更好地了解早期地球大气和生物圈的演变历史。 研究目标将通过解决三个主要问题来实现：（1）金、晶质铀矿和黄铁矿的成因是什么：碎屑、成岩还是热液？(2)参与金、晶质铀矿和黄铁矿溶解/沉淀的流体的来源是什么：含氧地下水还是高温热液流体？（3）有机质的起源是什么：原生微生物垫还是外来石油？ 这三个问题的解决方案，将寻求从详细和系统的调查各种矿物和有机物的矿石和围岩在威特沃特斯兰德区，南非，埃利奥特湖区，加拿大。调查将侧重于矿物学特征（形态，结构，丰度，共生），化学特征（主要，微量和稀土元素）和稳定同位素特征（H，O，C和S）的微观变化。