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

9804963 Kesler这项研究旨在阐明卡林型矿床中存款金的过程，卡林型矿床是南非以外的主要黄金来源。这些矿床中的金存在于富砷黄铁矿中，黄铁矿散布在整个寄主岩石中。以前在一个存款，双溪，工作表明：1）铁矿化岩石中的高浓度的金是在黄铁矿，2）铁贫瘠的岩石，缺乏金是在矿物中的黄铁矿以外，和3）矿化和贫瘠的岩石的铁含量是相同的。这些关系表明，矿化岩石中的铁被转化为黄铁矿，这导致金沉积的过程称为硫化。本研究将试图确定硫化是否发生在其他卡林型矿床，这是否是一个一般的机制，在这些矿床的金沉积。这项研究还将测试在Twin Creeks的初步观察结果，这些观察结果表明，沉积岩中含铁白云石的分布反映了沉积后的历史。研究结果对指导寻找新的卡林型矿床具有重要意义。

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.