Evaluation of Sulfidation as the Cause of Gold Deposition in Carlin-type Deposits

卡林型矿床硫化成金成因评价

• 批准号: 9804963
• 负责人: Stephen Kesler
• 金额: $ 17.97万
• 依托单位: Regents of the University of Michigan - Ann Arbor
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-01-01 至 2002-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9804963&HistoricalAwards=false
• 关键词: Evaluation; Sulfidation; Cause; Gold; Deposition

9804963KeslerThis study is designed to shed light on processes that deposit gold in Carlin-type deposits, which are the main source of gold outside South Africa. Gold in these deposits is found in arsenic-rich pyrite that is disseminated throughout the host rocks. Previous work at one deposit, Twin Creeks, shows that: 1) iron in mineralized rocks with high concentrations of gold is in pyrite, 2) iron in barren rock that lacks gold is in minerals other than pyrite, and 3) iron contents of mineralized and barren rocks are the same. These relations suggest that iron in mineralized rocks was converted to pyrite and that this caused gold deposition by the process known as sulfidation. The present study will attempt to determine whether sulfidation took place at other Carlin-type deposits and whether this is a general mechanism for deposition of gold in these deposits. This study also will test preliminary observations at Twin Creeks which suggest that the distribution of ferroan dolomite in sedimentary rocks reflects their post-depositional history. The results of this research will be useful in guiding exploration for new Carlin-type deposits.

这项研究旨在阐明卡林型矿床中的黄金沉积过程，卡林型矿床是南非以外的主要黄金来源。这些矿床中的金是在富砷黄铁矿中发现的，这种黄铁矿分散在整个主岩中。双溪矿床的前人研究表明：1)含金量高的矿化岩石中铁在黄铁矿中；2)缺乏金的贫瘠岩石中的铁存在于黄铁矿以外的矿物中；3)矿化岩石和贫化岩石中的铁含量相同。这些关系表明，矿化岩石中的铁被转化为黄铁矿，这导致了金的沉积过程，称为硫化作用。本研究将试图确定其他卡林型矿床是否发生了硫化作用，以及这是否是这些矿床中金沉积的一般机制。这项研究还将检验双溪的初步观察结果，这些观察结果表明，沉积岩中铁质白云石的分布反映了它们的后沉积历史。这一研究成果将对新的卡林型矿床的勘探起到指导作用。